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Evaluating the Effects of Gamma-Irradiation for Decontamination of Medicinal Cannabis

  • Hazekamp Herbal Consulting

Abstract and Figures

In several countries with a National medicinal cannabis program, pharmaceutical regulations specify that herbal cannabis products must adhere to strict safety standards regarding microbial contamination. Treatment by gamma irradiation currently seems the only method available to meet these requirements. We evaluated the effects of irradiation treatment of four different cannabis varieties covering different chemical compositions. Samples were compared before and after standard gamma-irradiation treatment by performing quantitative HPLC analysis of major cannabinoids, as well as qualitative GC analysis of full cannabinoid and terpene profiles. In addition, water content and microscopic appearance of the cannabis flowers was evaluated. This study found that treatment did not cause changes in the content of THC and CBD, generally considered as the most important therapeutically active components of medicinal cannabis. Likewise, the water content and the microscopic structure of the dried cannabis flowers were not altered by standard irradiation protocol in the cannabis varieties studied. The effect of gamma-irradiation was limited to a reduction of some terpenes present in the cannabis, but keeping the terpene profile qualitatively the same. Based on the results presented in this report, gamma irradiation of herbal cannabis remains the recommended method of decontamination, at least until other more generally accepted methods have been developed and validated.
Content may be subject to copyright.
published: 27 April 2016
doi: 10.3389/fphar.2016.00108
Frontiers in Pharmacology | 1April 2016 | Volume 7 | Article 108
Edited by:
Adolfo Andrade-Cetto,
Universidad Nacional Autónoma de
México, Mexico
Reviewed by:
Jürg Gertsch,
University of Bern, Switzerland
Ashwell Rungano Ndhlala,
Agricultural Research Council,
South Africa
Ildikó Rácz,
University of Bonn, Germany
Arno Hazekamp
Specialty section:
This article was submitted to
a section of the journal
Frontiers in Pharmacology
Received: 25 January 2016
Accepted: 11 April 2016
Published: 27 April 2016
Hazekamp A (2016) Evaluating the
Effects of Gamma-Irradiation for
Decontamination of Medicinal
Cannabis. Front. Pharmacol. 7:108.
doi: 10.3389/fphar.2016.00108
Evaluating the Effects of
Gamma-Irradiation for
Decontamination of Medicinal
Arno Hazekamp *
Head of Research and Education, Bedrocan International BV, Veendam, Netherlands
In several countries with a National medicinal cannabis program, pharmaceutical
regulations specify that herbal cannabis products must adhere to strict safety standards
regarding microbial contamination. Treatment by gamma irradiation currently seems the
only method available to meet these requirements. We evaluated the effects of irradiation
treatment of four different cannabis varieties covering different chemical compositions.
Samples were compared before and after standard gamma-irradiation treatment by
performing quantitative UPLC analysis of major cannabinoids, as well as qualitative
GC analysis of full cannabinoid and terpene profiles. In addition, water content and
microscopic appearance of the cannabis flowers was evaluated. This study found that
treatment did not cause changes in the content of THC and CBD, generally considered as
the most important therapeutically active components of medicinal cannabis. Likewise,
the water content and the microscopic structure of the dried cannabis flowers were not
altered by standard irradiation protocol in the cannabis varieties studied. The effect of
gamma-irradiation was limited to a reduction of some terpenes present in the cannabis,
but keeping the terpene profile qualitatively the same. Based on the results presented
in this report, gamma irradiation of herbal cannabis remains the recommended method
of decontamination, at least until other more generally accepted methods have been
developed and validated.
Keywords: medicinal cannabis, cannabinoids, terpenes, gamma-irradiation, quality control
Because medicinal cannabis is often used by chronically ill patients affected by a weakened immune
system, pharmaceutical regulations in countries such as The Netherlands and Canada specify that
these products must adhere to strict safety standards regarding microbial contamination. When
harmful microbes or fungal spores are inhaled during e.g., vaporizing or smoking, they may directly
enter the bloodstream and cause opportunistic infections. Such contamination risks are not merely
hypothetical: cases of chronic pulmonary aspergillosis associated with smoking unsafe cannabis are
well established in the scientific literature (Llamas et al., 1978; Sutton et al., 1986; Marks et al., 1996;
Szyper-Kravitz et al., 2001; Kouevidjin et al., 2003; Cescon et al., 2008; Bal et al., 2010; Ruchlemer
et al., 2015). For those with compromised immune systems, such lung diseases could be even fatal
(Hamadeh et al., 1988).
Hazekamp Effects of Gamma-Irradiation on Medicinal Cannabis
To minimize contamination risks to patients, Dutch
regulations demand that medicinal cannabis contains no more
than 100 colony-forming units (CFUs) per gram of final product,
which is close to sterility1. Under the Canadian program, limits
are somewhat higher with a maximum of 1.000 CFUs per gram2.
Following European or US Pharmacopoeia standards for inhaled
preparations, certain specific pathogens must be completely
absent, i.e., Staphylococcus aureus,Pseudomonas aeruginosa,
and any bile-tolerant Gram-negative bacteria such as E. coli
(EP, 2015; USP, 2015). Furthermore, the absence of fungal
mycotoxins must be confirmed by additional quality control
Decontamination of medicinal (herbal) cannabis is a
necessity, as it has yet not been possible to grow cannabis plants
under sufficiently sterile conditions to keep contamination
levels below the required safety limits. Even if this were feasible,
the multiple steps involved in harvesting, drying, processing
and packaging cannabis buds would make it extremely hard
to maintain near-sterile conditions throughout the entire
production procedure. As a result, medicinal cannabis in The
Netherlands as well as in Canada is treated by gamma irradiation
before it becomes available to patients1,2.
Methods of Decontamination
Reduction of microbes can be achieved by various treatments, as
listed in Table 1. The optimal choice of decontamination depends
on the nature of the product to be treated. For herbal materials
such as cannabis, the only currently viable option for treatment is
the use of ionizing radiation. Any of the other decontamination
treatments would either affect chemical content or texture (i.e.,
heat, chemicals, pressure, steam; Ruchlemer et al., 2015) or would
not penetrate beyond the surface of the dense cannabis flowers
(i.e., UV-light).
Gamma irradiation involves exposing the target material to
packets of light (photons) that are so highly energetic (gamma
rays) that they damage the DNA strands present in microbes. As
a result, the affected microbes cannot multiply, and consequently
they will perish3. Because medicinal cannabis is a harvested and
dried (i.e., non-living) product, this effect is not relevant for the
condition of the cannabis plant cells.
Irradiation Safety and Concerns
Most commonly, the radioactive element cobalt-60 (60Co) is
used as the source for gamma irradiation. If administered at
appropriate levels, irradiation can be used for the removal of
decay-causing bacteria from many foods and herbs, and can
prevent sprouting of fruit and vegetables to maintain freshness
and flavor (EFSA Panel on Food Contact Materials Enzymes
Flavourings Processing Aids-CEF, 2011; Arvanitoyannis et al.,
2009). Decontamination or sterilization by gamma irradiation
is also widely applied to medical instruments and medicines
(Hasanain et al., 2014).
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TABLE 1 | List of current main methods available for decontamination or
sterilization of (food) products.
Type of decontamination Main treatments
Heat: Dry heat
Steam (autoclave)
Chemicals: Gas (ethylene oxide, ozone, nitrogen dioxide)
Liquid (hydrogen peroxide, formaldehyde)
High pressure: Pascalization
Filtration: Micropore filter (NB: for liquids only)
Radiation: Non-ionizing (UV-light)
Ionizing (gamma-irradiation, X-rays, electron beam)
Over the years, the safety of irradiated foods has been
confirmed in various animal as well as human studies. These
include animal feeding studies lasting for several generations
in several different species, including mice, rats and dogs
(WHO, 1999; EFSA Panel on Food Contact Materials Enzymes
Flavourings Processing Aids-CEF, 2011). NASA astronauts have
been eating irradiated foods when they fly in space since the
1970s (Perchonok and Bourland, 2002). Irradiation-induced
changes in food components are generally small and not
significantly different from those reported in other conventional
preservation processes, especially those based on thermal
treatment (EFSA Panel on Food Contact Materials Enzymes
Flavourings Processing Aids-CEF, 2011; Shahbaz et al., 2015).
The changes in some components that are sensitive to irradiation,
like some vitamins or micronutrients (Caulfield et al., 2008) may
be minimized by using proper treatment conditions (Kilcast,
1994; WHO, 1999).
The safety of irradiated foods has been endorsed by the
World Health Organization (WHO), the Food and Agriculture
Organization of the United Nations (FAO), the U.S. Department
of Agriculture (USDA), Health Canada (HC), the European
Union (EU), and the Food and Drug Administration (FDA).
Gamma irradiation is now permitted by over 60 countries with
at least 400,000 metric tons of foodstuffs annually processed
worldwide (EFSA Panel on Food Contact Materials Enzymes
Flavourings Processing Aids-CEF, 2011). The regulations that
dictate how food is to be irradiated, as well as which foods
are allowed to be treated, may vary greatly from country to
Despite these developments, irradiation remains a somewhat
controversial decontamination technique that can spark
emotional debates among the general public. One specific
concern with irradiation treatment is the formation of radiolytic
compounds, in particular 2-alkylcyclobutanones (2-ACBs).
These chemicals are formed in minute quantities when high
fat containing foods (such as sesame seeds, pork meat, cheese,
eggs, fish) are subjected to gamma irradiation, and their content
increases with irradiation dose (Zanardi et al., 2007; Lee et al.,
2008). Although some contradictory in vitro findings exist on
the safety of these compounds, overall scientific consensus is that
2-ACBs are not an immediate cause for concern (EFSA Panel
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Hazekamp Effects of Gamma-Irradiation on Medicinal Cannabis
on Food Contact Materials Enzymes Flavourings Processing
Aids-CEF, 2011).
Of course, consumers may also be concerned about the
indirect effects of irradiation, such as the way it changes
the way we relate to food or herbal medicine, or how the
use of radioactive materials affect the environment during
their mining, shipping and use. Furthermore, irradiation,
like any form of treatment, adds to the final cost of a
food product or medicine. All these concerns should be
taken into consideration when determining whether gamma
irradiation is the proper choice for decontamination of a
Evaluating the Effects of Gamma
Irradiation on Medicinal Cannabis
Patients have occasionally expressed their concerns about the
effects of irradiation treatment on medicinal cannabis. Some
have claimed a change of taste or effect, while others worry
about changes in the chemical composition or the quality of
their medicine5. In response to such concerns, some Canadian
licensed producers of medicinal cannabis initially pledged not
to apply irradiation, but were forced to reconsider when their
products could not meet microbial safety requirements. To
cushion the impact on their customers, the obscuring term “cold
pasteurization” was introduced when in fact gamma irradiation
treatment was applied6.
In fresh Cilantro leaves, gamma irradiation was shown to
reduce the content of terpenes such as myrcene and linalool (Fan
and Sokorai, 2002). Likewise, irradiation may perhaps have an
effect on cannabis terpenes, which seem to play an important
role in the synergistic effect and bioavailability of cannabinoids
(Russo, 2011). Although an early study by our group on
the effect of cannabis irradiation did not indicate changes in
the cannabinoid profile (unpublished data), chromatographic
analysis of cannabinoids has significantly improved over the
years meaning that more detailed changes in the cannabinoid
profile may now be visualized. The occurrence of 2-ACBs
seems of limited relevance in the case of cannabis, because
average daily cannabis consumption is very small compared to
other irradiated products such as meats, fruits of vegetables.
Also, cannabis flowers do not contain significant amounts
of fat needed to form these radiolytic compounds in the
first place.
To address the concerns that may exist around gamma
irradiation of medicinal cannabis, we evaluated the effects of
irradiation treatment of four different cannabis varieties covering
different compositions (THC vs. CBD dominant types, Sativa
vs. Indica types). Samples were compared before and right
after standard gamma-irradiation treatment, by performing
quantitative analysis of major cannabinoids, as well as qualitative
analysis of full cannabinoid and terpene profiles. In addition,
water content and microscopic appearance of the cannabis
flowers was evaluated.
5 an/securit/irridation/cyclobutanone-eng.php
6 marijuana-orders-
Solvents and Chemicals
All organic solvents were HPLC or analytical grade. Acetonitrile
was obtained from Boom labs BV (Meppel, The Netherlands).
Ethanol and phosphorus pentoxide (P4O10) was purchased from
VWR (Amsterdam, The Netherlands).
Cannabis Samples
Pharmaceutical-grade cannabis was obtained from the licensed
Dutch cultivator, Bedrocan BV (Veendam, the Netherlands).
Plants were grown from genetically identical clones under
standardized indoor conditions. Flower tops were harvested
and air-dried for 1 week under controlled temperature and
humidity. Four different standardized varieties available in
Dutch pharmacies were used for this study i.e., Bedrocan R
Bediol R
,Bedica R
, and Bedrolite R
. Batch information
and chemical composition of these products is listed in
Table 2.
All cannabis batches used for this study were harvested in the
period of late 2014–early 2015. Following standard procedure,
each batch was packaged in portions of 250 grams in triple
laminate foil bags with zip-lock closure (type Lamizip aluminum;
Daklapack, The Netherlands) for gamma irradiation treatment
at Synergy Health (Etten-Leur, The Netherlands). Each batch
received an irradiation dose of (minimum) 10 kGy produced with
a Cobalt-60 radiation source.
Of each cannabis variety a 10 gram sample was collected
before (non-irradiated control) as well as after (irradiated
sample) gamma irradiation, resulting in a total of 8 samples for
this study [4 varieties ×2 treatments (before/after irradiation)].
Samples were homogenized by grinding in a blender until the
material was about 5 mm in diameter. Ground samples were
finally used for determination of water content, and for sample
extraction for GC/UPLC analysis. Of variety Bedrocan, the
most popular variety used by Dutch patients (Hazekamp and
Heerdink, 2013), some non-homogenized samples were kept for
microscopic analysis.
All samples were handled and stored under equivalent
conditions. For each variety, irradiated and control samples
were extracted and analyzed on the same day, so that any
changes in chemical composition could only be attributed
to the irradiation treatment. This study was carried out
under a cannabis research license issued by the Dutch Health
TABLE 2 | Cannabis type and batch information of the cannabis varieties
used in this study.
Variety name Batch # THC/CBD
Harvest date
Bedrocan A1.01.45 THC Sativa 11-12-2014
Bediol A2.05.15 THC +
Sativa 25-12-2014
Bedrolite A2.08.13 CBD Sativa 08-01-2015
Bedica A2.07.20 THC Indica 22-01-2015
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Hazekamp Effects of Gamma-Irradiation on Medicinal Cannabis
FIGURE 1 | Structures of the cannabinoids quantitatively analyzed by UPLC.
Water Content Determination
Water content of each homogenized sample was determined
by using the Loss on Drying (LOD) method according
to EP monograph 2.3.32 (method C). In short, 500 mg of
each sample (in duplicate) was accurately weighed in small
plastic containers, and dried for 24 h at 40C under vacuum
inside a desiccator containing the potent desiccant phosphorus
pentoxide. Subsequently, all samples were weighed again. Water
content (in percentage of initial weight) was determined by
comparing weight before and after the procedure.
Sample Extraction
Ground cannabis samples were extracted for Gas
Chromatography (GC) and Ultra-Performance Liquid
Chromatography (UPLC) analysis as described in the
Dutch Analvtical Monograph for release testing of Cannabis
Flos, version 7.1 (OMC, 2015)7. In short, 1000 mg of each
specificaties-en- analysevoorschriften
homogenized sample (in duplicate) was extracted with 40 mL
of absolute ethanol in plastic serum tubes (maximum content
50 mL) while mechanically shaking for 15 min at 300 rpm.
Tubes were then centrifuged at 3000 rpm and clear supernatant
was transferred to a 100 mL volumetric flask. For exhaustive
extraction, the procedure was repeated twice more with 25 mL
of ethanol, and supernatants were combined. Volumes were
adjusted to 100 mL with ethanol, mixed well, and filtered through
a 0.45 µm PTFE syringe filter to remove small particles. Filtrated
extracts were used directly for GC analysis, or further diluted
with acetonitrile/water (70:30, v/v) for analysis by UPLC.
Quantitative UPLC Analysis of Major
The UPLC profiles were acquired on a Waters (Milford, MA)
Acquity UPLC system consisting of a gradient pump, an
autosampler, a column oven and a diode array detector (DAD).
The device was controlled by Waters Empower software. Full
spectra were recorded in the range of 200–400 nm. The analytical
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Hazekamp Effects of Gamma-Irradiation on Medicinal Cannabis
FIGURE 2 | Total THC and total CBD content (in % of dry weight) as determined by UPLC analysis, as well as water content (in % of total weight) as
determined by Loss on Drying method (LOD) in all studied varieties before (gray bars) and after (black bars) irradiation treatment.
column was a Waters Aquity C18 (1.7 µm, 2.1 ×150 mm)
equipped with a matching guard column. The mobile phase
consisted of a gradient of acetonitrile (A) and water (B), both
containing 0.1% formic acid. The gradient was programmed as
follows: 0–6 min (hold at 70% A); 6–10.5 min (linear increase to
100% A); 10.5–11 min (hold at 100% A). The column was then
re-equilibrated under initial conditions for 1.5 min, resulting in a
total runtime was 12.5 min. Flow-rate was 0.4 mL/min. Injection
volume was 10 µL. Chromatographic peaks were recorded at
228 nm. All determinations were carried out at 30C. All samples
were analyzed in duplicate.
Applying the standard protocol for release testing of medicinal
cannabis (OMC, 2015)7, the following cannabinoids were
quantitatively determined: THC, THCA, CBD, CBDA, delta-8-
THC, CBN. The structures of these compounds, including their
full chemical names, are shown in Figure 1.
Qualitative GC Analysis of Cannabinoid
and Terpene Profiles
Gas chromatography was used for the simultaneous qualitative
analysis of monoterpenes, sesquiterpenes, and cannabinoids
as previously reported (Hazekamp and Fischedick, 2012). An
Agilent GC 6890 series (Agilent Technologies Inc., Santa Clara,
CA, USA) equipped with a 7683 autosampler and a flame
ionization detector (FID) was used. The instrument was equipped
with a DB5 capillary column (30 m length, 0.25 mm internal
diameter, film thickness 0.25 µm; J&W Scientific Inc., Folsom,
CA, USA). The injector temperature was 230C, with an injection
volume of 1 µl, a split ratio of 1:20 and a carrier gas (N2) flow
rate of 1.2 ml/min. The temperature gradient started at 60C and
linearly increased at a rate of 3C/min until the final temperature
of 240C which was held for 5 min resulting in a total run time of
65 min/sample. The FID detector temperature was set to 250C.
The device was controlled by Agilent GC Chemstation software
version B.04.01.
Microscopic Visualization of Glandular
In order to visualize potential morphological changes in
the glandular hairs (where cannabinoids and terpenes are
produced) present in the cannabis flowers, microscopic
analysis of cannabis variety Bedrocan was performed before
and after gamma-irradiation treatment. Whole cannabis
flowers were used, without homogenizing. A Leica (type
MZ16FA) stereo-microscope was used. Images were captured
at a magnification factor ranging from 20 to 120 times
with a Leica (type DFC420C) camera, controlled by LAS
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Hazekamp Effects of Gamma-Irradiation on Medicinal Cannabis
FIGURE 3 | Continued
Loss on Drying
Inhalation, either by smoking or vaporizing, is currently the main
mode of administration used by patients (Hazekamp et al., 2013).
Water content (humidity) seems to have significant impact on
how consumers appreciate medicinal cannabis products during
inhalation (Ware et al., 2006). Although gamma irradiation does
not significantly heat up the treated product, water may be lost
during the procedure either as a result of the irradiation itself
(Yu and Wang, 2007) or because of shipping and handling
of the product during the treatment. Release specifications for
Bedrocan products require the water content to be no more
than 10%. As shown in Figure 2, the actual water content of the
analyzed varieties ranged between 5 and 8%, with no differences
between treated and control samples.
UPLC Analysis
Six major cannabinoids were quantitatively analyzed by applying
a validated UPLC methodology that is used as standard
procedure for release testing of medicinal cannabis in The
Netherlands. As customary, the sum of THC and its acidic
precursor THCA is reported as “total THC content.” Similarly,
the sum of CBD and CBDA is reported as “total CBD content.”
It should be noted that delta-8-THC and CBN are not originally
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Hazekamp Effects of Gamma-Irradiation on Medicinal Cannabis
FIGURE 3 | Continued
produced by the cannabis plant, but are formed as degradation
products of THC by exposure to heat or light, or by prolonged
storage (Hazekamp et al., 2010).
Results of cannabinoid testing are shown in Figure 2,
indicating that levels of total THC and/or CBD were not altered
by irradiation treatment in any of the varieties studied. No delta-
8-THC or CBN was detected in any of the samples (before or
after irradiation) at levels over 0.1% (which equals 1 mg/gram of
cannabis flower).
GC Analysis
Components visualized by GC analysis were not individually
quantified because of the multitude of chromatographic peaks
of interest (>50). Instead, the entire profiles of all visible
peaks are presented in Figure 3. Because of the complexity of
these profiles, the sections of the profile where monoterpenes,
sesquiterpenes, and cannabinoids elute are displayed separately.
For each variety, control (non-irradiated) samples, and treated
(irradiated) samples are shown side by side, using the same
vertical scale to allow direct comparison. The main peaks in
each variety were identified based on previously published data
(Hazekamp and Fischedick, 2012).
While the overall qualitative composition of the samples
was unaltered, differences in several terpene components could
be detected after irradiation in the cannabis varieties studied.
Components that showed a clear reduction after irradiation
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Hazekamp Effects of Gamma-Irradiation on Medicinal Cannabis
FIGURE 3 | Continued
treatment are indicated in Figure 3 by showing the relative
change (in %) compared to untreated sample. Because a small
variability of terpene content between samples is to be expected,
and is also observed between replicates of non-treated samples,
changes that are smaller than +/– 5% are not indicated. The
main components affected were the monoterpenes myrcene,
cis-ocimene and terpinolene, and the sesquiterpenes gamma-
selinene, eudesma-3,7(11)-diene and gamma-selinene. No new
terpene peaks were formed as a result of treatment. No
cannabinoids were altered or formed as a result of irradiation.
Multiple microscopic images were obtained of variety
Bedrocan on flowers collected before and after treatment
with gamma-irradiation, at a magnification of about 20–120
times. The trichomes (glandular hairs) where cannabinoid and
terpenes are excreted by the cannabis plant are clearly visible, as
shown in Figure 4. No clear differences in trichome structure,
color, density, or shape could be observed between the control
(non-irradiated) samples and treated (irradiated) samples.
Gamma irradiation treatment of cannabis has become standard
practice in the government-supported medicinal cannabis
programs of The Netherlands as well as Canada. In the study
presented here such treatment, at a radiation dose (10 kGy)
sufficient to reduce microbial contamination (bioburden) to
pharmaceutically acceptable levels, did not cause any changes
in the content of THC and CBD, generally considered as the
most important therapeutically active components of medicinal
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Hazekamp Effects of Gamma-Irradiation on Medicinal Cannabis
FIGURE 3 | GC profiles of four studied varieties showing monoterpenes, sesquiterpenes, and cannabinoids in separate sections. C, control
(non-irradiated); T, treated (irradiated); *: artifact. Numbers indicate percentage of change in treated samples compared to non-treated controls.
cannabis (Grotenhermen and Müller-Vahl, 2012). Likewise, the
water content and the microscopic structure of the dried cannabis
flowers were not altered by standard irradiation protocol in four
different cannabis varieties. The study included representative
varieties of THC and CBD dominant types, as well as Sativa and
Indica types.
In our study, irradiation had a measurable effect on the
content of multiple cannabis terpenes, mainly on the more
volatile monoterpenes. Reduction of affected terpenes was in
general between 10 and 20%, but for some components this
may be as much as 38%. In a previous study evaluating
the effect of gamma irradiation on fresh Cilantro, a decrease
in terpene content was also described (Fan and Sokorai,
2002). However, the authors concluded that the observed loss
of terpenes such as myrcene and linalool was insignificant
compared to the losses that occurred by evaporation during
refrigerated storage of Cilantro. Also in orange juice the effect
of irradiation on terpenes was found to be non-significant
in comparison to changes induced by refrigerated storage
(Fan and Gates, 2001). Likewise, the slight terpene reduction
observed in the current study is comparable to the effect
that short term storage in a paper bag had on cannabis
samples, in a study performed by (Ross and ElSohly, 1996).
A likely explanation therefore seems that gamma irradiation
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Hazekamp Effects of Gamma-Irradiation on Medicinal Cannabis
FIGURE 4 | Microscopic images of trichomes (glandular hairs) before and after treatment with gamma-irradiation. Cannabis variety Bedrocan was used.
Magnification ±20–120 times.
slightly accelerates the evaporation of some of the more volatile
terpenes. This idea is supported by the fact that no degradation
products or additional chromatographic peaks were found to
account for the lost terpenes, with the exception of some
beta-caryophyllene oxide formed in the irradiated sample of
variety Bedica. Interestingly, terpenes were not affected to the
Frontiers in Pharmacology | 10 April 2016 | Volume 7 | Article 108
Hazekamp Effects of Gamma-Irradiation on Medicinal Cannabis
same degree in all varieties, e.g., myrcene content was clearly
reduced in varieties Bedica and Bedrolite but not in variety
Bediol. Perhaps this indicates a protective effect that cannabis
components may have on each other when present in specific
Some cannabis users have claimed that irradiation changes
the taste and/or smell of cannabis during smoking or vaporizing
(personal observation by the author). Unfortunately, such
opinions may be hard to substantiate because the same cannabis
is usually not available to consumers in both its irradiated and
non-irradiated form to allow direct comparison, meaning there is
no “base-line” product to quantify the magnitude of the change.
Nevertheless, the taste and smell of cannabis mainly depends
on its terpene (essential oil) content (Russo, 2011). While the
current study indicated quantitative changes in some of the
terpenes upon irradiation, a subtle change in smell or taste may
indeed be possible as a result of such treatment. Despite these
changes, the overall terpene profile of each variety remained
clearly recognizable.
Gamma irradiation remains controversial among some
consumers of medicinal cannabis. However, weighing the risks
vs. the benefits currently keeps pointing toward the use of this
decontamination procedure. After all, cannabis plants cannot
(yet) be grown and processed under conditions aseptic enough
to meet pharmaceutical standards, while infection risks are well
documented in the medical literature and can be harmful or
even fatal to seriously ill patients. Meanwhile, the main harm of
gamma-irradiation seems to be limited to a reduction of some
terpenes present in the cannabis, leading to a small quantitative
effect, but keeping the terpene profile qualitatively essentially
Based on the results presented in this report, gamma
irradiation of herbal cannabis remains the recommended method
of decontamination, at least until other more generally accepted
methods have been developed and validated. This is especially
important when cannabis is prescribed to seriously ill and
possibly immune-deprived patients, with an increased risk of
suffering from microbial infection. Meanwhile, the development
of improved hygienic standards for cultivation and processing
of medicinal cannabis may ensure that irradiation doses can be
reduced to an absolute minimum. In time, gamma-irradiation
may eventually be replaced with other, more generally accepted,
forms of reliable decontamination.
The author confirms being the sole contributor of this work and
approved it for publication.
The Dutch Office of Medicinal Cannabis (OMC) and
pharmaceutical quality control laboratory Proxy Labs (Leiden,
The Netherlands) are gratefully acknowledged for their support
in performing this study. A big thanks to Gerda Lamers (Leiden
University) for preparing the microscopic images.
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Conflict of Interest Statement: The author is full time employed by Bedrocan BV,
the licensed company that provided the medicinal grade cannabis used for this
Copyright © 2016 Hazekamp. This is an open-access article distributed under the
terms of the Creative Commons Attribution License(CC BY). The use, distribution or
reproduction in other forums is permitted, provided the original author(s) or licensor
are credited and that the original publication in this journal is cited, in accordance
with accepted academic practice. No use, distribution or reproduction is permitted
which does not comply with these terms.
Frontiers in Pharmacology | 12 April 2016 | Volume 7 | Article 108
... Gamma radiation, a common method for food product sterilization, is the preferred decontamination process. 26,27,30,31 This process uses ionizing radiation exposure to kill pathogens and maintain a low microbial contamination level. 7 Available evidence supports that irradiated cannabis is safe and does not alter THC or CBD content. ...
... 7 Available evidence supports that irradiated cannabis is safe and does not alter THC or CBD content. 30,31 Some reductions in terpenes have been reported. 30 However, the significance of this reduction remains to be determined and gamma radiation is still considered the best method of decontamination. ...
... 30,31 Some reductions in terpenes have been reported. 30 However, the significance of this reduction remains to be determined and gamma radiation is still considered the best method of decontamination. 7,27 FIG. 2. Common cannabis warning labels. ...
Increase in medical cannabis use, along with available products, warrants the need for clinicians to be knowledgeable in evaluating the quality of any cannabis product presented in clinical practice. Determining whether a product is regulated within the region is key in assessing overall quality and safety. Regulated products are held to a higher standard including independent testing, contamination mitigation, and concentration limits. Here, we present a clinical framework in evaluating cannabis products to ascertain the quality and regulation level of the product. Evaluation includes assessing the source company, reviewing product details (e.g., type, cannabinoid content, and labeling), and assessing quality control variables such as manufacturing and decontamination processes. The quality of products patients use is an important part of mitigating cannabis-related harms, especially in medically vulnerable patients. Currently, there is a great need to implement widespread standardization and regulations to ensure product quality and safety.
... Hazekamp investigated the effects of gamma irradiation on the overall quality of cannabis and found that this technique does have drawbacks, especially in the context of terpene content, which is of utmost importance for the therapeutic properties of cannabis. Figure 6.5 from his work demonstrates up to a 38% reduction in the monoterpene terpinolene and conversion of the sesquiterpene β-caryophyllene into its oxidized counterpart caryophyllene oxide increasing its concentration by 75% (Hazekamp 2016). However, in the case of terpinolene it is important to note that a similar level of reduction would be seen if stored in a plastic bag. ...
... C, control (nonirradiated); T, treated (irradiated); *, artifact. Numbers indicate the percentage of change in treated samples compared to non-treated controls(Hazekamp 2016). ...
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The microbial testing of cannabis and cannabis products presents a unique set of challenges. Unlike food testing, cannabis testing has various routes of administration to take into account. Cannabis flowers express high levels of antimicrobial cannabinoids and terpenoids and thus represent a different matrix than traditional foods. It is currently estimated that 50% of cannabis is consumed via vaporizing or smoking oils and flowers while the other half is consumed as Marijuana Infused Products or MIPs which encompass a wide variety of matrices. In a testing landscape that consistently focuses heavily on chemical analysis, the microbiological testing of cannabis is often overlooked. However, it is truly one of the most important analyses in the context of product safety as the accidental ingestion or inhalation of these contaminants can cause severe illnesses, infections, or worse, death. The present chapter explores the microbial contaminants of interest in cannabis, current testing methodologies, and the challenges that testing laboratories face in this continuously evolving domain. Different perspectives for ensuring product safety are presented in the context of current regulations and their varying approaches. Tactics for the remediation of contaminated product and preventative strategies used by cultivators are also discussed in the context of the existing incongruent patchwork of regulatory framework. Microbial testing acceptance criteria, methods, and recommendations from various standards organizations are presented and efforts towards the standardization and development of reference methods are highlighted.
... Studies on the safety of gamma irradiation in herbal medicinal are still limited. However, the World Health Organization (WHO), the Food and Agriculture Organization of the United Nations (FAO), the U.S. Department of Agriculture (USDA), Health Canada (HC), the European Union (EU), and the Food and Drug Administration (FDA) has approved the safety of irradiated foods (Hazekamp, 2016). ...
... The main terpenes affected were the monoterpenes myrcene, cis-ocimene and terpinolene, and the sesquiterpenes gamma-selinene and eudesma-3,7(11)-diene. The terpenes were reduced but that no new compounds were formed in the cannabis due to irradiation, suggesting that the terpenes are evaporated during the process (Hazekamp, 2016). ...
The trend of consuming herbal medicines has been increasing over the past three decades. No less than 80% of the world's population has used herbal medicines as a treatment. One of the problems in herbal medicine is the high level of microbial contamination caused by raw materials and production processes. Various attempts have been made to overcome these problems, one of them is the gamma irradiation method. Although irradiation has been widely used for food sterilization, the use of irradiation for sterilization on herbal medicines is still debated. It is because irradiation may affect the composition of active compounds of herbal medicines. This review aimed to discuss the applications of gamma irradiation for herbal medicines by emphasizing the chemical constituent stabilities of herbal medicines.
... Only six European countries (Czech Republic, Denmark, Italy, Netherlands, Portugal, and Germany) have established programs allowing patients to access cannabis (i.e., herbal preparations) (42). Italy and Netherlands only permit access to cannabis decontaminated through gammairradiation [and therefore undergoing a few changes in the terpene profile (43)] (4). Pharmaceutical products containing cannabinoids are usually reimbursed from the health system under specific conditions (44). ...
... At the same time, other reports demonstrated that numerous users of recreational cannabis take it for medical reasons [61]. That is disturbing as recreational cannabis of unknown sources is likely to be contaminated with herbicides, pesticides, heavy metals, and other substances absorbed to the lungs when inhaled [63,64]. In contrast, pharmaceutical-grade cannabis is routinely tested to exclude its presence. ...
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Introduction: Medical cannabis' importance in Poland increased dramatically following its legalization as the 12th country in Europe in 2017. However, no studies have been published to give insight into Polish physicians' opinions about medical cannabis. Objectives: To investigate physician's opinions about cannabinoids' utility in clinical practice, concerns regarding their safety profile, and their clinical experience with cannabinoids. Methods: The survey using a self-developed tool was conducted online; participants were physicians with or without specialist training. Participation was voluntary. Physicians were recruited through personal networks, palliative care courses, and Medical Chambers. Results: From June to October 2020, we recruited 173 physicians from 15/16 voivodeships. The largest age group (43.9%; n = 76) was 30-39 year-olds. A similar proportion declared they never used cannabis and did not receive any training regarding cannabinoids (60% for both). Only 15 (8%) ever prescribed medical cannabis, although about 50% declared knowing suitable patients for such therapy, and 53.8% had at least one patient proactively asking for such treatment in the last 6 mo. The most common indication chosen was pain: chronic cancer-related (n = 128), chronic non-cancer (n = 77), and neuropathic (n = 60). Other commonly chosen conditions were alleviation of cancer treatment side-effects (n = 56) and cachexia (n = 57). The overall safety profile of THC was assessed as similar to most commonly used medications, including opioids; NSAIDs and benzodiazepines were, however, perceived as safer. Conclusions: Polish physicians favored the legalization of medical cannabis. However, it is of concern that a limited number have any experience with prescribing cannabis. The creation of clear guidelines to advise physicians in their routine practice and education about pain management and the risks related to the consumption of recreational cannabis for medical conditions are needed.
... Moreover, medicinal plants subjected to 50-Gy gamma irradiation had the maximal beneficial effects on stress acclimation, improvements in germination and growth/ yield parameters, and active ingredients enhancement [6,22,89]. In addition, gamma irradiation was used for decontamination in medicinal plants [28,35]. In the same context, application of low doses of gamma radiation Gy) on chilled-primed Apium graveolence (L.) seeds, either at room temperature or at 5°C, were effective in alleviating chilling stress by stimulating celery growth and proliferation [26]. ...
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Background Priming of seed prior chilling is regarded as one of the methods to promote seeds germination, whole plant growth, and yield components. The application of biostimulants was reported as beneficial for protecting many plants from biotic or abiotic stresses. Their value was as important to be involved in improving the growth parameters of plants. Also, they were practiced in the regulation of various metabolic pathways to enhance acclimation and tolerance in coriander against chilling stress. To our knowledge, little is deciphered about the molecular mechanisms underpinning the ameliorative impact of biostimulants in the context of understanding the link and overlap between improved morphological characters, induced metabolic processes, and upregulated gene expression. In this study, the ameliorative effect(s) of potassium silicate, HA, and gamma radiation on acclimation of coriander to tolerate chilling stress was evaluated by integrating the data of growth, yield, physiological and molecular aspects. Results Plant growth, yield components, and metabolic activities were generally diminished in chilling-stressed coriander plants. On the other hand, levels of ABA and soluble sugars were increased. Alleviation treatment by humic acid, followed by silicate and gamma irradiation, has notably promoted plant growth parameters and yield components in chilling-stressed coriander plants. This improvement was concomitant with a significant increase in phytohormones, photosynthetic pigments, carbohydrate contents, antioxidants defense system, and induction of large subunit of RuBisCO enzyme production. The assembly of Toc complex subunits was maintained, and even their expression was stimulated (especially Toc75 and Toc 34) upon alleviation of the chilling stress by applied biostimulators. Collectively, humic acid was the best the element to alleviate the adverse effects of chilling stress on growth and productivity of coriander. Conclusions It could be suggested that the inducing effect of the pretreatments on hormonal balance triggered an increase in IAA + GA 3 /ABA hormonal ratio. This ratio could be linked and engaged with the protection of cellular metabolic activities from chilling injury against the whole plant life cycle. Therefore, it was speculated that seed priming in humic acid is a powerful technique that can benefit the chilled along with non-chilled plants and sustain the economic importance of coriander plant productivity.
The radiation response, quantified by the dose-log survival curve, of spores of Bacillus pumilus subjected to irradiation in a 150 kV x-ray beam was examined and compared with the response obtained by irradiation in a reference cobalt-60 beam. The spores were irradiated at doses ranging from 2 kGy to 11 kGy. The response was the same for both beam qualities within measurement uncertainties. Combining these findings with our previously published data, the radiation resistance of B. pumilus spores is determined to be independent of beam quality for low and high energy x-rays, low and high energy electron beams, and cobalt-60 gamma beams.
Regulatory authorities require pharmaceuticals to be sterilized wherever practicable by a terminal sterilization method that is sterilized in the final container rather than by aseptic techniques. Hence many pharmaceuticals that are heat labile are being sterilized by gamma irradiation. In view of the increasing interest in this sterilization technology in the pharmaceutical industry, an updated review of the effects of ionizing radiation (gamma, electron beam and X-ray) on pharmaceuticals is in place. This review on the effects of irradiating pharmaceuticals and pharmaceutical materials, attempts to cover the pertinent literature from 1995 to 2020. The reviewed data give useful insights into overall radiation stability of these products, and indicate whether more extensive testing of the product is worth undertaking.
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Medical cannabis (MC) production is a rapidly expanding industry. Over the past ten years, many additional phytocannabinoids have been discovered and used for different purposes. MC was reported beneficial for the treatment of a variety of clinical conditions such as analgesia, multiple sclerosis, spinal cord injuries, Tourette's syndrome, epilepsy, glaucoma, Parkinson disease and more. Yet, there is still a major lack of research and knowledge related to MC plant diseases, both at the pre- and postharvest stages. Many of the fungi that infect MC, such as Aspergillus and Penicillium spp., are capable of producing mycotoxins that are carcinogenic, or otherwise harmful when consumed, and especially by those patients who suffer from a weakened immune system, causing invasive contamination in humans. Therefore, there are strict limits regarding the permitted levels of fungal colony forming units (CFU) in commercial MC inflorescences. Furthermore, the strict regulation on pesticide appliance application in MC cultivation exacerbates the problem. In order to meet the permitted CFU limit levels, there is a need for pesticide-free postharvest treatments relying on natural non-chemical methods. Thus, a decontamination approach is required that will not damage or significantly alter the chemical composition of the plant product. In this research, a new method for sterilization of MC inflorescences for reduction of fungal contaminantstes was assessed, without affecting the composition of plant secondary metabolites. Inflorescences were exposed to short pulses of steam (10, 15 and 20 s exposure) and CFU levels and plant chemical compositions, pre- and post-treatment, were evaluated. Steam treatments were very effective in reducing fungal colonization to below detection limits. The effect of these treatments on terpene profiles was minor, resulting mainly in the detection of certain terpenes that were not present in the untreated control. Steaming decreased cannabinoid concentrations as the treatment prolonged, although insignificantly. These results indicate that the steam sterilization method at the tested exposure periods was very effective in reducing CFU levels while preserving the initial molecular biochemical composition of the treated inflorescences.
It is imperative both healthcare providers and patients are educated on all aspects of cannabis treatment, including product safety and quality control. There are a number of quality control variables to consider when choosing medical cannabis products including contaminants, microorganisms, and pesticides. Quality control standards reduce or eliminate exposure to harmful chemicals and contaminants such as pesticides, extraction solvents, microorganisms, diluents, and fillers. These may be in a wide range of potential products which patients are considering or already using, including dried flower, oils, and concentrated products such as vapes. These are important considerations when selecting cannabis products and should not be overlooked by healthcare providers, patients, and cannabis consumers in general. Healthcare providers should be aware of which products patients are using and carefully inspect labelling. Quality control is most stringent for products that are obtained from a legal, licensed, and regulated source.
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Development of knowledge-based food preservation techniques have been a major focus of researchers in providing safe and nutritious food. Food irradiation is one of the most thoroughly investigated food preservation techniques, which has been shown to be effective and safe through extensive research. This process involves exposing food to ionizing radiations in order to destroy microorganisms or insects that might be present on and/or in the food. In addition, the effects of irradiation on the enzymatic activity and improvement of functional properties in food have also been well established. In the present review, the potential of food irradiation technology to address major problems, such as short shelf-life, high initial microbial loads, insect pest management (quarantine treatment) in supply chain, and safe consumption of fresh fruits was described. With improved hygienic quality, other uses, such as delayed ripening and enhanced physical appearance by irradiation were also discussed. Available data showed that the irradiation of fruits at the optimum dose can be a safe and cost-effective method, resulting in enhanced shelf-life and hygienic quality with the least amount of compromise on the various nutritional attributes, whereas the consumer acceptance of irradiated fruits is a matter of providing the proper scientific information.
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Medicinal cannabis is an invaluable adjunct therapy for pain relief, nausea, anorexia, and mood modification in cancer patients and is available as cookies or cakes, as sublingual drops, as a vaporized mist, or for smoking. However, as with every herb, various microorganisms are carried on its leaves and flowers which when inhaled could expose the user, in particular immunocompromised patients, to the risk of opportunistic lung infections, primarily from inhaled molds. The objective of this study was to identify the safest way of using medicinal cannabis in immunosuppressed patients by finding the optimal method of sterilization with minimal loss of activity of cannabis. We describe the results of culturing the cannabis herb, three methods of sterilization, and the measured loss of a main cannabinoid compound activity. Systematic sterilization of medicinal cannabis can eliminate the risk of fatal opportunistic infections associated with cannabis among patients at risk.
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Cannabinoids, including tetrahydrocannabinol and cannabidiol, are the most important active constituents of the cannabis plant. Over recent years, cannabinoid-based medicines (CBMs) have become increasingly available to patients in many countries, both as pharmaceutical products and as herbal cannabis (marijuana). While there seems to be a demand for multiple cannabinoid-based therapeutic products, specifically for symptomatic amelioration in chronic diseases, therapeutic effects of different CBMs have only been directly compared in a few clinical studies. The survey presented here was performed by the International Association for Cannabinoid Medicines (IACM), and is meant to contribute to the understanding of cannabinoid-based medicine by asking patients who used cannabis or cannabinoids detailed questions about their experiences with different methods of intake. The survey was completed by 953 participants from 31 countries, making this the largest international survey on a wide variety of users of cannabinoid-based medicine performed so far. In general, herbal non-pharmaceutical CBMs received higher appreciation scores by participants than pharmaceutical products containing cannabinoids. However, the number of patients who reported experience with pharmaceutical products was low, limiting conclusions on preferences. Nevertheless, the reported data may be useful for further development of safe and effective medications based on cannabis and single cannabinoids.
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Background: A growing number of countries are providing pharmaceutical grade cannabis to chronically ill patients. However, little published data is known about the extent of medicinal cannabis use and the characteristics of patients using cannabis on doctor's prescription. This study describes a retrospective database study of The Netherlands. Methods: Complete dispensing histories were obtained of all patients with at least one medicinal cannabis prescription gathered at pharmacies in The Netherlands in the period 2003-2010. Data revealed prevalence and incidence of use of prescription cannabis as well as characteristics of patients using different cannabis varieties. Results: Five thousand five hundred forty patients were identified. After an initial incidence of about 6/100,000 inhabitants/year in 2003 and 2004, the incidence remained stable at 3/100,000/year in 2005-2010. The prevalence rate ranged from 5 to 8 per 100,000 inhabitants. Virtually all patients used some form of prescription medication in the 6 months preceding start of cannabis use, most particularly psycholeptics (45.5 %), analgesics (44.3 %), anti-ulcer agents (35.9 %) and NSAIDs (30.7 %). We found no significant association between use of medication of common indications for cannabis (pain, HIV/AIDS, cancer, nausea, glaucoma) and variety of cannabis used. Conclusions: This is the first nationwide study into the extent of prescription of medicinal cannabis. Although the cannabis varieties studied are believed to possess different therapeutic effects based on their different content of tetrahydrocannabinol (THC) and cannabidiol (CBD), no differences in choice of variety was found associated with indication.
A 34-year-old man presented with pulmonary aspergillosis on the 75th day after marrow transplant for chronic myelogenous leukemia. The patient had smoked marijuana heavily for several weeks prior to admission. Cultures of the marijuana revealed Aspergillus fumigatus with morphology and growth characteristics identical to the organism grown from open lung biopsy specimen. Despite aggressive antifungal therapy, the patient died with disseminated disease. Physicians should be aware of this potentially lethal complication of marijuana use in compromised hosts.
Unlabelled: Sterilization by gamma irradiation has shown a strong applicability for a wide range of pharmaceutical products. Due to the requirement for terminal sterilization where possible in the pharmaceutical industry, gamma sterilization has proven itself to be an effective method as indicated by its acceptance in the European Pharmacopeia and the United States Pharmacopeia ( ). Some of the advantages of gamma over competitive procedures include high penetration power, isothermal character (small temperature rise), and no residues. It also provides a better assurance of product sterility than aseptic processing, as well as lower validation demands. Gamma irradiation is capable of killing microorganisms by breaking their chemical bonds, producing free radicals that attack the nucleic acid of the microorganism. Sterility by gamma irradiation is achieved mainly by the alteration of nucleic acid and preventing the cellular division. This review focuses on the extensive application of gamma sterilization to a wide range of pharmaceutical components including active pharmaceutical ingredients, excipients, final drug products, and combination drug-medical devices. A summary of the published literature for each class of pharmaceutical compound or product is presented. The irradiation conditions and various quality control characterization methodologies that were used to determine final product quality are included, in addition to a summary of the investigational outcomes. Based on this extensive literature review and in combination with regulatory guidelines and other published best practices, a decision tree for implementation of gamma irradiation for pharmaceutical products is established. This flow chart further facilitates the implementation of gamma irradiation in the pharmaceutical development process. The summary therefore provides a useful reference to the application and versatility of gamma irradiation for pharmaceutical sterilization. Lay abstract: Many pharmaceutical products require sterilization to ensure their safe and effective use. Sterility is therefore a critical quality attribute and is essential for direct injection products. Due to the requirement for terminal sterilization, where possible in the pharmaceutical industry sterilization by gamma irradiation has been commonly used as an effective method to sterilize pharmaceutical products as indicated by its acceptance in the European Pharmacopeia. Gamma sterilization is a very attractive terminal sterilization method in view of its ability to attain 10(-6) probability of microbial survival without excessive heating of the product or exposure to toxic chemicals. However, radiation compatibility of a product is one of the first aspects to evaluate when considering gamma sterilization. Gamma radiation consists of high-energy photons that result in the generation of free radicals and the subsequent ionization of chemical bonds, leading to cleavage of DNA in microorganisms and their subsequent inactivation. This can result in a loss of active pharmaceutical ingredient potency, the creation of radiolysis by-products, a reduction of the molecular weight of polymer excipients, and influence drug release from the final product. There are several strategies for mitigating degradation effects, including optimization of the irradiation dose and conditions. This review will serve to highlight the extensive application of gamma sterilization to a broad spectrum of pharmaceutical components including active pharmaceutical ingredients, excipients, final drug products, and combination drug-medical devices.
The development of space food has been evolving since the Soviet cosmonaut, German Titov, became the first human to eat in space in August 1961. John Glenn was the first American to consume food, applesauce, on the third manned Mercury mission in August 1962. Before these events, there was no knowledge that humans would be able to swallow and, hence, eat in weightlessness. Space food development began with highly engineered foods that met rigid requirements imposed by spacecraft design and short mission durations. Improvements in the habitability of the spacecraft have permitted improvements in the quality of space food. As the missions became longer, the need for better nutrition, more variety, and easily consumable foods also became more important. Currently, the International Space Station astronauts have a wide variety of foods. The goal is to provide acceptable foods that taste similar to foods we eat here on Earth. Extended planetary stays will require even more variety and more technologic advances. Plants will be grown to recycle the air and water and will provide food for the crew. These harvested crops will need to be processed into safe, healthy, and acceptable food ingredients that can then be prepared into menu items.
Consumption of salsas and dishes containing cilantro has been linked to several recent outbreaks of food-borne illness due to contamination with human pathogens. Ionizing irradiation can effectively eliminate food-borne pathogens from various vegetables including cilantro. However, the effect of irradiation on aroma of fresh cilantro is unknown. This study was conducted to investigate the effect of irradiation on volatile compounds of fresh cilantro leaves. Fresh cilantro leaves (Coriandrum sativum L) were irradiated with 0, 1, 2, or 3 kGy Á radiation and then stored at 3 °C up to 14 days. Volatile compounds were extracted using solid-phase microextraction (SPME), followed by gas chromato- graphic separation and mass spectra detection at 0, 3, 7, and 14 days after irradiation. Most of the volatile compounds identified were aldehydes. Decanal and (E)-2-decenal were the most abundant compounds, accounting for more than 80% of the total amount of identified compounds. The amounts of linalool, dodecanal, and (E)-2-dodecenal in irradiated samples were significantly lower than those in nonirradiated samples at day 14. However, the most abundant compounds (decanal and (E)-2- decenal) were not consistently affected by irradiation. During storage at 3 °C, the amount of most aldehydes peaked at 3 days and then decreased afterward. Our results suggest irradiation of fresh cilantro for safety enhancement at doses up to 3 kGy had minimal effect on volatile compounds compared with the losses that occurred during storage.
The Cannabis plant (Cannabis sativa L.) has a long history as a recreational drug, but also as part of traditional medicine in many cultures. Based on the number of publications, it is one of the best-studied plants in the world. The relatively recent discovery of cannabinoid receptors and the human endocannabinoid system has opened up a new and exciting field of research. But despite the pharmaceutical potential of Cannabis, its classification as a narcotic drug has prevented its successful development into modern medicine. Fortunately, the chemistry of Cannabis has been studied in much detail. In particular the psychoactive cannabinoid tetrahydrocannabinol (THC) has received great scientific attention, and much is known about its biological effects and mechanisms of action. Besides an extensive description of the chemistry of the cannabinoids, this chapter also introduces the lesser-known terpenoids, flavonoids, and other constituents of the Cannabis plant. Comprehensive information on a variety of subjects is presented, including chromatographic analytical methods, pharmacokinetics, and structure-activity relationships. The known biological effects of Cannabis constituents are discussed in relationship to the development of modern cannabinoid-based medications. Finally, some practical aspects of working with Cannabis are discussed.