Kevin M G Taylor

University of Central Lancashire, Preston, ENG, United Kingdom

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Publications (43)106.16 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The potential of amphiliphilic chitosan formed by grafting octanoyl chains on the chitosan backbone for pulmonary delivery of levofloxacin has been studied. The success of polymer synthesis was confirmed using FT-IR and NMR, whilst antimicrobial activity was assessed against Pseudomonas aeruginosa. Highly dispersible dry powders for delivery as aerosols were prepared with different amounts of chitosan and octanoyl chitosan to study the effect of hydrophobic modification and varying concentration of polymer on aerosolization of drug. Powders were prepared by spray-drying from an aqueous solution containing levofloxacin and chitosan/amphiphilic octanoyl chitosan. L-leucine was also used to assess its effect on aerosolization. Following spray-drying, the resultant powders were characterized using scanning electron microscopy, laser diffraction, dynamic light scattering, HPLC, differential scanning calorimetry, thermogravimetric analysis and X-ray powder diffraction. The in vitro aerosolization profile was determined using a Next Generation Impactor, whilst in-vitro anti-microbial assessment was performed using MIC assay. Microparticles of chitosan have the property of mucoadhesion leading to potential increased residence time in the pulmonary mucus, making it important to test the toxicity of these formulations. In-vitro cytotoxicity evaluation using MTT assay was performed on A549 cell line to determine the toxicity of formulations and hence feasibility of use. The MTT assay confirmed that the polymers and the formulations were non-cytotoxic. Hydrophobically modifying chitosan showed significantly lower MIC (4 fold) than the commercial chitosan against Pseudomonas aeruginosa. The powders generated were of suitable aerodynamic size for inhalation having a mass median aerodynamic diameter less than 4.5 μm for formulations containing octanoyl chitosan. These highly dispersible powders have minimal moisture adsorption and hence an emitted dose of more than 90% and a fine particle fraction (FPF) of 52%. Powders with non-modified chitosan showed lower dispersibility, with an emitted dose of 72% and FPF of 20%, as a result of high moisture adsorption onto the chitosan matrix leading to cohesiveness and subsequently decreased dispersibility.
    European Journal of Pharmaceutics and Biopharmaceutics 10/2014; · 3.83 Impact Factor
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    ABSTRACT: Curcumin has potent antioxidant and anti-inflammatory properties but poor absorption following oral administration owing to its low aqueous solubility. Development of novel formulations to improve its in vivo efficacy is therefore challenging. In this study, formulation of curcumin-loaded DQAsomes (vesicles formed from the amphiphile, dequalinium) for pulmonary delivery is presented for the first time. The vesicles demonstrated mean hydrodynamic diameters between 170 and 200 nm, with a zeta potential of approximately + 50 mV, high drug loading (up to 61 %) and encapsulation efficiency (90 %), resulting in enhanced curcumin aqueous solubility. Curcumin encapsulation in DQAsomes in the amorphous state was confirmed by X-ray diffraction and differential scanning calorimetry analysis. Existence of hydrogen bonds and cation-π interaction between curcumin and vesicle building blocks, namely dequalinium molecules, were shown in lyophilised DQAsomes using FT-IR analysis. Encapsulation of curcumin in DQAsomes enhanced the antioxidant activity of curcumin compared to free curcumin. DQAsome dispersion was successfully nebulized with majority of delivered dose deposited in the second stage of the twin-stage impinger. The vesicles showed potential for mitochondrial targeting. Curcumin-loaded DQAsomes thus represent a promising inhalation formulation with improved stability characteristics and mitochondrial targeting ability, indicating a novel approach for efficient curcumin delivery for effective treatment of acute lung injury and the rationale for future in vivo studies.
    Molecular Pharmaceutics 05/2014; · 4.57 Impact Factor
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    ABSTRACT: Using latex microspheres as model suspensions, the influence of suspension particle size (1, 4.5 and 10μm) on the properties of aerosols produced using Pari LC Sprint (air-jet), Polygreen (ultrasonic), Aeroneb Pro (actively vibrating-mesh) and Omron MicroAir NE-U22 (passively vibrating-mesh) nebulisers was investigated. The performance of the Pari nebuliser was independent of latex spheres particle size. For both Polygreen and Aeroneb Pro nebulizers, total aerosol output increased when the size of latex spheres increased, with highest fine particle fraction (FPF) values being recorded. However, following nebulisation of 1 or 4.5μm suspensions with the Polygreen device, no particles were detected in the aerosols deposited in a two-stage impinger, suggesting that the aerosols generated from this device consisted mainly of the continuous phase while the dispersed microspheres were excluded and remained in the nebuliser. The Omron nebuliser efficiently nebulised the 1μm latex spheres, with high output rate and no particle aggregation. However, this device functioned inefficiently when delivering 4.5 or 10μm suspensions, which was attributed to the mild vibrations of its mesh and/or the blockage of the mesh apertures by the microspheres. The Aeroneb Pro fragmented latex spheres into smaller particles, but uncontrolled aggregation occurred upon nebulisation. This study has shown that the design of the nebuliser influenced the aerosol properties using latex spheres as model suspensions. Moreover, for the recently marketed mesh nebulisers, the performance of the Aeroneb Pro device was less dependent on particle size of the suspension compared with the Omron MicroAir nebuliser.
    International Journal of Pharmaceutics 11/2013; · 3.99 Impact Factor
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    ABSTRACT: Abstract Paclitaxel was loaded into licensed parenteral nutrition nanoemulsions (Clinoleic® and Intralipid®) using bath sonication, and the stability of the formulations was investigated following storage for two weeks at room temperature or at 4 °C. In general, Clinoleic droplets were smaller than Intralipid droplets, being around 255 and 285 nm, respectively, for blank and freshly loaded emulsions. Regardless of storage temperature, the Clinoleic exhibited a very slight or no increase in droplet size upon storage, whilst the droplet size of the Intralipid emulsion increased significantly. The droplet size of both emulsions was minimally affected by paclitaxel concentration within the range of 0, 1, 3 and 6 mg/ml. The pH of both emulsions markedly decreased upon storage at room temperature, which was possibly attributed to the production of fatty acids resulting from phospholipid hydrolysis. However, at 4 °C, the pH of Clinoleic emulsion was unaffected by storage or paclitaxel concentration while the Intralipid emulsion demonstrated a trend for pH reduction. Both nanoemulsions had a negative zeta potential, with the Clinoleic formulations having the highest charge, possibly explaining the better size stability of this emulsion. Overall, this study has shown that paclitaxel was successfully loaded into clinically licensed parenteral emulsions and that Clinoleic showed greater stability than the Intralipid.
    Pharmaceutical Development and Technology 10/2013; · 1.33 Impact Factor
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    ABSTRACT: The influence of sodium halide electrolytes on aerosols generated from the Aeroneb Pro vibrating mesh nebulizer and the Sidestream air-jet nebulizer has been evaluated. Fluids with a range of concentrations of Na halides (i.e. NaF, NaCl, NaBr and NaI) were used as nebulizer solutions and their effect on aerosol properties such as total aerosol output, fine particle fraction (FPF), volume median diameter (VMD) and predicted regional airway deposition were investigated. For both nebulizers, the inclusion of electrolyte significantly enhanced the aerosol properties compared with HPLC grade (deionized) water. Aerosol output, FPF and aerosol fraction less than 2.15μm were directly proportional to electrolyte concentration. Furthermore, the proportion of aerosols that are likely to deposit in the oropharyngeal region, and the VMD of the droplets were inversely related to the electrolyte concentration for both nebulizers. In general, the inclusion of electrolytes had a greater impact on the aerosol properties of the vibrating-mesh nebulizer. In the Aeroneb Pro, NaI 2.0% (w/v) was the optimum solution as it generated the highest aerosol output, FPF and output fraction below 2.15μm with the lowest VMD and minimal predicted oropharyngeal deposition. This was attributed to the polarizing ability of iodide ions present in the largest quantity at the air-water interface. This study has shown that the Aeroneb Pro vibrating-mesh device demonstrated greatly enhanced aerosol properties when halides were included in the nebulizer solutions.
    International Journal of Pharmaceutics 08/2013; · 3.99 Impact Factor
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    ABSTRACT: To explore the potential of crosslinked chitosan nanoparticles as carriers for delivery of siRNA using a jet nebuliser. Nanoparticles encapsulating siRNA were prepared using an ionic crosslinking technique at chitosan to siRNA weight/weight ratios of 10:1, 30:1 and 50:1. Particles were characterised for their size, charge, morphology, pH stability and siRNA encapsulation efficiency. Gel electrophoresis was used to assess the association and stability of siRNA with nanoparticles, including after aerosolisation using a Pari LC Sprint jet nebuliser. The aerosolisation properties of FITC labelled chitosan nanoparticles were investigated using a two-stage impinger. Cell viability was performed with H-292 cells using a WST-1 assay. Positively charged spherical nanoparticles were produced with mean diameters less than 150nm, at all chitosan to siRNA ratios. Nanoparticles were non-aggregated at the pH of the airways and showed high siRNA encapsulation efficiency (>96%). Complete binding of siRNA to chitosan nanoparticles was observed when the w/w ratio was 50:1. Nebulisation produced Fine Particle Fractions of 54±11% and 57.3±1.9% for chitosan and chitosan:siRNA (10:1 w/w) nanoparticles respectively. The stability of chitosan-encapsulated siRNA was maintained after nebulisation. Cell viability was high (>85%) at the highest chitosan concentration (83μg/ml). The results suggest that crosslinked chitosan nanoparticles have potential for siRNA delivery to the lungs using a jet nebuliser.
    International Journal of Pharmaceutics 07/2013; · 3.99 Impact Factor
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    ABSTRACT: Thermal ink-jet spray freeze-drying (TIJ-SFD) was used to produce inhalable particles of terbutaline sulphate, the aerosolisation properties of which were compared to the commercial Bricanyl® formulation. Scanning electron micrograph images showed the particles to be spherical, highly porous and suitable for aerosolisation from a simple, capsule-based dry-powder device (Cyclohaler®) without the need for additional excipients. Particle size was dependent upon the concentration of solution jetted, as well as the distance between the print head and the surface of the liquid nitrogen. Starting with a 5% (w/v) solution and maintaining this distance at 3cm produced spherical, porous particles of volume median diameter 14.1±0.8μm and mass median aerodynamic diameter (MMAD) 4.0±0.6μm. The fine particle fraction (proportion of aerosol with MMAD≤4.46μm) was 22.9±3.3%, which compared favourably with that of the marketed dry powder inhaler formulation of terbutaline (Bricanyl® Turbohaler®; 25.7±3.8%), tested under the same conditions. These findings show that TIJ-SFD is a useful tool to predict the viability of a DPI formulation during preformulation physicochemical characterisation.
    International Journal of Pharmaceutics 02/2013; 447:165-170. · 3.99 Impact Factor
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    ABSTRACT: The aerosol properties of niosomes were studied using Aeroneb Pro and Omron MicroAir vibrating-mesh nebulizers and Pari LC Sprint air-jet nebulizer. Proniosomes were prepared by coating sucrose particles with Span 60 (sorbitan monostearate), cholesterol and beclometasone dipropionate (BDP) (1:1:0.1). Nano-sized niosomes were produced by manual shaking of the proniosomes in deionized water followed by sonication (median size 236nm). The entrapment of BDP in proniosomes-derived niosomes was higher than that in conventional thin film-made niosomes, being 36.4% and 27.5% respectively. All nebulizers generated aerosols with very high drug output, which was 83.6% using the Aeroneb Pro, 85.5% using the Pari and 72.4% using the Omron. The median droplet size was 3.32μm, 3.06μm and 4.86μm for the Aeroneb Pro, Pari and Omron nebulizers respectively and the "Fine particle fraction" (FPF) of BDP was respectively 68.7%, 76.2% and 42.1%. The predicted extrathoracic deposition, based on the median size of nebulized droplets was negligible for all devices, suggesting all of them are potentially suitable for pulmonary delivery of niosomes. The predicted drug deposition in the alveolar region was low using the Omron (3.2%), but greater using the Aeroneb Pro (17.4%) and the Pari (20.5%). Overall, noisome-BDP aerosols with high drug output and FPF can be generated from proniosomes and delivered using vibrating-mesh or air-jet nebulizers.
    International Journal of Pharmaceutics 01/2013; · 3.99 Impact Factor
  • Abdelbary M A Elhissi, Waqar Ahmed, Kevin M G Taylor
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    ABSTRACT: Particulate-based proliposomes were made by coating sucrose carrier particles with egg phosphatidylcholine (EPC), soya phosphatidylcholine (SPC) or soya phosphatidylcholine with an equimole ratio of cholesterol (SPC:Chol, 1:1). Inhalable multilamellar liposomes were generated from proliposomes in situ within a Pari LC Plus nebulizer by addition of aqueous phase, with no need for prior manual shaking. All proliposome formulations produced high aerosol and phospholipid outputs and were delivered in high fractions to the lower stage of a two-stage impinger. The SPC:Chol (1:1) liposomes tended to accumulate more in the nebulizer because of their greater rigidity, which correlated with the larger size measured at the end of nebulization. The size of aerosol droplets as measured by laser diffraction was similar for all formulations, however, at the sputtering period, the SPC:Chol (1:1) formulation produced large droplets with broadened size distribution. This study has demonstrated a simple approach to delivering high outputs of liposomes using a particulate-based proliposome technology and has shown an evidence of liposome generation from proliposomes within a medical nebulizer.
    Journal of Nanoscience and Nanotechnology 08/2012; 12(8):6693-9. · 1.15 Impact Factor
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    ABSTRACT: Ultradeformable liposomes are stress-responsive phospholipid vesicles that have been investigated extensively in transdermal delivery. In this study, the suitability of ultradeformable liposomes for pulmonary delivery was investigated. Aerosols of ultradeformable liposomes were generated using air-jet, ultrasonic or vibrating-mesh nebulizers and their stability during aerosol generation was evaluated using salbutamol sulphate as a model hydrophilic drug. Although delivery of ultradeformable liposome aerosols in high fine particle fraction was achievable, the vesicles were very unstable to nebulization so that up to 98% drug losses were demonstrated. Conventional liposomes were relatively less unstable to nebulization. Moreover, ultradeformable liposomes tended to aggregate during nebulization whilst conventional vesicles demonstrated a "size fractionation" behaviour, with smaller liposomes delivered to the lower stage of the impinger and larger vesicles to the upper stage. A release study conducted for 2 h showed that ultradeformable liposomes retained only 30% of the originally entrapped drug, which was increased to 53% by inclusion of cholesterol within the formulations. By contrast, conventional liposomes retained 60-70% of the originally entrapped drug. The differences between ultradeformable liposomes and liposomes were attributed to the presence of ethanol or Tween 80 within the elastic vesicle formulations. Overall, this study demonstrated, contrary to our expectation, that materials included with the aim of making the liposomes more elastic and ultradeformable to enhance delivery from nebulizers were in fact responsible for vesicle instability during nebulization and high leakage rates of the drug.
    International Journal of Pharmaceutics 07/2012; 436(1-2):519-26. · 3.99 Impact Factor
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    ABSTRACT: Nucleotides and nucleosides are not only involved in cellular metabolism but also act extracellularly via P1 and P2 receptors, to elicit a wide variety of physiological and pathophysiological responses through paracrine and autocrine signalling pathways. For the first time, we have used an ion-pair reversed-phase high-performance liquid chromatography ultraviolet (UV)-coupled method to rapidly and simultaneously quantify 12 different nucleotides and nucleosides (adenosine triphosphate, adenosine diphosphate, adenosine monophosphate, adenosine, uridine triphosphate, uridine diphosphate, uridine monophosphate, uridine, guanosine triphosphate, guanosine diphosphate, guanosine monophosphate, guanosine): (1) released from a mouse renal cell line (M1 cortical collecting duct) and (2) in human biological samples (i.e., urine). To facilitate analysis of urine samples, a solid-phase extraction step was incorporated (overall recovery rate ≥ 98 %). All samples were analyzed following injection (100 μl) into a Synergi Polar-RP 80 Å (250 × 4.6 mm) reversed-phase column with a particle size of 10 μm, protected with a guard column. A gradient elution profile was run with a mobile phase (phosphate buffer plus ion-pairing agent tetrabutylammonium hydrogen sulfate; pH 6) in 2-30 % acetonitrile (v/v) for 35 min (including equilibration time) at 1 ml min(-1) flow rate. Eluted compounds were detected by UV absorbance at 254 nm and quantified using standard curves for nucleotide and nucleoside mixtures of known concentration. Following validation (specificity, linearity, limits of detection and quantitation, system precision, accuracy, and intermediate precision parameters), this protocol was successfully and reproducibly used to quantify picomolar to nanomolar concentrations of nucleosides and nucleotides in isotonic and hypotonic cell buffers that transiently bathed M1 cells, and urine samples from normal subjects and overactive bladder patients.
    Purinergic Signalling 06/2012; 8(4):741-51. · 2.64 Impact Factor
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    ABSTRACT: Crosslinked chitosan nanoparticles, prepared using ionic gelation, have been successfully formulated into pressurized metered dose inhalers (pMDIs) with potential for deep lung delivery of therapeutic agents. Nanoparticles were prepared from crosslinked chitosan alone and incorporating PEG 600, PEG 1000 and PEG 5000 for dispersion in aerosol propellant, hydrofuoroalkane (HFA) 227. Spherical, smooth-surfaced, cationic particles of mean size less than 230 nm were produced. Nanoparticles were positively charged and non-aggregated at the pH of the airways. Crosslinked chitosan-PEG 1000 nanoparticles demonstrated greatest dispersibility and physical stability in HFA-227, whereas other formulations readily either creamed or sedimented. Following actuation from pMDIs, the fine particle fraction (FPF) for crosslinked chitosan-PEG 1000 nanoparticles, determined using a next generation impactor, was 34.0±1.4% with a mass median aerodynamic diameter of 4.92±0.3 μm. The FPFs of crosslinked chitosan, crosslinked chitosan-PEG 600 and crosslinked chitosan-PEG 5000 nanoparticles were 5.7±0.9%, 11.8±2.7% and 17.0±2.1%, respectively. These results indicate that crosslinked chitosan-PEG 1000-based nanoparticles are promising candidates for delivering therapeutic agents, particularly biopharmaceuticals, using pMDIs.
    European journal of pharmaceutics and biopharmaceutics: official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V 01/2012; 81(1):74-81. · 3.15 Impact Factor
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    ABSTRACT: The use of thermal ink-jet spray freeze-drying (TIJ-SFD) to engineer inhalable, excipient-free salbutamol sulphate (SS) particles was assessed. A modified Hewlett-Packard printer was used to atomise aqueous SS solutions into liquid nitrogen. The frozen droplets were freeze-dried. It was found that TIJ-SFD could process SS solutions up to 15%w/v; the porous particles produced had a physical diameter of ca. 35 μm. Next generation impactor (NGI) analysis indicated that the particles had a smaller aerodynamic size (MMAD ranging from 6 to 8.7 μm). Particles prepared from the lowest concentration SS solution were too fragile to withstand aerosolisation, but the 5%w/v solution yielded particles having the best combination of strength and aerodynamic properties. Comparison with a commercial SS formulation (Cyclocap®) showed that the SFD preparation had an almost equivalent FPF (6.4 μm) when analysed with a twin-stage impinger (TSI; 24.0 ± 1.2% and 26.4 ± 2.2%, respectively) and good performance when analysed with NGI (FPF (4.46 μm):16.5 ± 2.0 and 27.7 ± 1.7, respectively). TIJ-SFD appears to be an excellent method to prepare inhalable particles. It is scalable yet allows assessment of the viability of the pulmonary route early in the development since it can be used with very small volumes (<0.5 mL) of solution.
    European journal of pharmaceutics and biopharmaceutics: official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V 01/2012; 80(1):149-55. · 3.15 Impact Factor
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    ABSTRACT: Proliposomes were made by coating lactose monohydrate (LMH), sucrose or sorbitol particles with phosphatidylcholine. Proliposomes hydrated under static (i.e., no shaking) conditions instantly generated liposomes which deaggregated immediately using sorbitol carrier and over a period of 5 min using LMH or sucrose particles. Manual dispersion of sucrose-based or sorbitol-based proliposomes generated spherical vesicles, whilst vesicles generated from LMH-based proliposomes were rich in elongated “worm-like” structures. The effect of formulation on liposome size was minimal. Overall, carrier type and hydration procedure of proliposomes had a marked effect on liposome morphology whilst formulation had minimal effect on liposome size.
    Journal of Dispersion Science and Technology - J DISPER SCI TECH. 01/2011;
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    ABSTRACT: Whilst some proteins can be effectively administered to the lungs using a nebulizer, others, such as lactate dehydrogenase (LDH) are degraded during air-jet nebulization. In order to deliver LDH by nebulization a protective delivery system or carrier may therefore be appropriate. The aim of this study was to produce and characterize a formulation of LDH, which retains enzyme activity during nebulization. Chitosan, a biocompatible, biodegradable and bioadhesive polysaccharide polymer, was included in the formulations studied as a potential protective agent. Complexes of LDH with chitosan of different molecular weights and concentrations were assessed for size, zeta potential, aerosol droplet size and delivery from a jet nebulizer. The highest molecular weight chitosan had the greatest complex size and a net positive charge of +29.7mV. Jet nebulization resulted in aerosol droplets with median size in the range 2.36-3.52μm. Nebulization of LDH solution resulted in enzyme denaturation and reduced activity. The stability of LDH was greatly improved in formulations with chitosan; with greater than 50% total LDH available in a nebulizer delivered to the lower stage of a two-stage impinger, with up to 62% retained enzyme activity. The nonionic surfactant Tween 80 also improved the stability of LDH to nebulization and had an additive protective effect when included, with chitosan, in formulations. These findings suggest chitosan may be a useful excipient in the preparation of stable protein formulations for jet nebulization.
    International Journal of Pharmaceutics 10/2010; 402(1-2):140-5. · 3.99 Impact Factor
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    ABSTRACT: The aim of this study was to produce and characterise amphotericin B (AmB) containing chitosan-coated liposomes, and to determine their delivery from an air-jet nebuliser. Soya phosphatidylcholine : AmB (100 : 1) multilamellar vesicles were generated by dispersing ethanol-based proliposomes with 0.9% sodium chloride or different concentrations of chitosan chloride. These liposomes were compared with vesicles produced by the film hydration method and micelles. AmB loading, particle size, zeta potential and antifungal activity were determined for formulations, which were delivered into a two-stage impinger using a jet nebuliser. AmB incorporation was highest for liposomes produced from proliposomes and was greatest (approximately 80% loading) in chitosan-coated formulations. Following nebulisation, approximately 60% of the AmB was deposited in the lower stage of the two-stage impinger for liposomal formulations, for which the mean liposome size was reduced. Although AmB loading in deoxycholate micellar formulations was high (99%), a smaller dose of AmB was delivered to the lower stage of the two-stage impinger compared to chitosan-coated liposomes generated from proliposomes. Chitosan-coated and uncoated liposomes loaded with AmB had antifungal activities against Candida albicans and C. tropicalis similar to AmB deoxycholate micelles, with a minimum inhibitory concentration of 0.5 microg/ml. This study has demonstrated that chitosan-coated liposomes, prepared by an ethanol-based proliposome method, are a promising carrier system for the delivery of AmB using an air-jet nebuliser, having a high drug-loading that is likely to be effectively delivered to the peripheral airways for the treatment of pulmonary fungal infections.
    The Journal of pharmacy and pharmacology. 07/2010; 62(7):821-8.
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    ABSTRACT: The aim of this study was to examine the use of continuing professional development (CPD) portfolios by hospital pharmacists. The objectives were to assess the extent to which pharmacists use portfolios in CPD and to examine the attitudes/beliefs which differentiate those who do and do not keep a portfolio. Participants completed two questionnaires: (1) personality traits were examined using the Big-Five questionnaire and (2) a new Pharmacist Portfolio-Engaging Behaviour Questionnaire (PPEBQ) examined the attitudes and beliefs. What constitutes a portfolio was left to the interpretation of the participants, but it was specified that the survey was about participants' views of producing written records of their professional practice for CPD. The setting was hospital pharmacists based in the London area in December 2004. Overall, 134 pharmacists (78%) returned both questionnaires, and 80 stated that they kept a portfolio and 52 stated that they did not (two questionnaires were returned spoilt). There was no significant difference in the age or number of years qualified between those with and without a portfolio. Three personality traits were linked to keeping a portfolio (conscientiousness, agreeableness and emotional stability). Pharmacists with a portfolio scored highly on the perceived behavioural control and behavioural intention scales of the PPEBQ. The Big-Five personality questionnaire is a useful tool to investigate pharmacists' use of a portfolio. Results of the PPEBQ suggested that hospital pharmacists who had a portfolio were concerned with having control over its production. However, the PPEBQ requires further development to improve its reliability. These findings have implications for the educational support of CPD.
    International Journal of Pharmacy Practice 10/2009; 17(5):299-304.
  • Bildad K Nyambura, Ian W Kellaway, Kevin M G Taylor
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    ABSTRACT: Nanoparticles delivered from pressurized metered dose inhalers (pMDIs) potentially offer a means of efficiently delivering proteins to the lung. Nanoparticles containing the model protein lysozyme have been produced using microemulsion and nanoprecipitation methods. Freeze-drying water in oil emulsions, with chloroform as the organic solvent, followed by washing of excess surfactant (lecithin) led to the production of lactose nanoparticles having approximately 300 nm mean size. Substitution of lactose with lysozyme led to a significant increase in the mean size of nanoparticles (645-750 nm). This may have been due to the surface activity of lysozyme which altered the emulsification properties. The retained biological activity of lysozyme increased with increased lactose concentration in the formulation, and approximately 99% biological activity was retained when 20% (w/w) lactose was used. Ethanol used in the formulation in place of chloroform changed the production process from emulsification to nanoprecipitation. A monodisperse system (mean size approximately 275 nm, polydispersity index approximately 0.1) of spherical nanoparticles containing 80% (w/w) bioactive lysozyme (retained activity 99%) was generated. The nanoparticles washed with ethanol containing DPPC, oleic acid or Span 85 (2%, w/v) could readily be dispersed in HFA 134a without further processing, and a stable suspension was formed. Lysozyme remained stable (retained biological activity 98%) even after the nanoparticles were suspended in HFA 134a. This indicates the potential of nanoparticles for delivery of proteins from HFA-based pressurized metered dose inhaler formulations.
    International Journal of Pharmaceutics 06/2009; 372(1-2):140-6. · 3.99 Impact Factor
  • Bildad K Nyambura, Ian W Kellaway, Kevin M G Taylor
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    ABSTRACT: Nanoparticles containing insulin have been produced by emulsification processes followed by freeze-drying. Purified nanoparticles were suspended in hydrofluoroalkane (HFA) 134a, using essential oils (cineole and citral) as suspension stabilizers to form pressurized metered dose inhaler (pMDI) formulations. The retention of insulin integrity after formulation processing was determined using high performance liquid chromatography (HPLC), size exclusion chromatography (SEC), circular dichroism (CD) and fluorescence spectroscopy. The results indicated that the native structure of insulin was retained after formulation processing. Aerosolization properties of the manufactured pMDI formulations were determined using a multi-stage liquid impinger. The results showed that the nanoparticles were suitable for peripheral lung deposition, with a fine particle fraction (FPF(<1.7 microm)) of approximately 45% (w/w). In conclusion, the pMDI formulations with nanoparticles containing insulin developed in this study have the potential to deliver protein therapeutics via inhalation for systemic action.
    International Journal of Pharmaceutics 06/2009; 375(1-2):114-22. · 3.99 Impact Factor
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    ABSTRACT: The aim of this study was to undertake an in-depth investigation of the influence of continuing professional development (CPD) portfolios on pharmacy practice in the hospital setting. The objectives were to explore the views of pharmacists regarding the contribution of CPD records to professional practice and examine the influence of time and experience on pharmacists' views of recording professional practice. A qualitative design was used to explore the views of pharmacists over 12 months. Pharmacists were stratified according to years of practice in the UK National Health Service (NHS). The methods used involved semi-structured in-depth face-to-face interviews. The interviews were undertaken at three time points. The pharmacists were gathered into three focus groups to test the consistency of the interviews. A purposive sampling method used nine NHS Teaching and Non-Teaching hospital pharmacists in the London area. The participants included four males and five females, who had been qualified for between 0.1 and 21 years. Three key themes emerged for how CPD records contribute to practice: (1) lack of contribution to practice, (2) tacit contribution and (3) mentality. Overall, the recording process made little if any change in professional practice. The more experienced participants were less likely to be able to explain any changes in practice and there were no consistent changes in the views expressed over time. The contribution of CPD recording to enhancing practice in hospital pharmacists was difficult to demonstrate. This study has also illustrated the power relationships involving control mechanisms used by the NHS, and the UK pharmacists' regulatory body, which are discussed in the context of the Panopticon model of self-regulated behaviour. Further research is needed to establish the value of CPD recording.
    International Journal of Pharmacy Practice 04/2009; 17(2):107-13.

Publication Stats

272 Citations
106.16 Total Impact Points

Institutions

  • 2012–2013
    • University of Central Lancashire
      • Institute of Nanotechnology and Bioengineering
      Preston, ENG, United Kingdom
  • 2008–2012
    • The School of Pharmacy
      • Pharmaceutics
      Londinium, England, United Kingdom
  • 1989–2010
    • University of London
      • The School of Pharmacy
      London, ENG, United Kingdom
  • 2009
    • Guy's and St Thomas' NHS Foundation Trust
      • Pharmacy
      Londinium, England, United Kingdom
  • 1994
    • The Kings College
      Brunswick, Ohio, United States