Igor Clarot

Igor Clarot
University of Lorraine | UdL · CITHEFOR - Cibles Thérapeutiques, Formulation et Expertises Pré-Clinique du Médicament

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57
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793
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Publications

Publications (57)
Article
Food-processing and pharmaceutical industries share a lot of stability issues against the same physical, chemical, and microbiological phenomena. They also share some solutions to improve the stability as the use of preservatives and packaging. Ecological concerns lead to the development of tremendous innovations in food. Some of these innovations...
Article
Objectives Azacitidine is a pyrimidine nucleoside analogue whose stability is temperature dependent. Numerous publications have studied the stability of this drug with discordant results. The purpose of this work is to study the stability of azacitidine suspensions under different conditions to allow preparation in advance: vials stored at room tem...
Article
Thiols are very important molecules in the biomedical field involved for example in redox homeostasis. Their detection and quantification remain difficult due to their poor stability (oxidation) linked to their strong reactivity towards other thiols (by the formation of S-S bonds) or other interfering molecules in the medium. Cellulose membranes wi...
Article
An overview on the design of nitric oxide (NO) delivering surfaces for biomedical purposes is provided, with a focus on the advances of the past 5 years. A localized supply of NO is of a particular interest due to the pleiotropic biological effects of this diatomic compound. Depending on the generated NO flux, the surface can mimic a physiological...
Article
Full-text available
Many scientific endeavors are dependent upon the accurate quantification of drugs and endogenous substances, such as pharmacokinetics [...]
Article
The cyanobacterium Arthrospira platensis, spirulina, is a source of pigments such as phycobiliprotein, phycocyanin. Phycocyanin is used in the food, cosmetic, and pharmaceutical industries because of its antioxidant, anti-inflammatory, and anticancer properties. The different steps involved in extraction and purification of this protein can alter t...
Article
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There is intensive research using gold nanoparticles for biomedical purposes, which have many advantages such as ease of synthesis and high reactivity. Their possible small size (<10 nm) can lead to the crossing of biological membranes and then to problematic dissemination and storage in organs that must be controlled and evaluated. In this work, a...
Article
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In nanomedicine, hybrid nanomaterials stand out for providing new insights in both the diagnosis and treatment of several diseases. Once administered, engineered nanoparticles (NPs) interact with biological molecules, and the nature of this interaction might directly interfere with the biological fate and action of the NPs. In this work, we synthes...
Article
Covalent organic frameworks (COFs) are a class of porous materials with high surface area, high porosity, good stability and tunable structure that have been widely used in the separation area. In this work, we have proposed the in situ synthesis of a novel COF composed of 4,4',4''-(1,3,5-triazine-2,4,6-triyl)trianiline (Tz) and 1,4-dihydroxytereph...
Article
Full-text available
The design of layer-by-layer (LbL) polyelectrolyte films including nanoparticles is a growing field of innovation in a wide range of biomedical applications. Gold nanoparticles (AuNPs) are very attractive for further biomolecule coupling to induce a pharmacological effect. Nanostructured LbL films coupled with such metallic species show properties...
Article
Gold nanoparticle (AuNP) interaction with the blood compartment as a function of their charge and the binding energy of their surface ligand was explored. Citrate, polyallylamine and cysteamine stabilized AuNP along with dihydrolipoic acid and polyethylene glycol capped AuNP were synthesized and fully characterized. Their interactions with model pr...
Article
p>ABSTRACT Background: In severe infections, high-concentration vancomycin may be administered by continuous infusion. The dosage of vancomycin may reach 60 mg/kg per day. Objectives: To study the feasibility of preparing high-concentration vancomycin solutions (40 to 83.3 mg/mL), to study the effect of an electric syringe pump on the physical st...
Article
Nanoparticles are being developed for a wide range of medical applications such as, controlled release, drug delivery systems or imagery, theranostics, implants…. For the moment, there is no legal definition of nanoparticles or nanomaterials for therapeutic use. The specific case of gold nanoparticles is not an exception: their current definition a...
Article
Introduction Nefopam has been reported to be effective in postoperative pain control with an opioid-sparing effect, but the use of nefopam can lead to nausea and vomiting. To prevent these side effects, droperidol can be mixed with nefopam. In intensive care units, high concentrations of nefopam and droperidol in syringes can be used with a continu...
Article
The development of new packaging able to preserve sensitive biomolecules against oxidative stress is an important field. Several studies refer to antioxidant properties carried out by colloidal gold nanoparticles (AuNP). Herein, the purpose was to check whether this property is preserved when AuNP are immobilized on a glass support. After nanostruc...
Article
Objectives Norepinephrine is usually used in emergency situations such as in intensive care units (ICUs) for the restoration of blood pressure. The objective was to study the stability of highly-concentrated solutions of norepinephrine at 0.50 mg/mL and 1.16 mg/mL, diluted in glucose 5% (G5%) in polypropylene syringes, protected or not from light,...
Article
Many novel medical devices (implantable or not) include nanomaterials through either surface-coating by nanoparticles or by direct nanostructuration of the surface. In this review we have identified several medical devices currently on the market in various health domains (wound healing, prevention or treatment of infectious diseases, cardio-vascul...
Article
Nitrogen and its numerous hydrogenated and oxygenated derivatives are of main importance in our environment and in living cells as well in both qualitative and quantitative aspects. Their monitoring is needed to evaluate all disturbances occurring in the nitrogen cycle and in pathophysiological events related to variations of nitric oxide (NO) bioa...
Article
S-nitrosothiols, a class of NO donors, demonstrate potential benefits for cardiovascular diseases. Drugs for such chronic diseases require long term administration preferentially through the oral route. However, the absorption of S-nitrosothiols by the intestine, which is the first limiting barrier for their vascular bioavailability, is rarely eval...
Article
Full-text available
Which scientist has never heard of glutathione (GSH)? This well-known low-molecular-weight tripeptide is perhaps the most famous natural antioxidant. However, the interest in GSH should not be restricted to its redox properties. This multidisciplinary review aims to bring out some lesser-known aspects of GSH, for example, as an emerging tool in nan...
Article
A simple isocratic HPLC method using visible detection was developed and validated for the quantification of gold in nanoparticles (AuNP). After a first step of oxidation of nanoparticles, an ion-pair between tetrachloroaurate anion and the cationic dye Rhodamine B was formed and extracted from the aqueous media with the help of an organic solvent....
Article
Full-text available
Purpose: In a previous work, we have synthetized a new dinitrosothiol, i.e. S,S'-dinitrosobucillamine BUC(NO)2 combining S-nitroso-N-acetylpenicillamine (SNAP) and S-nitroso-N-acetylcysteine (NACNO) in its structure. When exposed to isolated aorta, we observed a 1.5-fold increase of (•)NO content and a more potent vasorelaxation (1 log higher pD2)...
Article
The LR12 peptide has been reported to reduce the size of infarct and improve both cardiac function and survival in myocardial infarction in murine models, after daily repeated intraperitoneal injections. In order to protect peptide from degrading and to prolong its release, in situ implants based on biocompatible biodegradable polymers were prepare...
Article
A simple, sensitive, selective and robust HPLC method based on intrinsic fluorescence detection was developed for the quantitation of a dodecapeptide (designated as LR12), inhibitor of Triggering Receptor Expressed on Myeloid cells-1 (TREM-1), in rat whole blood. Sample treatment was optimized using protein precipitation and solid phase extraction....
Article
Surface material functionalization including layer-by-layer (LbL) polyelectrolyte films with incorporated nanoparticles is a growing field with a wide range of biomedical applications: drug reservoirs, medical devices, or tissue engineering. In parallel, gold nanoparticles (AuNPs) can be grafted by drugs and sensitive molecules using simple protoco...
Article
Gold nanoparticles (AuNP) are one of the most widely applied nanomaterials for biomedical purposes due to their ease of preparation,well-defined structure and simple surface functionalization. Herein, a method to anchor reduced glutathione (GSH, i.e. an important antioxidant tripeptide in all living organisms) onto AuNP surface with preservation of...
Article
The antibacterial tetracationic tetra-p-guanidinoethylcalix[4]arene developed by our team has been anchored through bottom-up or top-down pathways to the surface of Merrifield and Wang benzaldehyde resins; the attachment involved either a pyridinium linker or an imine/amine one. The grafting yields were evaluated by elemental analysis through the n...
Article
Four kinds of gold nanoparticles (AuNP) quite similar in terms of gold core size (ca. 5nm) and shape (spherical) but differing by their surface chemistry (either negatively, or positively charged, or neutral) were synthesized. They were analyzed using both the classical physicochemical approach (spectrophotometry, dynamic light scattering coupled o...
Poster
Full-text available
This poster presentation dealt with the screening and purification of Metal Chelating Peptides in Hydrolysates for their Antioxidant Properties.
Article
Full-text available
It has been shown that diverse strains of bacteria can be separated according to their characteristic surface properties by means of capillary electrophoresis (CE). We employed here this analytical technique to the study of colistin-resistance in Gram-negative bacteria, which involves the selection of mutants with modified outer membrane compositio...
Article
The poly-cationic pyridinium-Merrifield resin I was prepared and characterized by elemental analysis, infrared spectroscopy and SEM, with a loading of 2.96 � 10�3 mol of pyridinium chloride groups per gram. Its sequestering properties towards bacteria were evaluated, using E. coli as a model. The capture of E. coli was followed by Capillary Electro...
Article
S-nitrosoglutathione (GSNO) is one of low molecular weight S-nitrosothiols occuring in humans. Nowadays, it is widely used as a nitric oxide donor for in vitro, ex vivo and in vivo experiments related to the investigation of its pathophysiological role as well as in clinical trials, aimed at its potential therapeutic use. Despite numerous reports o...
Article
We analyze the structure, hydration, and pKa values of p-guanidinoethyl- phenol through a theoretical study. These issues are relevant to understand the mechanism of action of the tetrameric form, the antibacterial compound tetra-p-guanidinoethyl-calix[4]-arene (Cx1). The p-guanidinoethyl-phenol monomer (mCx1) has two ionizable groups. One importan...
Article
Cyclodextrins (CyDs) currently displays even today the image of a natural macrocyclic compound largely dominant in the formation of inclusion complexes with small hydrophobic molecules. During the past 10years, advances in this field allowed to achieve more and more sophisticated CyDs derivatives opening a simple access in scale-up quantities to or...
Article
Full-text available
Two tetra-p-tert-butyl-calix[4]arene species bearing one or two anti-HSV aciclovir units tethered via carbodiester linkages at the lower rim were synthesized as possible antiviral prodrugs. The amphiphilic properties of these derivatives were studied using Langmuir balance at the air–water and air–carbonate buffer interfaces; the monolayers formed...
Article
We analyze the structure, hydration, and pK(a) values of p-guanidinoethyl-phenol through a combined experimental and theoretical study. These issues are relevant to understand the mechanism of action of the tetrameric form, the antibacterial compound tetra-p-guanidinoethyl-calix[4]arene (Cx1). The investigated system can also be useful to model oth...
Article
Full-text available
Hydroxy pentacyclic triterpenoic acids (HPTAs) have been described to exhibit numerous pharmacological properties. They also exhibit poor hydrosolubility, thus affecting their potential clinical interest. The association of these active substances with cyclodextrins could be employed to improve some properties such as bioavailability and activity....
Article
The selective extraction of silver(I) and zinc(II) species from ternary mixtures involving lead(II) as the main component was performed using a Wang benzaldehyde resin supported calixarene–bipyridyl ligand. The extraction efficiency and selectivity was evaluated and quantified by complexation experiments using ionic liquid chromatography. Silver an...
Article
Full-text available
Two tetra-p-tert-butyl- and two tetra-p-H-calix[4]arene species integrating one or two propylnalidixate esters at the lower rim have been synthesized as possible antibacterial prodrugs. As they display amphiphilic behavior, their properties at the air–water interface were evaluated using the Langmuir balance technique. It has been shown that the tw...
Article
A new chelating calix[4]arene derivative incorporating two bipyridyl groups and one primary amino attachment function at the lower rim has been synthesised and coupled to Wang benzaldehyde resin. The new material effectively displayed complexation abilities towards Cu(I) and Zn(II) transition metal cations. The grafting efficiency was evaluated and...
Article
Full-text available
Water-soluble, thiol protected cadmium telluride CdTe quantum dots (QDs) exhibit size dependent excitation/emission wavelength tunability. The heating period ensuring the growth of CdTe nanocrystals capped with thioglycolic acid (CdTe@TGA) in aqueous solution is critical to reach a required/desirable diameter. Thus, reaction medium was monitored us...
Article
A water-soluble calixarene-based heterocyclic podand incorporating a quinolone antibiotic subunit, the nalidixic acid, was synthesised and fully characterised. Its prodrug behaviour was assessed in vitro by HPLC, demonstrating the release of the tethered quinolone in model biological conditions. Microbiological studies performed on various Gram-pos...
Article
A rapid and simple method for the simultaneous determination of tobramycin and colistin sulphate in a pharmaceutical formulation by reversed phase HPLC and evaporative light scattering detection is described. Chromatographic separation was carried out in gradient mode using a Zorbax SB C18 column (150mmx4mm, 3.5microm) with mobile phases of acetoni...
Article
The facile synthesis of a novel bis-(guanidinium)-tetrakis-(beta-cyclodextrin) tetrapod, the first example of a new host family, was described, and the ability of the cyclodextrin CyD tetrapod to form molecular association with siRNA and DNA guest molecules was demonstrated. Affinity capillary electrophoresis was used to determine the binding const...
Article
Near InfraRed Spectroscopy (NIRS) is a potentially powerful tool for assessing the homogeneity of industrial powder blends. In the particular context of hospital manufacturing, we considered the introduction of the technique at a small pharmaceutical process scale, with the objective of following blend homogeneity in mixtures of seven components. T...
Article
Full-text available
Thanks to the recent technological advancements, evaporative light-scattering detection (ELSD) is regarded as a valuable alternative to UV detection for liquid chromatographic analysis of substances that do not contain a chromophore. In the field of substances for pharmaceutical use, LC-ELSD appears to be suitable for aminoglycosides, most of which...
Article
Terpene compounds include a wide variety of molecules with very different structures and physico-chemical properties. Monoterpenes are of interest because of their volatility and aromatic properties. Inclusion complexation of these molecules with cyclodextrins will lead to chemical and volatility protection and to a possible controlled release. In...
Article
A rapid and simple method for the determination of main components and related substances of both neomycin sulfate and framycetin sulfate by HPLC and evaporative light scattering detection (ELSD) is described. The method was also used to determine the neomycin B and the sample sulfate content. Detection and quantitation of aminoglycoside antibiotic...
Article
A rapid and simple method for the separation and quantitation of gentamicin sulfate by HPLC coupled with evaporative light scattering detection (ELSD) has been developed. Detection of the different components of gentamicin is problematic because of the lack of UV absorbing chromophore. The use of the universal ELSD avoids the need for sample deriva...
Article
Specific programming of automated HPLC systems allows total on-line qualification, validation and stability monitoring using the concept of deferred standards. Setting up such a process for routine analyses in an automated HPLC system requires specific autosampler programming as well as specific monitoring software. With an autosampler, a double in...
Article
The effect of temperature on the retention of terpene derivatives on a porous graphitic carbon stationary phase has been investigated with methanol-water mobile phases containing β-cyclodextrin. Changes in Van't Hoff plots were evaluated in relation to the β-cyclodextrin concentration. Thermodynamic data were determined for both (i) solute transfer...
Article
The stoichiometric coefficients and apparent formation constants (Kf) of alpha-terpineol, thymol, geraniol and linalool complexes with beta-cyclodextrin (beta-CD) were determined using HPLC with a porous graphitic carbon (PGC) chromatographic support. Measurements were performed with four different methanol-water mobile phases. All the terpene deri...
Article
Full-text available
The retention behavior of natural α-, β-, and γ-cyclodextrins on a porous graphitic carbon (PGC) stationary phase is investigated. Unusual retention properties for reversed-phase chromatographic conditions are observed with acetonitrile—methanol and water—methanol mixtures as mobile phases. It is assumed that the retention process is governed not o...
Article
Sedimentation field-flow fractionation (SdFFF) instrumentation is now mature. Methodological procedure and particle separation development rules are well established even in the case of biological species. However, in some biological applications, retention properties of samples not predicted by any field-flow fractionation (FFF) elution models are...
Article
Full-text available
Field-flow fractionation (FFF) is an analytical technique particularly suitable for the separation, isolation, and characterization of macromolecules and micrometer- or submicrometer-sized particles. This chromatographic-like methodology can modulate the retention of micron-sized species according to an elution mode described to date as "steric hyp...

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