Effect of Autoclaving on the Physicochemical Properties and Biological Activity of Aluminum Oxyhydroxide Used as an Adjuvant in Vaccines.

The long-term biodistribution of non-biodegradable microstructures or nanostructures used in vaccinations is widely unknown. This is the case for aluminum oxyhydroxide, the most widely used vaccine adjuvant, which is a nanocrystalline compound that spontaneously forms nanoprecipitates. Although generally well-tolerated, aluminum oxyhydroxide is detected in macrophages a long time after vaccination in individuals predisposed to the development of systemic and neurological aspects of the autoimmune (inflammatory) syndrome induced by modified adjuvant. In the present study, we established that the terminal sterilization of aluminum oxyhydroxide by autoclaving in final container vials produced measurable changes in its physicochemical properties. Moreover, we found that these changes included (1) a decreasing in the pH of aluminum oxyhydroxide solutions, (2) a reduction in the adsorption capacity of bovine serum albumin, (3) a shift in the angle of X-ray diffraction, (4) a reduction in the lattice spacing, causing the crystallization and biopersistence of modified aluminum oxyhydroxide in the macrophage, as well as in muscle and the brain.

Development and validation of HPLC method for simultaneous quantification of alpha-tocopherol (free or encapsulated) and cholesterol in semen cryopreservation media.

The HPLC method was developed and validated for assaying alpha-tocopherol and cholesterol in cryopreservation media. Chromatographic separation was performed on an isocratic system, using a C-18 column. The mobile phase was composed of a mixture of methanol:acetonitrile:water 68:28:4 (v/v/v), using a flow rate of 1.5 mL/min and 20 µL injection volume, at a wavelength of 208 nm. The method was validated according to International Conference on Harmonization guidelines. The method proved to be specific, accurate, precise, and linear with correlation coefficients greater than 0.996 over a wide concentration range of both analytes. Vitamin E and cholesterol presented limits of detection of 0.002 mg/mL, 0.026 mg/mL and limits of quantitation of 0.006 mg/mL, 0.086 mg/mL, respectively. This method is simple and rapid, shows high precision and accuracy, and offers the advantage of simultaneous assaying of vitamin E and cholesterol (alone, in cyclodextrins complexes or in liposome loaded) on semen cryopreservation media.

Amorphous solid dispersion studies of camptothecin-cyclodextrin inclusion complexes in PEG 6000.

Abstract: The present work focused on the solubility enhancement of the poorly water-soluble anti-cancer agent camptothecin which, in its natural state, presents poor solubility inducing lack of activity with a marked toxicity. A new approach is adopted by using a ternary system including camptothecin (CPT) and cyclodextrins (CDs) dispersed in polyethylene glycol (PEG) 6000. Camptothecin solubility variations in the presence of α-CD, ß-CD, γ-CD, hydroxypropyl-α-CD (HPα-CD), hydroxypropyl-ß-CD (HPß-CD), permethyl-ß-CD (PMß-CD) and sulfobutyl ether-ß-CD (SBEß-CD), were evaluated by Higuchi solubility experiments. In the second part, the most efficient camptothecin/P-CDs binary systems, mainly HPß-CD and PMß-CD, were dispersed in PEG 6000. In addition to a drug release and modeling evaluation, the CPT interactions with CDs and PEG 6000 to prepared the amorphous solid dispersion in the binary and ternary systems were investigated by Fourier transformed infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analyses (TGA) and X-ray powder diffraction (XRPD). The results showed that HPß-CD and PMß-CD were the most efficient for camptothecin solubilization with highest apparent equilibrium constants. Dissolution studies showed that percentage of CPT alone after two hour in 0.1 M HCI medium, did not exceed 16%, whereas under the same conditions, CPT/PMß-CD complex reached 76%. When dispersing the binary systems CPT/ß-CDs in PEG 6000, the velocity and the percentage of CPT release were considerably improved whatever the CD used, reaching the same value of 85%. The binary and ternary systems characterization demonstrated that CPT inclused into the CDs cavity, replacing the water molecules. Furthermore, a drug transition from crystalline to amorphous form was obtained when solid dispersion is realized. The present work demonstrated that ternary complexes are promising systems for CPT encapsulation, and offer opportunities to use non toxic and commonly solubilizing carriers: ßCD and PEG 6000 to improve bioavailability.

Removal Efficiency of Insoluble ß-Cyclodextrin Polymer from Water-Soluble Carcinogenic Direct Azo Dyes.

A batch system was applied to study the adsorption of three dyes (methyl violet, eriochrom black T and helianthin) from aqueous solution onto ß-cyclodextrin polymer, synthesized by using citric acid as a cross linking agent. This polymer lets to adsorb only methyl violet for this effect, several operator variables was checked only with this kind of dye, the removal efficiently increases with increase in adsorbent amount; elevation of temperature lets also to improve the dye adsorption; ionic strength has not effect on dye adsorption process, for the pH we have remarked a slight decrease in removal efficiently with increasing of pH values. Equilibrium study was investigated by applying three models (Langumir, Frendlich and Temkin), results show that Langumir isotherm is the appropriate model. FTIR spectra show the complex inclusion formation which dominates the adsorption mechanism, confirmed by the absence of characteristic peaks of methyl violet in ß-cyclodextrin after adsorption.

Identification of tiagabine degradation products using liquid chromatography with electrospray ionization multistage mass spectrometry and ultra-performance liquid chromatography/high-resolution mass spectrometry.

RATIONALE: Tiagabine hydrochloride monohydrate drug substance (TGB) is an antiepileptic agent effective in the treatment of seizure disorders. The stability of TGB was studied and its degradation products were identified for the first time. METHODS: TGB was heated in the presence of H(2)O(2). Degradation products were analyzed by liquid chromatography coupled to electrospray ionization multistage mass spectrometry (LC/ESI-MS(n)) and high-resolution mass spectrometry (HR-MS). RESULTS: This study showed that TGB was degraded by oxidative pathways involving attack of oxygen at different centers but mainly at the double bond of the molecule. The oxidative cascade reactions initiated by the epoxidation of the double bond of tiagabine led to dihydroxy, ketohydroxy and ketone derivatives as well as bisthiophene ketone. CONCLUSIONS: Nine degradation products of TGB were identified. Some diagnostic MS/MS product ions, characteristic of the piperidine or thiophene moiety, were highlighted.

New Formulation and Evaluation of Camptothecin Encapsulated and/or Dispersed Suppository.

BACKGROUND: Camptothecin is known for its potent anticancer activity. However, its optimal activity is reduced due to its low solubility and stability in biological media. OBJECTIVE: The aim of the present study is to design and characterize a Camptothecin (CPT) suppository formulation. METHODS: Rectal suppositories of camptothecin alone, encapsulated with Cyclodextrin (CD) and in the ternary system (CPT encapsulated with cyclodextrin and dispersed in Polyethylene Glycol (PEG) 6000) were prepared using various hydrophobic and hydrophilic polymeric bases as semi-synthetic glyceride (Suppocire® AM Pellets) and Polyethylene Glycols (PEGs) mixtures. Formulations were evaluated by various parameters like weight variation, drug content, hardness and liquefaction time. In vitro release study was performed in USP type I apparatus using phosphate buffer pH 7.2 as dissolution media. RESULTS: Suppositories were within the permissible range of all physical parameters. In vitro drug released from water soluble base (PEG) was greater than that from oil soluble base with ninety percent (90%) of drug dissolution. It was also established that drug release from various formulations was by diffusion mechanism, according to the Higuchi's equation. CONCLUSION: This new formulation offers a new approach to colorectal cancer treatment by offering an alternative and simple drug administration route.

Syndromic Surveillance of Acute Gastroenteritis Using the French Health Insurance Database: Discriminatory Algorithm and Drug Prescription Practices Evaluations.

The French national public health agency (Santé publique France) has used data from the national health insurance reimbursement system (SNDS) to identify medicalised acute gastroenteritis (mAGE) for more than 10 years. This paper presents the method developed to evaluate this system: performance and characteristics of the discriminatory algorithm, portability in mainland and overseas French departments, and verification of the mAGE database updating process. Pharmacy surveys with certified mAGE from 2012 to 2015 were used to characterise mAGE and to estimate the sensitivity and predictive positive value (PPV) of the algorithm. Prescription characteristics from these pharmacy surveys and from 2014 SNDS prescriptions in six mainland and overseas departments were compared. The sensitivity (0.90) and PPV (0.82) did not vary according to the age of the population or year. Prescription characteristics were similar within all studied departments. This confirms that the algorithm can be used in all French departments, for both paediatric and adult populations, with stability and durability over time. The algorithm can identify mAGE cases at a municipal level. The validated system has been implemented in a national waterborne disease outbreaks surveillance system since 2019 with the aim of improving the prevention of infectious disease risk attributable to localised tap water systems.

Cyclodextrin polymers as efficient solubilizers of albendazole: complexation and physico-chemical characterization.

The inclusion behavior of natural cyclodextrins (CDs) and polymers based on natural cyclodextrins (CD-polymer), in solution and in solid-state, was studied towards a poorly water-soluble anti-helminthic drug, albendazole (ABZ), chemically methyl[5-(propylthio)-1-H-benzimidazol-2yl]carbamate. Drug-cyclodextrin solid systems were prepared by freeze-drying. Phase solubility study was used to evaluate the interaction in solution, between ABZ/(CDs) and ABZ/CD-polymers. The stability constants of ABZ/natural CDs and ABZ/CD-polymers complexes were calculated by phase solubility method. The apparent solubility of Albendazole was enhanced especially with poly alpha-CD. The formation of inclusion complexes with natural CDs and polymers of cyclodextrin in the solid-state form were confirmed by Fourier Fransform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR).

Sinefungin-PLGA nanoparticles: drug loading, characterization, in vitro drug release and in vivo studies.

Cryptosporidiosis, the leading cause of endemic and epidemic diarrhoeal disease worldwide is due to Cryptosporidium parvum, a spore-forming protozoan. Anticryptosporidial pharmacological and/or immunological agents were initially tested in immunodeficient models of cryptosporidiosis, and sinefungin exhibited a significant dose dependent curative and preventive activity. Shedding relapses observed after discontinuation of sinefungin therapy lead to identify the bile ducts as a protected reservoir that may sustain chronic infection. The MIC50 of the sinefungin observed in vitro studies is 14.5 microg/ml. It is a hydrophilic drug lowly absorbed when orally administered and nephrotoxic after IV injection. To avoid this toxic effect, Neal's team prepared sinefungin loaded microspheres and proved that encapsulated sinefungin was 10 times more effective than free sinefungin. This optimistic result led us to study the nanoparticles as drug carrier for sinefungin. In this study, we prepared optimal sinefungin loaded PLGA nanoparticles. Physico-chemical characterization, in vitro drug release and in vivo studies were assessed. Negative surface-charged (-56.1 mV) sinefungin loaded PLGA nanoparticles were prepared with a homogenous size of 200 nm. Optimal formulation led to a drug content of 9.18% w/w (4.59 mg) and a drug entrapment of 15.16%. Dilution technique was used to study the release of sinefungin in vitro. 93.03% of sinefungin were released from dilution 1:5 to 1:20. This burst effect could probably due to the adsorption of the drug on the surface of the nanoparticles. A second step with a lower release was observed from dilution 1:20 to 1:100 which may correspond to the diffusion out of the drug solution from the nanoparticles into the bulk release medium. Investigations in rats showed that only 1.23 mg of sinefungin loaded in PLGA nanoparticles led to a decrease of sinefungin in the urine (0.23 mg vs. 4.27 mg for IV administration of free sinefungin) and to an increase of sinefungin concentration in the bile (6.63 microg/ml vs. 3.89 microg/ml for IV administration of free sinefungin). But the biliary concentration of encapsulated sinefungin (6.63 microg/ml) is still nearly 2 times lower than the MIC50.

Investigations on topically applied vitamin A loaded amphiphilic cyclodextrin nanocapsules.

A new cholesteryl-cyclodextrin derivative, obtained by grafting a single cholesterol on a cyclodextrin, was proved suitable for the manufacture of nanocapsules. The chemical structure of Chol-betaCD-Ac was assessed using high resolution 1H-NMR. These nanocapsules were loaded with a lipophilic drug, i.e., vitamin A propionate (PRVA) which is a highly unstable and poorly water soluble molecule with a real interest in therapeutic. The oily nature of vitamin A propionate leads to the formation of nanocapsules with a reproductible size distribution and a long term stability. The colloidal suspension can be used to form a gel which allow to achieve penetration in the skin of the PRVA encapsulated.

New Polymer Inclusion Membrane Containing ß-Cyclodextrin Polymer: Application for Pharmaceutical Pollutant Removal from Waste Water.

We present herein the preparation of novel polymer inclusion membranes (PIMs) containing insoluble ß-CD polymer as a carrier, polyvinyl chloride as a base polymer, and dibuthylphtalate (DBP) as a plasticizer in varying proportions. The prepared PIMs can be obtained by a simple, fast, and high-yield preparation process. Physicochemical characterizations of such membranes occurred in a homogeneous structure. In addition, Fourier-transform infrared Spectroscopy (FT-IR) analysis found that DBP was inserted between these polymeric chains by non-covalent interactions. This led to a spacing of PVC/poly(ß-cyclodextrin) chains inducing a better access of guest molecules to PIM cyclodextrins. To achieve the elimination of ibuprofen and progesterone, two examples of emerging environmental contaminants that can lead to possible alterations to aquatic environments and affect human health, the effect of three operating parameters was studied (pH, the proportion of ß-cyclodextrin polymer, and wastewater agitation). The proportion of ß-cyclodextrin polymer and wastewater agitation had a favorable influence on drug extraction at 10 ppm. The PIMs containing ß-cyclodextrin polymer was unstable in basic conditions and was more effective at acidic pH. These initial results demonstrate the high potential for drug extraction of this polymer.

Effect of iontophoresis and penetration enhancers on transdermal absorption of metopimazine.

BACKGROUND: Metopimazine is an antiemetic drug already used by oral and rectal administration. It would be interesting to develop a new formulation for a transdermal administration. OBJECTIVE: The objective of this study was to determine the influence of iontophoresis on the metopimazine transdermal absorption and the possible synergistic enhancement with chemical enhancers. METHODS: Transdermal transport of metopimazine was studied in vitro in a Franz cell with pig skin according to the following protocol: 1h of iontophoresis followed by 7h of passive diffusion. Different current densities were applied: 0, 0.125, 0.25 and 0.5 mA/cm(2). Chemical enhancers used as solvent dilution were ethanol, propylene glycol and isopropyl myristate. Metopimazine was assayed by HPLC. Fourier transform infrared spectroscopy was used to determinate the interaction between chemical enhancers and stratum corneum. RESULTS: The iontophoresis has increased the percutaneous absorption of metopimazine and has decreased the lag time with 3.85+/-0.90 microg/(cm(2)h) and 1.9h for 0.5 mA/cm(2) and with 0.27+/-0.20 microg/(cm(2)h) and >8h for passive diffusion. Transdermal transport has been increased with current density and with isopropyl myristate and was not modified by ethanol or propylene glycol. CONCLUSION: Results indicated that iontophoresis is an effective method for transdermal administration of metopimazine.

Ethical observations on the choice of parenteral solvents. Choice of parenteral solvent....

The parenteral administration of insoluble drugs leads to the use of biologically active solvents inducing effects associated with ethical cause of concern including pain and pharmacological interactions. Selected vehicles currently used were ethically and scientifically reviewed. Our investigations allowed reinforcing the formulation decision tree with an ethical point of view. The last generation of cyclodextrin appears to be the safest solvent. Second choice could be lipidic emulsions, third choice being co-solvents, and finally non-ionic surfactants because of their hypersensitivity reactions. Screening tests including pH, osmolality measurements, cytotoxicity, and hemotoxicity, should allow to check the formulation tolerance before the animals' administration.

Enhanced Dissolution and Oral Bioavailability of Cyclosporine A: Microspheres Based on αß-Cyclodextrins Polymers.

Cyclosporine (CsA) has a selective property of suppressing various T-lymphocyte functions. This is of utmost importance in preventing allograft rejection by several organ transplantations, as well as in the treatment of systemic and local autoimmune disorders. However, the poor water solubility of CsA can be a major hurdle for its absorption into the blood stream, which leads to low bioavailability and thus less efficacy. The aim of this study was to prepare, characterize, and evaluate in vitro as well as in vivo, the potential of the innovative CsA drug delivery system. The latter contains CsA in spherical amorphous solid dispersion (SASD) which is embedded in an original α-cyclodextrin and ß-cyclodextrin polymer mixture (Poly-αß-CD) as a multifunctional amorphous carrier. The new developed SASD formulation showed that CsA was molecularly dispersed in αß-cyclodextrins in an amorphous form, as was confirmed by physicochemical characterization studies. Interestingly, the peptide secondary structure, and thus, the drug activity was not impacted by the preparation of SASD as was shown by circular dichroism. Furthermore, the in vitro CsA release profile kinetics was almost identical to the commercially available product Neoral®. This study presents the first in vivo proof-of-concept for a novel drug delivery system based on Poly-αß-CD containing CsA, with SASD allowing for increased bioavailibility. The pharmacokinetic parameters of cyclosporine A from the spherical spray-dried dispersion formulation was demonstrated in a "rat" animal model. For comparison, the commercially available Neoral® was studied. Importantly, the pharmacokinetic parameters were improved by extending Tmax from 2 to 3 h after the oral administration in rats, and eventually preventing the enterohepatic circulation. All these results clearly demonstrate the improved pharmacokinetic parameters and enhanced bioavailability of CsA in the new developed drug delivery system. These data demonstrated the superiority of the newly developed Poly-αß-CD formulation for oral administration of the poorly soluble CsA in vivo without altering its secondary structure. Poly-αß-CD can be a very useful tool for the oral administration of poorly water-soluble drugs.

Preparation and Characterization of Spherical Amorphous Solid Dispersion with Amphotericin B.

In the present study, new polymer microspheres of amphotericin B (AmB) were prepared by a spray drying technique using cyclodextrin polymers (Poly-CD) to improve the solubility and dissolution of AmB, to prevent in vivo toxic AmB aggregations. Formulations were characterized through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermal analysis, Raman spectroscopy, particle size, drug purity test and in vitro release studies. The analysis indicated that the chemical structure of AmB remained unchanged in the amorphous solid dispersion, but the structure was changed from crystalline to amorphous. AmB was completely release from such optimized formulations in dissolution media in 40 min. This work may contribute to a new generation of spherical amorphous solid dispersion using a cyclodextrin polymer, which has implications for the possibility of drug development for oral utilization or as powder aerosols for pulmonary administration.

Optimization of entrapment of metronidazole in amphiphilic beta-cyclodextrin nanospheres.

Several aspects of the manufacture of nanospheres containing metronidazole were studied. Nanospheres made of amphiphilic beta-cyclodextrin containing metronidazole were prepared by adding an acetone solution of amphiphilic cyclodextrin to an aqueous solution of metronidazole with or without Pluronic PE/F68 as the surfactant. An optimized formulation with high encapsulation efficiencies and with an appropriate particle size for intravenous administration, was developed. The entrapment of metronidazole was strongly dependent of the method of preparation and drug concentrations. These nanospheres prepared by nanocrystallization are promising carriers for metronidazole in the treatment of hepatic abscess.

Solid Dispersions for Oral Administration: An Overview of the Methods for their Preparation.

Oral drug delivery remains the most physiological and therefore the most preferred, simplest and easiest administration route. Nevertheless, a multitude of potentially clinically important drugs will not reach the market or achieve their full potential unless their oral bioavailability is improved by formulation. The aim of this review is to present an overview of properties, formulation, excipients and characterization of solid dispersions corresponding to one of the different formulation strategies for design and development of poorly soluble drugs. This work will review and compare in detail the evolution of solid dispersions focused on the different methods of formulation and production of solid dispersions, their stability, their release properties, their pharmacokinetics and methods for their physicochemical characterization.

Interaction Study of an Amorphous Solid Dispersion of Cyclosporin A in Poly-Alpha-Cyclodextrin with Model Membranes by (1)H-, (2)H-, (31)P-NMR and Electron Spin Resonance.

The properties of an amorphous solid dispersion of cyclosporine A (ASD) prepared with the copolymer alpha cyclodextrin (POLYA) and cyclosporine A (CYSP) were investigated by (1)H-NMR in solution and its membrane interactions were studied by (1)H-NMR in small unilamellar vesicles and by (31)P (2)H NMR in phospholipidic dispersions of DMPC (dimyristoylphosphatidylcholine) in comparison with those of POLYA and CYSP alone. (1)H-NMR chemical shift variations showed that CYSP really interacts with POLYA, with possible adduct formation, dispersion in the solid matrix of the POLYA, and also complex formation. A coarse approach to the latter mechanism was tested using the continuous variations method, indicating an apparent 1 : 1 stoichiometry. Calculations gave an apparent association constant of log Ka = 4.5. A study of the interactions with phospholipidic dispersions of DMPC showed that only limited interactions occurred at the polar head group level ((31)P). Conversely, by comparison with the expected chain rigidification induced by CYSP, POLYA induced an increase in the fluidity of the layer while ASD formation led to these effects almost being overcome at 298 K. At higher temperature, while the effect of CYSP seems to vanish, a resulting global increase in chain fluidity was found in the presence of ASD.

Solubility and dissolution rate of progesterone-cyclodextrin-polymer systems.

This contribution focused on the solubility improvement of the poorly water-soluble steroid hormone progesterone which, in its natural state, presents a reduced oral bioavailability. In the first part of this study, two simple, reproducible methods that were candidates for use in the preparation of inclusion complexes with cyclodextrins were investigated. Solubility capacities of the progesterone complex with hydroxypropyl-beta-CD (HPbeta-CD), hydoxypropyl-gamma-CD (HPgamma-CD), permethyl-beta-CD (PMbeta-CD), and sulfobutylether-beta-CD (SBEbeta-CD), prepared by the freeze-drying and precipitation methods, were evaluated by Higuchi phase solubility studies. The results showed that HPbeta-CD and PMbeta-CD were the most efficient among the four cyclodextrins for the solubilization of progesterone, with the highest apparent stability constants. Therefore, dissolution studies were conducted on these latest progesterone/cyclodextrin complexes and physical mixtures. Two additional natural cyclodextrins, beta-CD and gamma-CD, were taken as references. Hence, the influence of more highly soluble derivatives of beta-CD (HPbeta-CD, PMbeta-CD) on the progesterone dissolution rate, in comparison to pristine beta-CD, alongside an increase in the cavity width for gamma-CD versus beta-CD, were investigated. The dissolution kinetics of progesterone dissolved from HPbeta-CD, PMbeta-CD, and gamma-CD revealed higher constant rates in comparison to beta-CD. Therefore, the aim of the second part of this study was to investigate the possibility of improving the dissolution rate of progesterone/beta-CD binary systems upon formation of ternary complexes with the hydrophilic polymer, PEG 6000, as beta-CD had the smallest progesterone solubility and dissolution capacity among the four cyclodextrins studied (beta-CD, HPbeta-CD, HPgamma-CD and PMbeta-CD). The results indicated that dissolution constant rates were considerably enhanced for the 5% and 10% progesterone/beta-CD complexes in PEG 6000. The interaction of progesterone with the cyclodextrins of interest on the form of the binary physical mixtures, complexes, or ternary complexes were investigated by differential scanning calorimetry (DSC) and Fourier transformed-infrared spectroscopy (FT-IR). The results proved that progesterone was diffused into the cyclodextrin cavity, replacing the water molecules and, in case of ternary systems, that the progesterone beta-cyclodextrin was well dispersed into PEG, thus improving progesterone bioavailability for subsequent oral delivery in the same way as derivatized cyclodextrins. The present work proves that ternary complexes are promising systems for drug encapsulation.