Development of Vaginal Carriers Based on Chitosan-Grafted-PNIPAAm for Progesterone Administration.

Chitosan-based hydrogels possess numerous advantages, such as biocompatibility and non-toxicity, and it is considered a proper material to be used in biomedical and pharmaceutical applications. Vaginal administration of progesterone represents a viable alternative for maintaining pregnancy and reducing the risk of miscarriage and in supporting the corpus luteum during fertilization cycles. This study aimed to develop new formulations for vaginal administration of progesterone (PGT). A previously synthesized responsive chitosan-grafted-poly (N-isopropylacrylamide) (CS-g-PNIPAAm) was formulated in various compositions with polyvinyl alcohol (PVA) as external crosslinking agent to obtain pH- and temperature-dependent hydrogels; the hydrogels had the capacity to withstand shear forces encountered in the vagina due to its mechanism of swelling once in contact with vaginal fluids. Three different hydrogels based on grafted chitosan were analyzed via Fourier-transform infrared spectroscopy (FTIR), swelling tests, in vitro drug release, and bioadhesion properties by TA.XTplus texture analysis. A higher amount of PVA decreased the swelling and the bioadhesion capacities of the hydrogel. All hydrogels showed sensitivity to temperature and pH in terms of swelling and in vitro delivery characteristics. By loading progesterone, the studied hydrogels seemed to possess even higher sensitivity than drug-free matrices. The release profile of the active substance and the bioadhesion characteristics recommended the CS-g-PNIPAAm/PVA 80/20 +PGT (P1) hydrogel as a proper constituent for the vaginal formulation for progesterone administration.

Design, Synthesis, In Silico and In Vitro Studies for New Nitric Oxide-Releasing Indomethacin Derivatives with 1,3,4-oxadiazole-2-thiol Scaffold.

Starting from indomethacin (IND), one of the most prescribed non-steroidal anti-inflammatory drugs (NSAIDs), new nitric oxide-releasing indomethacin derivatives with 1,3,4-oxadiazole-2-thiol scaffold (NO-IND-OXDs, 8a-p) have been developed as a safer and more efficient multitarget therapeutic strategy. The successful synthesis of designed compounds (intermediaries and finals) was proved by complete spectroscopic analyses. In order to study the in silico interaction of NO-IND-OXDs with cyclooxygenase isoenzymes, a molecular docking study, using AutoDock 4.2.6 software, was performed. Moreover, their biological characterization, based on in vitro assays, in terms of thermal denaturation of serum proteins, antioxidant effects and the NO releasing capacity, was also performed. Based on docking results, 8k, 8l and 8m proved to be the best interaction for the COX-2 (cyclooxygense-2) target site, with an improved docking score compared with celecoxib. Referring to the thermal denaturation of serum proteins and antioxidant effects, all the tested compounds were more active than IND and aspirin, used as references. In addition, the compounds 8c, 8h, 8i, 8m, 8n and 8o showed increased capacity to release NO, which means they are safer in terms of gastrointestinal side effects.

New nitric oxide-releasing indomethacin derivatives with 1,3-thiazolidine-4-one scaffold: Design, synthesis, in silico and in vitro studies.

In this study we present design and synthesis of nineteen new nitric oxide-releasing indomethacin derivatives with 1,3-thiazolidine-4-one scaffold (NO-IND-TZDs) (6a-s), as a new safer and efficient multi-targets strategy for inflammatory diseases. The chemical structure of all synthesized derivatives (intermediaries and finals) was proved by NMR and mass spectroscopic analysis. In order to study the selectivity of NO-IND-TZDs for COX isoenzymes (COX-1 and COX-2) a molecular docking study was performed using AutoDock 4.2.6 software. Based on docking results, COX-2 inhibitors were designed and 6o appears as the most selective derivative which showed an improved selective index compared with indomethacin (IND) and diclofenac (DCF), used as reference drugs. The biological evaluation of 6a-s, using in vitro assays has included the anti-inflammatory and antioxidant effects as well as the nitric oxide (NO) release. Referring to the anti-inflammatory effects, the most active compound was 6i, which was more active than IND and aspirin (ASP) in term of denaturation effect, on bovine serum albumin (BSA), as indirect assay to predict the anti-inflammatory effect. An appreciable anti-inflammatory effect, in reference with IND and ASP, was also showed by 6k, 6c, 6q, 6o, 6j, 6d. The antioxidant assay revealed the compound 6n as the most active, being 100 times more active than IND. The compound 6n showed also the most increase capacity to release NO, which means is safer in terms of gastro-intestinal side effects. The ADME-Tox study revealed also that the NO-IND-TZDs are generally proper for oral administration, having optimal physico-chemical and ADME properties. We can conclude that the compounds 6i and 6n are promising agents and could be included in further investigations to study in more detail their pharmaco-toxicological profile.

Chitosan-Graft-Poly(N-Isopropylacrylamide)/PVA Cryogels as Carriers for Mucosal Delivery of Voriconazole.

The objective of this study was to prepare and characterize physically crosslinked gel formulations of chitosan (CS)-graft-poly(N-isopropyl acrylamide) (PNIPAAm) and polyvinyl alcohol (PVA) for smart delivery of an antifungal drug, Voriconazole, for mucosal applications. For this purpose, cryogels of CS-g-PNIPAAm/PVA and CS/PVA were tested by means of texture profile analysis and rheology to determine optimal matrix properties for topical application. The ratio of 75/25 v/v % CS-g-PNIPAAm/PVA was selected to be used for formulation since it gave low compressibility and hardness (1.2 and 0.6 N) as well as high adhesion properties and non-Newtonian flow behavior. The cryogels and formulations were further characterized by means of FTIR spectroscopy, swelling behavior, texture analysis, scanning electron microscopy (SEM), thermal (differential scanning calorimetry (DSC) and TGA), and rheological behavior. The drug loading capacity and in vitro release profile of the drug, storage stability, and cytotoxicity tests were also performed for the gel formulation. The FTIR, DSC, and TGA results verified the successful formation of cryogels. Swelling studies revealed a pH-dependent swelling ability with a maximum swelling degree of 1200% in acid and 990% in phosphate buffer (pH 7.4). Thermal studies showed that CS-g-PNIPAAm/PVA 75/25 had higher thermal stability proving the structural complexity of the polymer. The loading capacity of Voriconazole was found to be 70% (w/w). The in vitro release profiles of Voriconazole showed Fickian release behavior for CS-g-PNIPAAm/PVA 75/25 gel with an approximate delivery of 38% within 8 h, slower than matrices containing unmodified chitosan. The storage stability test exhibited that the gel formulation was still stable even after aging for two months. Moreover, the cell culture assays revealed a non-toxic character of the polymeric matrix. Overall results showed that the CS-g-PNIPAAm/PVA 75/25 hydrogel has the potential to be used as a smart polymeric vehicle for topical applications.

Toxicity, Biocompatibility, pH-Responsiveness and Methotrexate Release from PVA/Hyaluronic Acid Cryogels for Psoriasis Therapy.

Poly(vinyl alcohol)/hyaluronic acid cryogels loaded with methotrexate were studied. The physical⁻chemical characterization of cryogels was performed by FT-IR spectroscopy, scanning electron microscopy, differential scanning calorimetry and dynamic mechanical thermal analysis. Acute toxicity and haematological parameters were determined by "in vivo" tests. The biocompatibility tests proved that the obtained cryogels showed significantly decreased toxicity and are biocompatible. The pH-responsiveness of the swelling behaviour and of the methotrexate release from the poly(vinyl alcohol)/hyaluronic acid (PVA/HA) cryogels were studied in a pH interval of 2⁻7.4. A significant change in properties was found at pH 5.5 specific for treatment of affected skin in psoriasis disease.

Fast RP-HPLC Method for the Determination of Bisoprolol.

Aim: To develop and validate a fast, robust, isocratic reversed-phase high performance liquid chromatographic method for the determination of bisoprolol in bulk and pharmaceutical formulations. Material and Method: Optimum separation of bisoprolol was achieved using as stationary phase a Zorbax SB-C18 column (100×3 mm; 5µm). The mobile phase was a mixture of phosphate buffer (pH = 3.5) and acetonitrile (70:30) with a flow rate of 1mL/min. The UV detection was performed at 225nm. The temperature of the column and autosampler was 25°C. The specificity was assessed by using metoprolol as internal standard. The method was validated in accordance with the current ICH guidelines in terms of linearity, limit of detection, limit of quantification, precision, accuracy, recovery and system suitability. Results: The retention time for bisoprolol was 1.158 minute. The calibration graph was linear in the concentration range 5-90 µg/mL. The LOD and LOQ of bisoprolol were 1.63 µg/mL and 4.94 µg/mL, respectively. The intra and interday precision of measurements were lower than the accepted criteria (RSD ≤ 2%). The recovery values of HPLC determination of bisoprolol from tablets proved that none of the excipients influenced the results of the analysis. Conclusions: The assay it was found to be accurate, reproducible, sensitive and less time consuming. The proposed method can be successfully applied to quality control studies of pharmaceutical products.

A NEW SPECTROPHOTOMETRIC METHOD FOR THE ASSAY OF LISINOPRIL.

AIM: A new spectrophotometric method for the assay of lisinopril using 2,4-dinitrophenol as reagent is described. MATERIAL AND METHODS: The method involved the addition of 2,4-dinitrophenol to lisinopril in methanol followed by absorbance measurement at 400 nm. Experimental conditions that provide wide linear range, maximum sensitivity, selectivity, accuracy and precisions were optimized. RESULTS AND DISCUSSIONS: Beer's law was obeyed in the concentration range 2.0-14.0 µg/mL. Linear regression equation of calibration graph was A = 0.005 + 0.045 x concentration, with a regression coefficient (r) of 0.9995 (n = 8). The limits of detection (LOD) and quantification (LOQ) calculated according to the ICH guidelines were 0.42 and 1.42 µg/mL, respectively. Accuracy and precision of the assays were determined by computing the intra-day and inter-day variations at three different lisinopril concentrations; the intra-day and inter-day RSD was < 1.43% and accuracy was better than 1.72%. CONCLUSIONS: The proposed method is simple, easy to perform, sensitive, linear, precise, accurate and robust.

ANTINFLAMMATORY ACTIVITY OF AN N, N'-DISALICYLIDENEMETHYLENDIAMINE-DERIVED SCHIFF BIS BASE AND ITS COPPER(II) COMPLEX.

AIM: The cooper(II) complex combination of N, N'-disalicylidenemethylenediamine and the Schiff bis base were investigated for anti-inflammatory activity. MATERIAL AND METHODS: In vivo, the anti-inflammatory activity of the metallic complex in comparison with the activity of the Schiff bis base was tested by the method of Winter and co-workers using the Levy technique. RESULTS AND DISCUSSIONS: Our study on the anti-inflammatory activity of a new Schiff bis base and its complex cooper(II) combination showed that the Schiff bis bases exhibited significant anti-inflammatory action in acute experimental inflammation when compared to the control group. The copper cation from the complex combination enhanced the anti-inflammatory effect of the Schiff bis base, the effect being stronger at doses of 10 mg/kg cooper(II) complex. CONCLUSIONS: The Schiff bis base and its cooper(II) complex had an anti-inflammatory effect comparable to that of indomethacin.

Effect of apitherapy products against carbon tetrachloride-induced toxicity in Wistar rats.

The present paper aimed to evaluate the influence of apitherapy diet in Wistar rats with carbon tetrachloride induced hepatotoxicity, by the means of biochemical determinations and histopathological changes of liver, spleen, pancreas and testicular tissue. The experiment was carried out on six groups of male Wistar rats. Hepatic lesions were induced by intraperitoneal injection of carbon tetrachloride (dissolved in paraffin oil, 10% solution), 2 mL per 100 g, every two days, for two weeks. Hepatoprotection was achieved with two-apitherapy diet formulations (containing honey, pollen, propolis, Apilarnil, with/without royal jelly), that have been administered for six up to nine weeks. The biochemical results revealed that the two-apitherapy diet formulations had a positive effect improving the enzymatic, lipid, and protein profiles, coagulation, mineral parameters and also the bilirubin levels, after six weeks of treatment. The histopathological results demonstrated the benefit of the two-apitherapy diet formulations on reducing the toxicity of liver, spleen and pancreas in laboratory animals, after six and nine weeks, respectively. In conclusion, apitherapy products have a hepatoprotective effect in carbon tetrachloride-induced hepatopathy.

Spectrophotometric method for estimation of bisoprolol fumarate in tablets.

UNLABELLED: Bisoprolol fumarate is prescribed for the treatment of hypertension and angina pectoris. AIM: The purpose of this study was to develop a simple, sensitive, accurate, and reproducible method for estimation of bisoprolol fumarate in tablets. MATERIAL AND METHODS: The proposed method was based on a yellow colored complex formed with tropaeolin 00, extractable in dichloromethane with maximum absorbance at 412 nm. The method was validated statistically. RESULTS: The linearity domain was observed in the concentration of 5-30 microg/ml. The recovery studies confirmed the accuracy of the proposed method. CONCLUSIONS: The proposed method can be applied for the routine analysis of bisoprolol from formulations.

Validation of a spectrophotometric assay method for bisoprolol using picric acid.

UNLABELLED: Bisoprolol is a drug belonging to beta blockers drugs used primarily for the treatment of cardiovascular diseases. AIM: A spectrophotometric method for quantitative determination of bisoprolol was developed based on the formation of a complex combination between bisoprolol and picric acid. MATERIAL AND METHODS: The complex combination of bisoprolol and picric acid has a maximum absorbance peak at 420 nm. Optimum working conditions were established and the method was validated. RESULTS: The method presented a good linearity in the concentration range 5-120 microg/ml (regression coefficient r2 = 0.9992). The RSD for the precision of the method was 1.74 and for the intermediate precision 1.43, and recovery values ranged between 98.25-101.48%. CONCLUSIONS: The proposed and validated spectrophotometric method for the determination of bisoprolol is simple and cost effective.

Spectrometric method for the assay of ramipril using molybdophosphoric acid.

UNLABELLED: Ramipril is a drug of the angiotensin converting enzyme inhibitor class. AIM: A new molecular absorbance spectrometric method was developed for the assay of ramipril using molybdophosphoric acid in acidic medium. MATERIAL AND METHODS: The reaction product showed a maximum absorbance at 361 nm. The optimum conditions of the reaction were established. The developed method was validated. RESULTS: The method showed a good linearity in the range of 8 - 36 microg/ml (correlation coefficient r = 0.9996). The detection limit (LD) was 0.86microg/ml and the quantification limit (LQ) 2.88 pg/ml. Precision and accuracy were determined (RSD = 1.15%); mean recovery was 98.90% in the 97.13-101.03% concentration range. CONCLUSIONS: The proposed method is simple, easy to perform, sensitive, linear, precise, accurate and robust.

Evaluation of some pharmaceutical formulations of lisinopril through dissolution testing.

AIM: Lisinopril is a drug of the angiotensin converting enzyme (ACE) inhibitor class that is primarily used in treatment of hypertension, congestive heart failure, heart attacks and also in preventing renal and retinal complications of diabetes. We compared the dissolution profiles of Lisinopril 20 mg tablets (Antibiotice S.A. lasi) and Zestril 20 mg tablets (Astra Zeneca). MATERIAL AND METHOD: Because lisinopril is a third class active substance, we performed dissolution tests in standard media at three pH values: 1.2, 4.5 and 6.8 using the paddle apparatus at 75 rpm. RESULTS: Both pharmaceutical formulations present a dissolution percentage more than 85% (Q) of the labeled amount. CONCLUSION: Both pharmaceutical formulations present similar dissolution profile. Key words:

[Construction and characterisation of a selective membrane electrode for the assay of lisinopril]. / Constructia si caracterizarea unui electrod membrana selectiv pentru determinarea lisinoprilului.

UNLABELLED: In order to analyze lisinopril using a selective membrane electrode, the electro-active compound was obtained and included in the selective membrane. The new analysis method was developed and validated. MATERIAL AND METHOD: The electro-active compound was obtained through the precipitation of lisinopril in acidic media using silicowolframic acid solution. The membrane was obtained by mixing the electro-active compound with polyvinylchloride using tetrahydrofurane as solvent. The solution was evaporated in order to obtain a thick membrane, which was then attached at one end of a polyvinylchloride tube. The internal Ag/AgCl reference electrode was inserted in that tube. The assembly was filled with a lisinopril internal solution. The electrode was characterized by establishing the following characteristics: electrode slope, selectivity, optimal pH range, response time and life-time period. The developed method was validated. RESULTS: The method showed a good linearity in the range of 10(-7) and 10(-2)M (the correlation coefficient r = 0.9991). The detection limit (LD) was 8,66 x 10(-8)M and the quantification limit (LQ) was 7,8 x 10(-7)M. There were established the precision (RSD = 1.73%) and the accuracy (mean recovery was 99.92%) CONCLUSIONS: The experimental results demonstrated a good sensibility.

A new liquid chromatography-tandem mass spectrometry method for determination of bisoprolol in human plasma samples.

Liquid chromatography (LC) coupled with mass spectrometry (MS) detection is one of the most powerful analytical tools for organic compound analysis. The advantages of using LC/MS methods over HPLC methods include: selectivity, chromatographic integrity, peak assignment, structural information, and rapid method development. In this paper, a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the determination of bisoprolol in human plasma samples, using metoprolol as internal standard and liquid-liquid extraction procedure. The assay has proven to be sensitive, specific and reproducible, suitable to determine the bisoprolol concentration, following a single oral administration of a 10 mg bisoprolol tablet in 22 healthy volunteers, in the bioequivalence study of Bisoprolol 10 mg coated tablets, produced by Antibiotice S.A. versus Concor 10 mg, produced by Merck.

[Analytical application of phosphotungstic acid complexes. Synthesis and characterisation]. / Complecsi ai acidului fosfowolframic cu aplicatii analitice. Sinteza si caracterizare.

UNLABELLED: Phosphotungstic acid forms salt type ionic association complexes with a large number of medicinal drugs that contain cation forming proton acceptor moieties. MATERIAL AND METHOD: Ranitidine, nizatidine and famotidine complexes with phosphotungstic acid were synthesized and subsequently characterized by their melting point, water solubility, specific absorbance, UV spectra and IR spectra. RESULTS: These sparingly soluble complexes were applied for the fabrication of membrane selective electrodes for quantitative potentiometric determination of ranitidine, nizatidine and famotidine. CONCLUSIONS: There have been synthesized phosphotungstic acid complexes with uses in fabrication of membrane selective electrodes for quantitative potentiometric determination of ranitidine, nizatidine and famotidine.

[Quantitative determination of adrenaline by visible spectrophotometric method]. / Determinarea spectrofotometrica în vizibil a adrenalinei.

UNLABELLED: A sensible and rapid spectrophotometric assay for adrenaline was developed. MATERIAL AND METHOD: The method is based on the reaction with ammonium molybdate and sodium nitrite in acid medium. RESULTS: The obtained compound is stable, soluble in water and has the absorbtion maximum at 405 nm. Beer's law is valid within a concentration range of 20-160 microg/mL. The validity of the method was tested by statistical analysis of the experimental data using the linearity, the scale's calibration factor, the detection limit, the quantification limit and the precision. CONCLUSIONS: A new method for the assay of adrenaline in pharmaceutical products has been developed.

[Turbidimetric assay of famotidine]. / Determinarea cantitativa turbidimetrica a famotidinei sub forma de fosfomolibdat.

This paper proposes a new method for the quantitative determination of famotidine, based on its reaction with phosphomolybdic acid. The measurements were carried out at wavelength of 400 nm. This method has been validated and it has been applied to the determination of famotidine in pharmaceutical products.

[UV spectrophotometric assay of famotidine in combination with picrolonic acid, picrolinate]. / Determinarea cantitativa spectrofotometrica in uv a famotidinei sub forma de picrolonat.

Famotidine, belonging to H2-antagonist group, is a compound containing a thiazolic moiety and it is used in peptic ulcer therapy. This paper debates the possibility of developing a new ultraviolet spectrophotometric assessment by using the reaction between famotidine and picrolonic acid. We carried out our determinations at 362 nm, where the absorbency of famotidine - picrolonic acid complex is maximal, and we have established the optimal reaction conditions. This method was successfully applied for famotidine assay from pharmaceutical dosage forms.

[Membrane-selective electrodes for drug analysis. Note II]. / Electrozi membrana-selectivi in analiza medicamentelor. Nota II.

Seven membrane-selective electrodes with PVC matrix and liquid-membrane for N-butylscopolamine with different electroactive materials are presented. These electrodes have a linear response in the concentration range of 10(-6) - 10(-2) M N-butylscopolamine bromide, with a detection limit between 4.58 x 10(-7)M and 1.09 x 10(-6)M. These electrodes were used with good results for quantitative assay by direct potentiometry and potentiometric titration of N-butylscopolamine bromide from pharmaceutical formulations. Recovery was between 95.50% and 99.20% for N-butylscopolamine bromide of injectable solutions.