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Miniaturized shake-flask HPLC method for determination of distribution coefficient of drugs used in inflammatory bowel diseases

-plug aspiration/injection method combined with high-performance liquid chromatography-mass spectrometry, Anal. Chem. 79 (2007) 8312–8315; https://doi.org/10.1021/ac0709798 4. T. Yamashita, I. Nishimura, T. Nakamura and T. Fukami, A system for LogD screening of new drug candidates using a water-plug injection method and automated liquid handler, J. Lab. Autom. 14 (2009) 276–281; https://doi.org/10.1016/j.jala.2008.10.001 5. Y. W. Alelyunas, L. Pelosi-Kilby, P. Turcotte, M. B. Kary and R. C. Spreen, A high throughput dried DMSO LogD lipophilicity measurement

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TLC-densitometric analysis of allantoin in Symphytum officinale L. roots

, S. Taguchi and S. Iwagami, Simultaneous measurement of diazolidinyl urea, urea, and allantoin in cosmetic samples by hydrophilic interaction chromatography, J. Chromatogr. B 877 (2009) 1005 – 1010; https://doi.org/10.1016/j.jchromb.2009.02.032

Open access
Alkyl polyglucoside vs. ethoxylated surfactant-based microemulsions as vehicles for two poorly water-soluble drugs: physicochemical characterization and in vivo skin performance

and A.O. Barel, Skin color measurements: comparison between three instruments: the Chromameter®, the DermaSpectrometer® and the Mexameter®, Skin Res. Technol. 6 (2000) 230-238; https://doi.org/10.1034/j.1600-0846.2000.006004230.x 22. V. Rogiers, EEMCO guidance for the assessment of transepidermal water loss in cosmetic sciences, Skin Pharmacol. Appl. Skin Physiol. 14 (2001) 117-128; http://dx.doi.org/10.1159/000056341 23. L. D. Ryan and E. W. Kaler, Alkyl polyglucoside microemulsion phase behaviour, Colloids Surf. A. 176 (2001) 69

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Preparation and evaluation of chitosan based thermoreversible gels for intraperitoneal delivery of 5-fluorouracil (5-FU)

Abstract

Sterile thermoreversibly gelling systems based on chitosan- glycerol phosphate were developed for intraperitoneal delivery of the antineoplastic agent 5-FU. The formulation was evaluated for gelling characteristics and in vitro drug release. Drug free gels were evaluated for in vitro cytotoxicity in L-929 mouse fibroblast cells. Drug loaded gels were subjected to acute toxicity studies in Swiss albino mice via intraperitoneal route and efficacy studies via intratumoral injections in subcutaneous colon carcinoma bearing BALB/c mice. The formulations gelled reversibly in 8 min at 37 °C and provided prolonged release of the drug. Drug free systems showed dose dependent cytotoxicity in fibroblast cells, while in vivo studies revealed a 2.8-fold increase in LD50 of 5-FU administered intraperitoneally as the developed system. Tumor volume measurements showed comparable efficacy of 5-FU administered as gel and commercial injection with a greatly improved safety profile of the former as adjudged from mortality and body weight measurements.

Open access
Comparison of classic and derivative UV spectrophotometric methods for determination of dextromethorphani hydrobromidum

Comparison of classic and derivative UV spectrophotometric methods for determination of dextromethorphani hydrobromidum

A method for the fast determination of dextromethorphani hydrobromidum in pharmaceutical preparations by classic spectrophotometry - zero and first-, second- and third-order derivative spectrophotometry, using "peak - peak" (P - P) and "peak - zero" (P - O) measurements has been performed. The calibration curves are linear within the concentration range of 1.0 - 25.0 μg ml-1 for dextromethorphani hydrobromidum. The procedure is simple, rapid and the results are reliable.

Open access
Analysis of Active Components in Salvia Miltiorrhiza Injection Based on Vascular Endothelial Cell Protection

Abstract

Correlation analysis based on chromatograms and pharmacological activities is essential for understanding the effective components in complex herbal medicines. In this report, HPLC and measurement of antioxidant properties were used to describe the active ingredients of Salvia miltiorrhiza injection (SMI). HPLC results showed that tanshinol, protocatechuic aldehyde, rosmarinic acid, salvianolic acid B, protocatechuic acid and their metabolites in rat serum may contribute to the efficacy of SMI. Assessment of antioxidant properties indicated that differences in the composition of serum powder of SMI caused differences in vascular endothelial cell protection. When bivariate correlation was carried out it was found that salvianolic acid B, tanshinol and protocatechuic aldehyde were active components of SMI because they were correlated to antioxidant properties.

Open access
Comparative bioavailability of two oral formulations of clopidogrel: Determination of clopidogrel and its carboxylic acid metabolite (SR26334) under fasting and fed conditions in healthy subjects

Abstract

Two randomized, single dose, 2-period, 2-sequence crossover studies were conducted to evaluate the comparative bioavailability of two clopidogrel formulations under fasting and fed conditions. Assessment of bioequivalence was based upon measurement of plasma concentrations of the parent drug, clopidogrel, and its major (inactive) metabolite, clopidogrel carboxylic acid, using improved methanol-free extraction. Bioequivalence of Krka’s formulation to the innovator’s formulation was demonstrated under both fasting and fed conditions on 205 volunteers. Confidence intervals for AUC0-t, AUC0-inf and Cmax of clopidogrel and its main metabolite were well within the acceptance range of 80.00 to 125.00 %. Food substantially increased the bioavailability of clopidogrel from both formulations, while no effect of food on the extent and rate of exposure to the metabolite was observed. The effect of food was comparable between the two formulations, as indicated by the same direction and rank of food impact on the bioavailability of both formulations.

Open access
Some variables affecting the characteristics of Eudragit E-sodium alginate polyelectrolyte complex as a tablet matrix for diltiazem hydrochloride

Abstract

Eudragit E (EE)-sodium alginate (SA) polyelectrolyte complexes (PECs) were prepared at pH 4 and 5.8 using sodium alginate of high (SAH) and low viscosity (SAL). The optimum EE-SA complexation mass ratio was determined using viscosity measurements. Interactions between EE and SA in PECs were characterized by Fourier transform infra-red spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Diltiazem hydrochloride (DTZ HCl) tablets were prepared using the prepared EE-SA PECs and their physical mixtures at different ratios as matrices. Tablets were evaluated for swelling characteristics and in vitro drug release. Tablets containing EE-SAH physical mixtures of ratios (1.5:1 and 1:3) as matrices were effective in achieving sustained release of DTZ HCl, where the percent drug released was significantly (p < 0.05) decreased compared to that from tablets either containing the same ratios of EE-SAL physical mixtures or the preformed EE- -SAH and EE-SAL PECs.

Open access
Rosuvastatin, Sildenafil and Their Combination in Monocrotaline-Induced Pulmonary Hypertension in Rat

Abstract

There is considerable interest in the pleiotropic effects of statins and their potential role in the treatment of pulmonary hypertension. Previous experimental findings indicate that a combination of lipophilic statins with phosphodiesterase type-5 inhibitor, sildenafil, can offer preventive effects on rat monocrotaline-induced pulmonary hypertension. The present study is aimed to assess whether therapeutic regimen provides any benefits. Seven days after pulmonary hypertension induction, hydrophilic rosuvastatin and sildenafil were given for 14 days to male Wistar outbred rats. Right ventricular pressure, right ventricle mass and three biomarkers were evaluated after 21 days: brain natriuretic peptide, high-density lipoprotein cholesterol and vascular endothelial growth factor. The present study demonstrates that administration of hydrophilic statin with sildenafil results in reduction of pulmonary vascular remodeling and right ventricular pressure. The results of biochemical measurements may suggest that statins play a positive role in right ventricle function or the process of angiogenesis in pulmonary hypertension development.

Open access
Spectrofluorimetric determination of gemifloxacin mesylate and linezolid in pharmaceutical formulations: Application of quinone-based fluorophores and enhanced native fluorescence

Abstract

Quinone-based fluorophores and enhanced native fluorescence techniques were applied for a fast quantitative analysis of gemifloxacin mesylate (GEM) and linezolid (LIN) in pharmaceutical formulations. For this purpose, three sensitive, accurate and precise spectrofluorimetric methods were developed. GEM, as an n-electron donor, reacts with 7,7,8,8-tetracyanoquinodimethane (method A) and 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (method B) as п-electron acceptors, forming charge transfer complexes that exhibit high fluorescence intensity at 441 and 390 nm upon excitation at 260 and 339 nm, respectively. Method C depends on measurement of enhanced native fluorescence of LIN in phosphate buffer (pH 5) at 380 nm upon excitation at 260 nm. Experimental factors affecting fluorescence intensity were optimized. Linearity was obtained over concentration ranges 50-500, 10-60 and 20-400 ng mL-1 for methods A, B and C, respectively. The developed methods were validated and successfully applied for determination of the cited drugs in tablets.

Open access