Sci. Pharm., Volume 73, Issue 1 (March 2005) – 5 articles , Pages 1-74

Sustained release matrix tablets of clarithromycin were prepared using different polymers as Hydroxypropyl methylcellulose (H PMC), Carbopol 934 and Eudragit RL/PO by direct compression technique. For the quality control of these formulations, weight deviation, hardness, friability, diameter-height ratio, content uniformity of the active substance and in vitro dissolution technique were performed. HPLC was used for the assay of clarithromycin and the assay method was validated. Dissolution profiles of the tablets were plotted and evaluated kinetically. The effects on drug release of polymer type and concentrations were investigated by 2³ factorial design. The tablets containing HPMC, Carbopol 934 and Eudragit RLIPO were found suitably to sustain drug release Full article

Det-Morph is a new approach for a detailed morphological analysis of primary segments of leafs and ray florets from some species of the Achillea millefolium group (Asteraceae). 56 features of primary segments and 21 features of ray florets both in two different transformation types are yielded by the new software. The usefulness of these features is shown on data of 616 specimens of Achillea setacea, A. collina, A.ceretanica, Adistans s.l., A. millefolium s.l. and A.pannonica. Full article

The oxygenated monoterpenes 1,8-cineole, α-terpineol, terpinen-4-ol and camphor as well as essential oils of pine, rosemary and tea tree, rich in these volatiles, were tested for their antimicrobial activities against some different strains of yeast, Gram-(-)- and Gram-(+)-bacteria by agar diffusion and agar dilution method, respectively. The same was done using the phenolic aroma compound eugenol as a reference-substance. The monoterpene alcohols a-terpineol and terpinen-4-ol were found to be active against all strains used in a wide range. The same result was obtained for the testings of essential oils of pine, rosemary (2 samples) and tea tree. Nearly all aroma chemicals and essential oils did show a significant high antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. For qualitative and quantitaive investigations of the key aroma compounds and the compositions of the essential oils, gas chromatographic methods (GC-FID and GCMS with columns of different polarities) were used and the results correlated with that of the antimicrobial testings. The obtained data are discussed to get more insight into the influence of pure aroma compounds on antimicrobial activities of essential oils. Full article

The critical micelle concentrations (c.m.c.) of alkyloxy homologs of local anesthetic N-[2-(2-alkyloxyphenylcarbamolyoxy)-ethyl]-piperidinium chloride (CnA) with n=3, 5, 7, 8, 10 and 12 carbons in alkyloxy substituent determined by surfactant ion sensitive electrode (ISE) depend exponentially on n: lnc.m.c.=0.70+0.49n and lnc.m.c.=0.57+0.62n at t=25 °C and pH≈4.5 in water and 0.1 mol.l-1 NaCl solution, respectively, where the free energy of transfer of the alkyloxymethylene group from the aqueous phase into the micelle hydrophobic interior is ΔG0=(-0.49±0.008)RT in water and ΔG0=(-The critical micelle concentrations (c.m.c.) of alkyloxy homologs of local anesthetic N-[2-(2-alkyloxyphenylcarbamolyoxy)-ethyl]-piperidinium chloride (CnA) with n=3, 5, 7, 8, 10 and 12 carbons in alkyloxy substituent determined by surfactant ion sensitive electrode (ISE) depend exponentially on n: lnc.m.c.=0.70+0.49n and lnc.m.c.=0.57+0.62n at t=25 °C and pH≈4.5 in water and 0.1 mol.l^-1 NaCl solution, respectively, where the free energy of transfer of the alkyloxymethylene group from the aqueous phase into the micelle hydrophobic interior is ΔG⁰=(-0.49±0.008)RT in water and ΔG⁰=(-0.62±0.06)RT in the 0.1 mol.l^-1 NaCl solution. The enthalpic and entropic contributions to the standard Gibbs energy of micellization of heptacainium chloride (heptyloxy homologs of C_nA) in 0.1 mol.l^-1 NaCl solution were calculated according to the phase separation model in the temperature range of 25-45 °C.0.62±0.06)RT in the 0.1 mol.l-1 NaCl solution. The enthalpic and entropic contributions to the standard Gibbs energy of micellization of heptacainium chloride (heptyloxy homologs of CnA) in 0.1 mol.l-1 NaCl solution were calculated according to the phase separation model in the temperature range of 25-45 °C. Full article

A simple titrimetric method is described for the determination of dothiepin hydrochloride. The method is based on titrating the cited drug with potassium salts of trioxalato-ferrate (III) (TOXFe), trioxalato-chromate (III) (TOXCr), trioxalatoaluminate (III) (TOXAI) and trioxalato-cobaltate (III) (TOXCo). The end point was located conductimetrically. The effect of solvent, molar ratio, reagent concentration and temperature were studied. Based on conductimetric measurements at 25 °C, the solubility, solubility product, free energy (ΔG) and entropy changes (ΔS) of the ion associates were calculated. Calculations of the enthalpy change (ΔH) are based on atomic absorption measurements of the solubility of the ion associates at different temperatures. The method allowed the determination of 6.63-29.87, 3.31-49.78, 9.95-49.78 and 3.31-33.19 mg of the studied drug using TOXFe, TOXCr, TOXAl and TOXCo, respectively. The method was further applied successfully to some dosage forms containing the cited drug, and the obtained results were compared favorably with those previously given by the official method. Full article