Sci. Pharm., Volume 70, Issue 3 (September 2002) – 8 articles , Pages 233-316

Solid dispersions of ofloxacin (OFX) and of a number of carriers including chitosan and the water soluble polymers polyethylene glycol (PEG) 4000, PEG 20000, and polyvinylpyrrolidone K- 90 were prepared by solvent evaporation method in order to increase the dissolution of the drug. The solid dispersions were subjected to X-ray diffraction, DSC, and dissolution to characterize their physicochemical and dissolution properties. The results demonstrated a decrease in drug crystallinity at higher amounts of carrier. Dissolution studies indicated that the dissolution rate of OFX was markedly increased in these solid dispersion systems compared with the pure drug. The results also showed that the increase in dissolution rate was higher when the weight fraction of carriers increased. An influence of molecular weight of PEG on OFX dissolution could also be observed. In solid dispersion with 1:9 ratio drug to carrier, PEG 4000 gave highest drug dissolution rate, whereas in 1:1 ratio, chitosan seems to be the best carrier for drug release. It was concluded that chitosan might be the carrier of choice for dissolution enhancement in solid dispersions with high content of drug. Full article

In order to check the antibacterial potential of bischalcones derived from 4,6-diacetyl resorcinol, a number of chalcone derivatives were synthesized by condensation with appropriate aromatic aldehydes. Out of these compounds 3b-i, 4a and 4b showed a good antibacterial activity. Methylation of the two chelated hydroxyls reduced the activity. However, oxidative cyclization of 3a and 3b resulted in compounds 4a and 4b which were found to be considerably active. The alternative method of synthesis of 4a and 4b via Baker-Venkatararnan rearrangement did not succeed. Full article

Various amide-based prodrugs of sulphonamides have been synthesised by condensing appropriate sulphonamide moiety with different β-aroyl propionic acids. All the compounds have been evaluated for their antimicrobial and anti-inflammatory activities. Their structures were established on the basis of elemental analysis, ¹H NMR and Mass spectral data. Some of these compounds were found to have significant activity Full article

Simple and sensitive spectropliotometric methods are described for the assay of three piperazine derivatives ketoconazole, trimetazidine hydrochloride and piribedil based on cliarge-transfer and ion-pair complexation reactions. The first method is based on the reaction of the basic drug with iodine as o-acceptor in dry 1,2-dichloroethane to form a yellow colour due to the formation of charge-transfer complex showing maximum absorbence at 363, 364 and 359 nm for ketoconazole, trimetazidine hydrochlorid and piribedil, respectively. The second method is based on the reaction of basic drug with bromocresol green (BCG) in dry 1,2- dichloroethane to form a stable yellow coloured complex with maximum absorbance at 407, 408 and 410 nm for ketoconazol, trimetazidine hydrochloride and piribedil, respectively. Beer's law was obeyed for both methods and the relative standard deviations were found to be less than 1%. The two methods can be applied for the analysis of tablets and cream, with no evidence of interference from excipients. A more detailed investigation of the complex was made with respect to its composition association constant and free energy cliange. Full article

Leukotrienes (LTs) producing capacity was investigated in calcium ionophore A23 187- stimulated rabbit. rat and mice peripheral white blood cells suspension. A reverse phase high performance liquid chromatography technique and computerized UV spectroscopy were employed to isolate and quantitate the released LTs namely. LTC₄ and LTB₄. Preincubation of rabbit white blood cells at 37°C for 5 min followed by calcium ionophore-A23 187 (1 pM) stimulation for another 5 min produced an equal amounts of LTC₄ as compared to LTC₄ produced by human white blood cells (105±11 versus 95±9.5 pmol/10⁷ cells respectively; mean ±SEM). In contrast rabbit white blood cells synthesized significantly lower LTB₄ in comparison with LTB₄ produced by peripheral white blood cells from healthy control (168±18 versus 228±19 pmol/10⁷ cells respectively: mean ±SEM). When rat and mice white blood cells suspension were stimulated with calcium ionophore A23187 (1 µM) after preincubation at 37°C for 5 min, equivalent amounts of LTC₄ and LTB₄ were observed. However, LTB₄ and LTC₄ produced by rat and mice white blood cells were significantly lower in comparison with LTB4 and LTCj produced by human white blood cells stimulated with calcium ionophore-A23 187. These results demonstrate that rabbit. rat and mice white blood cells suspension possess the capacity to produce LTC₄ and LTB₄ from endogenous substrate after calcium ionophore-A23 187 stimulation. Full article