Formulation and evaluation of diclofenac controlled release matrix tablets made of HPMC and Poloxamer 188 polymer: an assessment on mechanism of drug release

In this study, hydrophilic hydroxypropyl methylcellulose matrices with various concentrations of Poloxamer 188 were used in the development of oral controlled release tablets containing diclofenac sodium. Four formulations of hydrophilic matrix tablets containing 16.7% w/w HPMC and 0, 6.7, 16.7 and 25.0% w/w Poloxamer 188, respectively, were developed. Tablets were prepared by direct compression and characterized for diameter, hardness, thickness, weight and uniformity of content. The influence of various blends of hydroxypropyl methylcellulose and Poloxamer 188 on the in vitro dissolution profile and mechanism of drug release of was investigated. In the four formulations, the rate of drug release decreased with increasing the concentration of Poloxamer 188 at the initial dissolution stages due to the increase in the apparent viscosity of the gel diffusion layer. However, in the late dissolution stages, the rate of drug release increased with increasing Poloxamer 188 concentration due to the increase in wettability and dissolution of the matrix. The kinetic of drug release from the tablets followed non-Fickian mechanism, as predicted by Korsmeyer-Peppas model, which involves diffusion through the gel layer and erosion of the matrix system

Lead enhances neutrophil apoptosis in albino rats

The present work was conducted to study the effect of lead, after in vivo and in vitro exposure, on neutrophil apoptosis in albino rats. For the in vivo study, adult female albino rats, with body weight range of 150-250 g, were randomized into test and control groups, 20 rats/group. Test groups were treated with lead acetate solution in distilled water by intraperitoneal injection at two dose levels [20 mg/kg body weight or 40 mg/kg body weight for either 4 weeks or 12 weeks for each dose level]. Control groups were treated with distilled water by intraperitoneal injection for either 4 weeks or 12 weeks. For the in vitro study, neutrophil cultures were prepared from 20 rats and each test culture was divided into two subdivisions and incubated for 24 hours with lead acetate at 2 concentrations, 20 or 40 mmol/ml cell culture. Control cultures were prepared from other 20 rats. Apoptosis was assessed morphologically by light microscope using Giemsa stain, fluorescence microscope using acridine orange stain and by assessment of DNA fragmentation by agarose gel electrophoresis

Lead modulates T lymphocyte functions in albino rats

The present work was performed to study the effects of subchronic and chronic in vivo exposure to lead on some parameters of T lymphocyte functions; namely, interferon-gamma [IFN-gamma] production and mitogen blastogenesis in albino rats. Adult female albino rats, with body weight range of 150-250 g, were randomized into test and control groups, 20 rats/group. Test groups were treated with lead acetate solution in distilled water by intraperitoneal injection at two dose levels [20 mg/kg body weight or 40 mg/kg body weight for either 4 weeks or 12 weeks for each dose level]. Control groups were treated with distilled water by intraperitoneal injection for either 4 weeks or 12 weeks. The results showed that lead exerted immunomodulatory effects on the studied immune parameters. It decreased gamma-IFN serum levels and enhanced blastogen transformation of lymphocytes in a dose and time-dependent manner. These results showed that lead differently affects T cell subpopulations. Dysregulation of the immune function may be the end result