Formulation and bioavailability of controlled release salbutamol sulphate tablets using natural additives.

Salbutamol sulphate granules and physical mixtures were prepared using mastic with various natural additives. The prepared granules and physical mixtures were examined using IR and DSC. The obtained results indicate that there is no interaction between salbutamol sulphate and the formulation ingredients used. The physical properties and release behavior of the formulated tablets prepared from granules and physical mixtures were evaluated and showed good physical properties. The rate of drug release from tablets prepared from granules was found to be lower than that prepared from physical mixtures at fixed mastic concentration and the same additive. The rate of drug release decreased with increased mastic concentration in formulated tablets. Pectin and sodium alginate allowed the best controlled release rate of the drug. On the basis of the results obtained from the controlled release studies, selected sulbutamol formulations were subjected to an in vivo comparison with commercial sulbutamol tablets. The pharmacokinetic parameters AUC(0-24), C(max), and T(max) of sulbutamol from the selected formulation were determined after administration of a single oral dose of 8 mg and compared statistically using an ANOVA test. There was no significant difference in the AUC(0-24). On the other hand, there was a significant difference in the C(max) and T(max) between the commercial and the formulated tablets. These results demonstrate that the formulated tablets extended the time of the drug effect.

Stability, bioavailability, and ulcerative activity of diclofenac sodium-mastic controlled release tablets.

Controlled release tablets containing 50 mg diclofenac sodium (DS) and 40% mastic with other natural additives were prepared. Drug release was examined and stability was studied using non-isothermal and isothermal thermogravimetric analysis (TGA). The bioavailability of two controlled release tablet formulations was studied and compared to that of commercial tablets, and rabbit stomachs were also histologically examined 24 h after administration of the various tablets. Additives of pectin and sodium alginate indicated the controlled release profile of the drug. Non-isothermal TG revealed two stages of thermal decomposition for all formulations. Isothermal TG revealed that degradation of the drug in the tablet formulations follows first-order kinetics. The obtained degradation rate constants at various temperatures were plotted according to the Arrhenius equation. The degradation rate constant at 25°C was determined and used in estimation of shelf life. The obtained shelf lives of all formulations ranged from 3.38-4.92 years. In comparative studies with commercial tablets, the bioavailability of the drug from the two formulated tablets had no statistically significant difference in terms of the AUC and produced prolonged blood levels of DS with a delayed peak. The two controlled release tablet formulations resulted in no histological alterations in the stomach in terms of mucous surface cells and glands; in comparison, commercial tablets resulted in a disrupted mucous layer, necrotic ulcerations, hemorrhaging, and inflammatory cell infiltration along the base of the gastric glands.

Effect of surfactant incorporation techniques on sulphamethoxazole suppository formulations.

In vitro release, stability as well as bioavailability of sulphamethoxazole (SMZ) suppositories were investigated using solid dispersion techniques for surfactant incorporation. Tween 20, Tween 80 and Myrj 53 were the surfactants utilized in this investigation. Suppositories were prepared by fusion method using Witepsol H15 as a base. It was found that SMZ-surfactant physical mixture showed the highest drug release from suppositories. This indicated that the technique of surfactant incorporation has a great role in enhancing the drug release from suppositories. Stability study revealed that the technique of surfactant incorporation did not affect the drug stability. Bioavailability investigation has proved surfactant incorporation in suppository formulations of SMZ in fatty bases.