ABSTRACT
The aim of the present study was to improve the solubility and dissolution rate of a poorly water-soluble drug by a solid dispersion technique, in order to investigate the effect of these polymers on release mechanism from solid dispersions. Diazepam was used as a model drug to evaluate its release characteristics from different matrices. Solid dispersions were prepared by using polyethylene glycol 6000 (PEG-6000), HPMC, HPC and Poloxamer in different drug-to-carrier ratios (1:2, 1:4, 1:6, 1:8, 1:10). The solid dispersions were prepared by solvent method. The pure drug and solid dispersions were characterized by in vitro dissolution study. Distilled water was used as dissolution media, 1000 ml of distilled water was used as dissolution medium in each dissolution basket at a temperature of 37°C and a paddle speed of 100 rpm. The very slow dissolution rate was observed for pure Diazepam and the dispersion of the drug in the polymers considerably enhanced the dissolution rate. This can be attributed to improved wettability and dispersibility, as well as decrease of the crystalline and increase of the amorphous fraction of the drug. SEM (Scan-ning Electron microscope) studies shows that the solid dispersion having a uniform dispersion. Solid dispersions prepared with PEG-6000, Poloxamer showed the highest improvement in wettability and dissolution rate of Diaze-pam. Solid dispersion containing polymer prepared with solvent method showed significant improvement in the release profile as compared to pure drug, Diazepam.
ABSTRACT
Aims: The crude ethanolic leaf extract of Bacopa monnieri (L) Penn. (family: Scrophulariaceae) was evaluated for its possible phytochemical nature (group determination of plant constituent) and selected pharmacological activities (analgesic, antidiarrhoeal and cytotoxic activity) growing in Bangladesh. Methodology: The antinociceptive activity was evaluated by acetic acid induced writhing model, antidiarrhoeal activity by castor oil induced diarrheal method and cytotoxicity by brine shrimp lethality bioassay. Results: Phytochemical analysis of the ethanolic extract of B. monnieri indicated the presence of reducing sugar, tannins, steroid, alkaloid, saponin and gum types of compounds. The ethanolic extract of B. monnieri has effect on acetic acid induced writhing in mice. At the dose of 250 mg/kg and 500 mg/kg of body weight, the extract produced 36.69% and 59.17% writhing inhibition in test animals respectively. The results were statistically significant (p <0.01 and p <0.001) and was comparable to the standard drug Diclofenac Na, which showed 72.78% at a dose of 25 mg/kg weight. The ethanolic extract of B. monnieri has effect on castor oil induced diarrhea in mice. The result showed that the extract decreased the mean number of defecation which were 35.42 % and 47.92 % (p <0.001) at the doses of 250mg/kg and 500mg/kg respectively. The latent period for the extract treated group was increased (p <0.01) as compared to control group. The ethanolic of extract of B. monnieri showed significant toxicity to the brine shrimp nauplii. The concentrations of crude extract for 50% mortality (LC50) and 90% mortality (LC90) were 40 μg/mL and 150 μg/mL respectively. Conclusion: Therefore, the obtained results tend to suggest the antinociceptive, antidiarrhoeal and cytotoxic activities of crude ethanolic extract of Bacopa monnieri leaves and thus provide the scientific basis for the traditional uses of this plant part as a remedy for pain and diarrhoea.
ABSTRACT
The aim of the present study was to improve the solubility and dissolution rate of a poorly water-soluble drug by a solid dispersion technique, in order to investigate the effect of these polymers on release mechanism from solid dispersions. Diazepam was used as a model drug to evaluate its release characteristics from different matrices. Solid dispersions were prepared by using polyethylene glycol 6000 (PEG-6000), HPMC, HPC and Poloxamer in different drug-to-carrier ratios (1:2, 1:4, 1:6, 1:8, 1:10). The solid dispersions were prepared by solvent method. The pure drug and solid dispersions were characterized by in vitro dissolution study. Distilled water was used as dissolution media, 1000 ml of distilled water was used as dissolution medium in each dissolution basket at a temperature of 37°C and a paddle speed of 100 rpm. The very slow dissolution rate was observed for pure Diazepam and the dispersion of the drug in the polymers considerably enhanced the dissolution rate. This can be attributed to improved wettability and dispersibility, as well as decrease of the crystalline and increase of the amorphous fraction of the drug. SEM (Scan-ning Electron microscope) studies shows that the solid dispersion having a uniform dispersion. Solid dispersions prepared with PEG-6000, Poloxamer showed the highest improvement in wettability and dissolution rate of Diaze-pam. Solid dispersion containing polymer prepared with solvent method showed significant improvement in the release profile as compared to pure drug, Diazepam.