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Some excipients are currently available for the formulation of pharmaceutical suspensions. The objective of this study is to develop cheap and effective starch-based excipient that can be used as an effective alternative for the formulation of pharmaceutical suspensions. Carboxymethylated Plectranthus edulis, Vatke (P. edulis) [fam., Lamiaceae], starch was evaluated as a suspending agent in metronidazole benzoate suspensions in comparison with sodium carboxymethyl cellulose (NaCMC) at a concentration range of 1-4% (w/v). The resulting suspensions were evaluated for their sedimentation volume (%), degree of flocculation, rheology, redispersibility, and dissolution rate. Stability studies were performed for 3 months. The apparent viscosities of the formulations prepared with carboxymethylated P. edulis starch at reaction condition E (CMPS-E) was significantly lower than that of NaCMC (p < 0.05). The flowability of the suspensions, at all concentration levels of the suspending agents, were in the order of CMPS-E > NaCMC. AT 1% concentrations, carboxymethylated P. edulis starch (76 ± 1.5%) provided significantly higher (p < 0.05) sedimentation volume than NaCMC (40 ± 1.5%). At 3% and 4%, both gave comparable sedimentation volume (100%). Potassium dihydrogen phosphate (KH 2 PO 4) employed as a flocculating agent significantly increased (p < 0.05) the sedimentation volume of the suspensions prepared with carboxymethylated P.edulis starch and NaCMC. The redispersibilities of CMPS-E were better than those of NaCMC. All suspensions showed a release of greater than 85% of drug within 1 h. The results of stability studies showed that all suspension formulations were stable. From the foregoing, it can be concluded that carboxymethylated P. edulis starch could be used as an alternative suspending agent.

Carboxymethylated Plectranthus edulis, Vatke (P. edulis) [fam., Lamiaceae] starch was evaluated as a suspending agent in metronidazole benzoate suspensions in comparison with sodium carboxymethyl cellulose (NaCMC) at concentration range of 1-4% (w/v). The resulting suspensions were evaluated for their sedimentation volume (%), degree of flocculation, rheology, redispersibility, and dissolution rate. Stability studies were performed for 3 months. The apparent viscosities of the formulations prepared with carboxymethylated P. edulis starch at reaction condition E (CMPS-E) was significantly lower than that of NaCMC (p < 0.05). The flowability of the suspensions, at all concentration levels of the suspending agents, were in the order of CMPS-E > NaCMC. AT 1% concentrations, carboxymethylated P. edulis starch (76 ± 1.5%) provided significantly higher (p < 0.05) sedimentation volume than NaCMC (40 ± 1.5%). At 3% and 4%, both gave comparable sedimentation volume (100%). Potassium dihydrogen phosphate (KH2PO4) employed as a flocculating agent significantly increased (p < 0.05) the sedimentation volume of the suspensions prepared with carboxy-methylated P.edulis starch and NaCMC. The redispersibilities of CMPS-E was better than those of NaCMC. All suspensions showed a release of greater than 85% of drug within 1 h. The results of stability studies showed that all suspension formulations were stable. From the foregoing, it can be concluded that carboxymethylated P. edulis starch could be used as an alternative suspending agent.

The aim of present work was to undertake comparative in vitro quality evaluation of six marketed clotrimazole cream formulations in Ethiopia with respect to physico-chemical properties like viscosity, spreadability, extrudability, pH and drug content. In vitro clotrimazole release from cream formulations was also studied using synthetic cellulose acetate membrane at 37 ºC in a solvent containing methanol and PBS 7.4 in the ratio of 75:25 as receiver medium. The cumulative amounts of the drug released over 12 h (µg mm-2) were analyzed. All clotrimazole cream formulations showed good and smooth homogeneous appearance with white color. The pH of clotrimazole cream formulations ranged from 4-7, which is a physiologically acceptable pH range and in principle devoid of any skin irritation. Clotrimazole content ranged from 90-110%, ensuring the uniformity of the drug content in all formulations. The increase in diameter of clotrimazole cream formulations following the spreadability test was found to range from 4-6 cm. Cream formulation D (Clotri-Denk) exhibited highest viscosity values than other formulations, whereas formulation E (Chinese Clotrimazole BP) showed lowest viscosity value. Cream formulation F (Mycoril) showed better extrudability and spreadability as compared to other formulations. Drug release from all formulations was slow in the first 6 hrs. After the 6 th hr, steady drug release continued for formulation D and E. Fast drug release was observed in formulations A (Candid) and B (Candigen), whereas for the formulations C (Canesten), D and E, steady drug release pattern was observed after the 6 th hr. It can be concluded that all clotrimazole cream formulations fulfilled the quality criteria of in-house and pharmacopeias specifications.

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