Microbial quality of some herbal solid dosage forms

Herbal remedies are widely used for the treatment and prevention of various diseases and often contain highly active pharmacological compounds. These products have the potential of contamination withdifferent microorganisms. This is due to raw materials contamination and unhygienic production conditions. In this study, microbiological quality of some herbal solid dosage forms from public markets, in the city of Sari, Iran was examined. 20 herbal products as tablet, powder and capsule wereprepared. The products were evaluated for microbial contamination by USP (United States Pharmacopoeia) microbial limit test for enumeration and identification. Total aerobic count showed that all products had more than 1100 microorganism per gram. Isolation and identification of microbialcontamination showed that all the samples were contaminated with Salmonella sp. and there was no evidence for contamination of the samples by Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. In conclusion, all the samples of herbal drugs evaluated did not generally meet the standards for microbial limits as specified in official monographs. Such products can adversely affect health status of consumers as well as the stability of the products

Development and Evaluation of Mucoadhesive Chlorhexidine Tablet Formulations

Purpose: To formulate mucoadhesive chlorhexidine tablets and evaluate their drug release characteristics and mechanism.Methods: Chlorhexidine buccal adhesive tablets were prepared by direct compression using a blend of hydroxypropyl methylcellulose (HPMC) and chitosan as the bioadhesive polymers. Their dissolutionproperties were assessed according to USP 24 (paddle method). In order to determine the mode of drug release from the tablets, the release data were subjected to various release kinetic models. Thebioadhesive strength of the tablets was also evaluated. Results: The results showed that as the proportion of HPMC in the blend increased, drug release rate decreased, with the lowest release rate observed when HPMC alone was used as the bioadhesive polymer (p < 0.001). Both the type and ratio of the polymers used influenced release kinetics. Also,bioadhesion force increased with increasing proportion of HPMC in the tablets, with the highest adhesion force shown when HPMC was the only polymer used, and lowest when chitosan was used alone (p < 0.01). Conclusion: The chlorhexidine formulations developed showed promise as a bioadhesive delivery system for the drug.Keywords:  Mucoadhesive tablets; Chlorhexidine; HPMC; Chitosan; Release properties; Bioadhesive strength

Influence of Hydroxypropyl Methylcellulose Molecular Weight Grade on Water Uptake, Erosion and Drug Release Properties of Diclofenac Sodium Matrix Tablets

Purpose: To comparatively evaluate the effect of two hydroxylpropyl methylcellulose (HPMC) molecular weight grades (K4M and K15M) on drug release from diclofenac sodium matrix tablets.Methods: Tablets containing diclofenac sodium were prepared by direct compression method at various drug/HPMC ratios and evaluated in vitro for their water uptake, erosion and dissolution characteristics over a period of 8 h. Their release data were analyzed according to various release kinetic models.Results: The release rate of diclofenac decreased with increase in polymer content and was dependent on the HPMC type used, with the lower release rate observed in formulations containing the higher molecular weight grade HPMC K15M. Formulations containing the higher molecular weight HPMC (F4, F5 and F6) showed higher water uptake than those containing the lower molecular weight polymer (F1, F2 and F3) (p &lt; 0. 001). The formulations incorporating the lower molecular weight HPMC K4M (F1, F2 and F3) showed higher erosion than those that contained HPMC K15M (F4, F5 and F6) (p &lt; 0.001). Kinetic data based on the release exponent, n, in Peppas model, showed that n values were between 0.14 and 0.55, indicating that drug release from HPMC matrices was predominantly by diffusion.Conclusion: This study demonstrates that the molecular weight (MW) of HPMC does affect the water uptake and erosion as well as the rate of drug release from of HPMC matrices.Keywords: Matrix, Diclofenac sodium, HPMC, Erosion, Water uptake

Effect of Hydroxypropyl Methylcellulose and Ethyl Cellulose Content on Release Profile and Kinetics of Diltiazem HCl from Matrices

Purpose: To develop a oral controlled matrix drug delivery system for a highly water soluble drug, diltiazem HCl, and investigate its drug release mechanism. Method: Diltiazem HCl was chosen because of its high water solubility. Tablets containing the drug were prepared by direct compression method using different matrix ratios of ethyl cellulose (EC) and hydroxypropyl methylcellulose (HPMC). The formulations were evaluated in vitro for their dissolution characteristics over a period of 8 h. Drug release was analysed according to various release kinetic models. Results: The results showed that these polymers slowed down the release of diltiazem HCl from the matrices. In the presence of EC, increasing the concentration of HPMC decreased the release rate of diltiazem. Furthermore, incorporation of EC in tablets with HPMC as the matrix was found to control drug release. Kinetic analysis showed that drug release from three of the formulations was adequately described by zero order model. Conclusion: The formulations developed could potentially be used for controlled delivery of highly soluble drugs such as diltiazem HCl

Effect of Hydroxypropyl Methylcellulose and Ethyl Cellulose Content on Release Profile and Kinetics of Diltiazem HCl from Matrices

Purpose: To develop a oral controlled matrix drug delivery system for a highly water soluble drug, diltiazem HCl, and investigate its drug release mechanism. Method: Diltiazem HCl was chosen because of its high water solubility. Tablets containing the drug were prepared by direct compression method using different matrix ratios of ethyl cellulose (EC) and hydroxypropyl methylcellulose (HPMC). The formulations were evaluated in vitro for their dissolution characteristics over a period of 8 h. Drug release was analysed according to various release kinetic models. Results: The results showed that these polymers slowed down the release of diltiazem HCl from the matrices. In the presence of EC, increasing the concentration of HPMC decreased the release rate of diltiazem. Furthermore, incorporation of EC in tablets with HPMC as the matrix was found to control drug release. Kinetic analysis showed that drug release from three of the formulations was adequately described by zero order model. Conclusion: The formulations developed could potentially be used for controlled delivery of highly soluble drugs such as diltiazem HCl