Formulation and Evaluation of Cephalexin Extended Release Matrix Tablets Using 32 Factorial Design

The aim of the present investigation was to prepare extended release film coated matrix tablets of cephalexin using binary mixture of two grades of hydrophilic polymer, hydroxypropyl methyl cellulose (HPMC), by direct compression method. Results of the preliminary trials indicated that the polymers used have significant release retarding effect on the formulation. To study the effect of concentration of polymers on drug release from matrix tablets, 32 full factorial design was applied. The concentration of HPMC K15M and HPMC 15cps were used as independent variables, while percentage drug release was selected as dependent variable. The dissolution data were fitted into zero-order, first-order, Higuchi and Korsemeyer–Peppas models to identify the pharmacokinetics and mechanism of drug release. Comparative study of dissolution profile of final batch F3 with market preparation (Sporidex AF 375) was done by similarity factor (f2) determination and it was concluded that final formulation F3 (10% HPMC K15M, 17.5% HPMC 15cps) shows good similarity with the market product. The results of the accelerated stability study of final formulation F3 for 1 month revealed that storage conditions were not found to have made any significant changes in final formulation F3. The release of cephalexin was prolonged for 6 h by using polymer combinations of HPMC and a twice daily matrix tablet was formulated

Attribute substitution in early enrollment decisions into Medicare prescription drug plans

Stand-alone outpatient prescription drug plans (PDPs), introduced in January 2006, have become the most popular source for coverage of outpatient prescription drugs under Medicare relative to other available Medicare plan types (e.g. Medicare Advantage drug plans). Using county-level enrollment figures from the Centers for Medicare & Medicaid Services linked to other public sources, we study attribute substitution in beneficiary decision-making with respect to PDP enrollment. To do so, we relate county-level PDP market share to county-level political support for the administration implementing the new benefit (the Bush Administration), controlling for socio-demographic and market characteristics. We find statistically significant evidence that greater support for the Bush administration is associated with increased PDP market share. Copyright © 2007 John Wiley & Sons, Ltd.