Method to recover a lipophilic drug from hydroxypropyl methylcellulose matrix tablets

Abstract

A reverse-phase high-performance liquid chromatographic (HPLC) method for recovery of the lipophilic drug, alprazolam, from matrix tablets containing the hydrophilic polymer hydroxypropyl methylcellulose (HPMC) was developed. Lipophilic drugs, such as alprazolam, are difficult to completely extract and quantitate from tablets containing HPMC polymer. The percentage of recoveries of alprazolam from placebo powder spiked with alprazolam stock solution and from placebo powder mixed with alprazolam powder were about 100% and 85% to 95%, respectively. The validated method using water to completely dissolve HPMC before the addition of a strong solvent to dissolve and extract the drug from the HPMC solution was shown to be the most reproducible method. Different molecular weight distributions of the HPMC polymer, such as HPMC-K4M and HPMC-K100LV, did not influence the dissolution results of alprazolam using this validated method. Similarly, the excipients composing the matrix tablet formulations, such as dicalcium phosphate dihydrate, dicalcium phosphate anhydrous, calcium sulfate dihydrate, sucrose, dextrose, and lactose monohydrate, did not influence the percent recovery of alprazolam. The recovery method reported herein was shown to be the most efficient to achieve complete recovery of alprazolam from powder blends and tablets containing a variety of excipients and different grades of HPMC.