Development of a Discriminative Intrinsic Dissolution Method for Efavirenz

Abstract

Efavirenz is a poorly water-soluble drug categorized as a Class 2 drug under the Biopharmaceutics Classification System (BCS). Intrinsic dissolution is an effective tool for evaluating the physical–chemical properties of an active pharmaceutical ingredient (API). The aim of this study was to develop an intrinsic dissolution method for use in quality control of efavirenz to be used in the selection of an API for the production of dosage forms. The influence of compression force, rotation speed, dissolution medium, and surfactant concentration on the intrinsic dissolution rate (IDR) of efavirenz were evaluated using a rotating-disk holder. The developed method was applied to the evaluation of batches using different raw materials (batches A–G). Dissolution media containing 0.5% sodium lauryl sulfate (SLS) and a rotation speed of 100 rpm proved the most discriminative. Batches A, D, and F provided intrinsic dissolution rate (IDR) values greater than 36 μg/min/cm2 in this medium, while batches B and E provided IDR values of approximately 31 μg/min/cm2. The IDRs obtained showed a high correlation with the surface areas of the batches. The method may be used in the development of efavirenz formulations to select API with physical–chemical properties that enable appropriate dosage form dissolution.