An Integrative QbD Approach for the Development and Optimization of Controlled Release Compressed Coated Formulation of Water-Soluble Drugs

Abstract

Controlled release dosage forms maintain regulated pharmacokinetic profile of drug substance within its therapeutic window by ensuring constant plasma concentrations. Controlled release formulations not only increase the therapeutic efficacy of drug substances but also reduce their dose-related side effects. Present investigation was conducted to develop, optimize, and validate compressed coated controlled release tablet formulation for highly water-soluble drug substances which have no rate-controlling factor towards its release from dosage form. Drug dispersed waxy core tablet, press coated within the swellable hydrophilic polymeric barrier layer, was developed and optimized via quality by design approach (QbD) using Box-Behnken design. The optimized formulation was characterized and validated using in vitro quality control parameters. Attributes identified under SUPAC guidelines, such as drug release rates at 30 min, 6 h, and 12 h, were considered as the critical quality attributes (CQAs) that significantly affected efficiency of the compressed coated controlled release tablets. CQAs screened using risk assessment and Pareto chart analyses were used for optimizing controlled release dosage form. Findings revealed that tablets containing drug to wax ratio of 1:1, hydrophilic swellable polymer concentration of 200 mg, and prepared using compression pressure of 6.5 kg/cm² exhibited the highest desirability indices in terms of controlling the release rate of drug substance. Optimized formulation was also evaluated for swelling rate, erosion rate, and other post-compression parameters, including release kinetics. Fickian diffusion-based zero-order controlled release of BCS class I drug substance was achieved through the developed dosage form.

Keywords: BCS class I drug substance; Box-Behnken design; compressed coated tablets; controlled release tablets; metoprolol succinate; quality by design (QbD); zero-order release.