Microwave-assisted extraction of active pharmaceutical ingredient from solid dosage forms

The microwave assisted extraction (MAE) technique has been evaluated for the extraction of active pharmaceutical ingredients (API) from various solid dosage forms. Using immediate release tablets of Compound A as a model, optimization of the extraction method with regards to extraction solvent composition, extraction time and temperature was briefly discussed. Complete recovery of Compound A was achieved when samples were extracted using acetonitrile as the extraction solvent under microwave heating at a constant cell temperature of 50 °C for 5 min. The optimized MAE method was applied for content uniformity (single tablet extraction) and potency (multiple tablets extraction) assays of release and stability samples of two products of Compound A (5 and 25 mg dose strength) stored at various conditions. To further demonstrate the applicability of MAE, the instrumental extraction conditions (50 °C for 5 min) were adopted for the extraction of montelukast sodium (Singulair®) from various solid dosage forms using methanol–water (75:25, v/v) as the extraction solvent. The MAE procedure demonstrated an extraction efficiency of 97.4–101.9% label claim with the greatest RSD at 1.4%. The results compare favorably with 97.6–102.3% label claim with the greatest RSD at 2.9% obtained with validated mechanical extraction procedures. The system is affordable, user-friendly and simple to operate and troubleshoot. Rapid extraction process (7 min/run) along with high throughput capacity (up to 23 samples simultaneously) would lead to reduced cycle time and thus increased productivity.