Greening microwave-assisted digestion method using hydrogen peroxide for determination of elemental impurities by ICP-OES in antihypertensive active pharmaceutical ingredients.

Microwave-assisted wet digestion (MAWD) using only HO was proposed for oxidizing active pharmaceutical ingredients (APIs) for hypertension treatment and subsequent determination by inductively coupled plasma optical emission spectrometry (ICP-OES). Diltiazem hydrochloride (DIL) presented the most refractory characteristic for oxidation using MAWD-HO. This proposed MAWD-HO method was validated for specificity, accuracy, and precision according to United States Pharmacopeia (USP) Chapter 233 guidelines.