Development & Validation of an in Vitro Dissolution Method with Hplc Analysis for Betamethasone Acetate and Betamethasone Sodium Phosphate in Formulated Dosage Form

The intended purpose of this work is to develop and validate a dissolution test for betamethasone acetate and betamethasone sodium phosphate injectable suspension using a reverse-phase liquid chromatographic method. After testing sink conditions, dissolution medium and stability of the drug, the best conditions were: flow through cell of diameter 22.6 mm, 2.0 ml per minutes flow rate for 120 minutes, 500mL of sodium dihydrogen ortho phosphate buffer pH 7.4 with 2.5 % of sodium lauryl sulphate as dissolution medium, using a USP Apparatus IV (A flow through cell dissolution apparatus with seven cells dissolution tester Sotax CE7). The method was validated to meet requirements for a global regulatory filing and this validation included specificity, precision, linearity and accuracy. Release of more than 85% of the label amount was achieved over 60 min in the medium through out the study. The dissolution test developed was adequate for its purpose and could be applied for quality control of betamethasone acetate and betamethasone sodium phosphate formulation dosage form. INTRODUCTION: Dissolution test has emerged in the pharmaceutical field as a very important tool to characterize drug product performance . It provides measurements of the bioavailability of a drug as well as demonstrating bioequivalence from batch-to-batch. Besides, dissolution is a requirement for regulatory approval for product marketing and is a vital component of the overall quality control program . Betamethasone sodium phosphate (Fig. 1) and Betamethasone acetate (Fig. 2) are corticosteroids and are chemically known as Pregna-1, 4-diene-3, 20dione, 9-fluoro-11, 17-dihydroxy-16-methyl-21(phosphonooxy)-disodium salt, (11β, 16β)-.9-Fluoro11β, 17, 21-trihydroxy-16 β -methylpregna-1, 4-diene3, 20-dione 21-(disodium phosphate) [151-73-5] & Pregna-1, 4-diene-3, 20-dione, 9-fluoro-11, 17dihydroxy16methyl21(acetyloxy)-, (11β, 16β)-.9Fluoro-11β, 17, 21-trihydroxy-16βmethylpregna-1, 4diene-3, 20-dione 21-acetate [987-24-6]. FIG. 2: CHEMICAL STRUCTURE OF BETAMETHASONE SODIUM PHOSPHATE FIG. 2: CHEMICAL STRUCTURE OF BETAMETHASONE ACETATE