Development and validation of RP HPLC method for determination of betamethasone dipropionate in gingival crevicular fluid

A simple RP HPLC method for quantification of betamethasone dipropionate (BDP) in gingival crevicular fluid (GCF) has been developed and validated. GCF represents a valuable matrix for therapeutic monitoring of drugs used in the treatment of periodontal disease. The proposed method involves single step extraction for sample preparation. The calibration curve for BDP was linear over the concentration range of 0.10-2.00 μg mL^-1 (R² = 0.9971). RSD values of intra- and inter-day precision ranged 2.2-4.5 and 1.6-5.7 %, while accuracy values were higher than 96.6 and 97.0 %, respectively. The described method can be successfully applied for determination of betamethasone concentrations in GCF obtained from patients with chronic periodontitis after local treatment with BDP cream 0.5 mg g^-1.