A simple Simultaneous UV Spectrophotometric Method to Determine Isoniazid and Rifampicin Contents in One Combined Tablet

Isoniazid and rifampicin are the first-line anti-tuberculosis drugs in the advanced phase. This study aimed at validating the method to determine the levels of isoniazid and rifampicin contents in one serve of combined tablet circulating at Pramuka market using simultaneous analysis of Ultraviolet Spectrophotometry with methanol as a solvent. The maximum wavelength of isoniazid and rifampicin obtained was 261 nm and 337 nm, respectively. The method used to confirm the validity here includes linearity, the limit of detection (LOD), limit of quantitation (LOQ), accuracy, and precision under the ICH guidelines. The results of the method validation for isoniazid and rifampicin were as follow: linearity (R2) in the range 5-25 µg / mL showed about 0.9998 and 0.9997, the limit of detection (LOD) 0.4026 µg/mL and 0.4952 µg / mL, and the limit of quantification (LOQ) 1.3421 µg / mL and 1.6508 µg / mL respectively. Besides, the accuracy-test (% recovery) was in the range of 100.44% ± 0.41% to 107.26% ± 0.28%, while the precision test (% RSD) was less than 2%. The determination of the contents was carried out on samples purchased at Pramuka Market with predetermined criteria and obtained levels of active ingredients ranging from 92.774% ± 0.39% to 103.51% ± 0.41%. The method validation to determine the levels of isoniazid and rifampicin contents in one serve of combined tablet using simultaneous analysis of Ultraviolet (UV) Spectrophotometry with methanol as a solvent is recommended for preparation analysis at the market.