Development and validation of PCR, PLS, and TLC densitometric methods for the simultaneous determination of vitamins B(1), B(6) AND B(12) in pharmaceutical formulations.

This work represents the simultaneous determination of thiamine hydrochloride (B(1)), pyridoxine hydrochloride (B(6)) and cyanocobalamine (B(12)) by two different methods namely spectrophotometry multivariate calibration and densitometry. The spectrophotometric numerical method depends on the use of spectrophotometric data coupled to PLS and PCR multivariate calibration methods for the simultaneous determination of (B(1)) and (B(6)) in the presence of (B(12)) in laboratory prepared mixtures and commercial tablets. A calibration set was prepared, where the three vitamins were modeled using a full factorial 23 with three center points experimental design. This calibration set was used to build the PLS and PCR models. The models were validated by testing their predictive ability on a validation set where low RMSEP, RSEP % were obtained for both models. Figures of merit were determined using the net analyte signal concept. The proposed models were applied successfully to simultaneous determination of B1 and B6 in presence of a low concentration of B12 in pharmaceutical dosage forms that contain simple excipients. The TLC densitometric method was based on the use of a developing system of chloroform: ethanol: water: acetic acid solution (2: 8: 2: 0.5 v/v) to separate the three vitamins. The separated spots were scanned at 242nm, 291nm and 360nm for B(1), B(6) and B(12) respectively. The proposed method was applied successfully to simultaneous determination of the three vitamins in their pure powder form in the range 0.1-1.5 (µg/spot), 0.5-3.5 (µg/spot), 0.1-1.5 (µg/spot) for B(1), B(6), and B(12) respectively and in their pharmaceutical formulations.