BIOANALYTICAL METHOD FOR SIMULTANEOUS ESTIMATION OF RIBOCICLIB AND LETROZOLE AND ITS APPLICATION TO PHARMACOKINETIC STUDIES USING ULTRA-PERFORMANCE LIQUID CHROMATOGRAPHY

Objective: An easy, quick, precise, active and reproducible UPLC technique was developed for the bioanalytical method of Ribociclib and Letrozole using Lapatinib as the internal standard. Methods: This article summarizes the recent progress on bioanalytical UPLC method using phenyl column (100x2.1 mm, 1.7µ) column and an organic mobile phase of 0.1% Tri fluoro acetic acid and Acetonitrile in 50:50 with a flow of 0.5 ml/min. An injection volume of 5 microliters was used. Lapatinib was used as an internal standard. Results: The drugs were found at Letrozole (m/z 435.46/216.55), Ribociclib (m/z 506.34/167.43) and Lapatinib (internal standard, m/z 582.37/184.29), respectively. Tests were performed in less than five minutes on Ribociclib (r2 = 0.99953; concentration range: 2 to 40 ng/ml) and Letrozole (r2 = 0.99915; concentration range: 0.025 to 0.5 ng/ml). The study's precision and recovery results were determined to be accurate. Accuracy, precision, recovery, matrix effect and stability results were found to be within the suitable limits. Simple and efficient method was developed and utilized in pharmacokinetic studies to see the investigated analyte in body fluids. Conclusion: The application denotes all the parameters of system suitability, specificity, linearity and accuracy are in good agreement with USFDA guidelines and applied effectively for the investigation of pharmacokinetic studies in rabbit