Implementation of Qbd Approach to Develop and Validate HPTLC Method for simultaneous estimation of Aliskiren, Amlodipine and Hydrochlorothiazide in Pharmaceutical Formulation

A High performance thin layer chromatographic method for simultaneous estimation of Aliskiren, Amlodipine besylate and Hydrochlorothiazide was developed and validated as per ICH guidelines. Moreover, robustness testing was performed applying a central composite design with k factor having 2 k factorial runs, 2k axial experiments and two center points. High performance thin layer chromatographic separation was performed on aluminium plates precoated with silica gel 60F 254 and acetonitrile: methanol: strong ammonis (10:10:0.1, v/v) as optimized mobile phase. The detection wavelength for simultaneous estimation of three drugs was 250 nm. The Rf values for Aliskiren, Amlodipine besylate and Hydrochlorthiazide were 0.54, 0.32 and 0.78 for, respectively. Percent recoveries in terms of accuracy for the marketed formulation was found to be 101.3-104.4, 100.7-104 and 101.5-103.9 for, Aliskiren, Amlodipine besylate and Hydrochlorthiazide, respectively. The pooled % relative standard deviation values for repeatability studies and intermediate precision studies was found to be less than 2% for Aliskiren, Amlodipine besylate and Hydrochlorthiazide, respectively. All these three factors (methanol content, developing distance and band size) were evaluated in the robustness testing by central composite design and these were found to have an insignificant effect on the retention factor. However, methanol content in total mobile phase as a factor appeared to have significant effect on robustness, compared to band size and developing distance and hence it is important to be carefully controlled. In summary, a novel, simple, accurate and reproducible high performance thin layer chromatographic method was developed, which would be of use in quality control of these tablets.