Development and validation of method for the estimation of tacrolimus crystalline API in tacrolimus extended release capsules 0.5mg, 1mg and 5mg by power X-ray diffractometer (PXRD)

A PXRD quantitative method is developed^[1] for the Quantitation of % Tacrolimus crystalline in Tacrolimus Extended Release capsules using PXRD. The PXRD conditions for the Slow scan method developed for the estimation of % Tacrolimus crystalline, with a radiation source of Copper K_α1 (λ = 1.54060A°). The Angular range was 9.65 to 10.80° 2θ, with the Voltage and Current set to 40kV and 40mA and a step size of 0.02° along with sample rotation of 15rpm. The scan type is Locked coupled, continuous with a high sensitive Lynxeye XET detector. The developed method^[2] was validated^[3] for Specificity, Sensitivity (LOD and LOQ), Linearity, Accuracy and Robustness. The PXRD method is Linear with a concentration range of 0.2% to 1.0% with correlation coefficient of 0.996. The recoveries ranged between 83% - 110% for 0.2%, 0.6% and 1.0% levels. The XRD Method was found to be specific, linear, sensitive, accurate and robust for the estimation of % Tacrolimus Crystalline in Tacrolimus Extended Release capsules 0.5mg, 1mg and 5mg.