A Simple Liquid Chromatographic Method for Estimation of Glycopyrrolate in Pharmaceuticals Using Experimental Design

A liquid chromatographic method was developed and validated to estimate glycopyrrolate (GLP) present in pharmaceutical formulations. The method was developed using a C18 column with a mobile phase containing methanol: phosphate buffer (pH = 3.2) (65:35, %v/v) flowing at 1.0 ml min-1. GLP was detected at a wavelength of 224 nm. The method was found linear over a concentration range of 6-14 μg ml-1. Degradation studies proved the chromatographic method specificity. Validation studies were performed on the method acceptability and suitability for estimating GLP in bulk as well as injectables. The detection and quantitation limits were 2.5 μg ml-1 and 6.0 μg ml-1, respectively. Further, method precision was assured (%R.S.D. < 2%) using an experimental design approach through a factorial design. Also, it revealed that analyst skills are of critical importance and may influence the method preciseness. Overall, the method was reliable and of optimum quality and possessed the application potential in routine quality control of dosage forms of GLP and may serve as a basis for development of future bio-analytical methods.