Estimation of Glycopyrrolate by Analytical Quality by Design Supported Difference UV Spectrophotometric Method
A novel difference UV spectrophotometric method was developed and validated for estimation of glycopyrrolate (GLP) in injection formulations using analytical quality by design approach. GLP shows two different absorbance maxima in 0.1M HCl and 0.1M NaOH. Principle of difference spectroscopy was utilized to avoid the variation in absorbance maximum and amplitude of analyte solutions were measured keeping analyte in 0.1M HCl in reference cell and analyte in 0.1M NaOH in sample cell. The amplitude was measured considering maxima at 219nm and minima at 233nm. Further, analytical quality by design approach proved worthy by ensuring method robustness prior to method development. Scanning speed and sampling interval were the two variables which were studied for the robustness purpose using an experimental design. The method validation studies were carried out to evaluate linearity, accuracy, precision, sensitivity etc. The method was applied successfully for estimation of GLP in bulk and present in injections.