Abstract
A three point geometrical correction method was proposed for the estimation of Hydrochlorothiazide and Clonidine hydrochloride from biological samples. The geometrical correction method was developed which eliminates or reduces the background irrelevant absorption that may be present in samples of biological origin.The method was developed using egg albumin as biological media at three wavelengths 317nm, 269nm and 226nm for Hydrochlorothiazide and 315nm, 280nm and 296nm for Clonidine HCl. The proposed method showed linearity at three wavelengths in the range of 6-14 µg/ml and 2-10µg/ml with regression coefficient of 0.993, 0.999 and 0.995 for Hydrochlorothiazide and 0.992, 0.993 and 0.986 for Clonidine HCl respectively.This proposed method was statistically validated in accordance with ICH guidelines. The method was found to be accurate, precise, rugged and robust as indicated by low values of % RSD. The % RSD for Hydrochlorothiazide at three wavelengths was 0.36, 0.73 and 0.55 and for Clonidine HCl was 0.45, 0.48 and 0.80. For the biological media, corrected absorbance (D value) was calculated and found to be constant for specified concentration. The D value showed linear relationship with concentration showing regression coefficient as 0.996 and 0.991 for Hydrochlorothiazide and Clonidine HCl respectively. A simple three point geometrical correction UV Spectrophotometric method was developed and validated as per ICH guidelines using egg albumin as biological medium for estimation of Hydrochlorothiazide and Clonidine HCl
