Tablet powder containing 80 mg of promazine hydrochloride is ground to a paste with 10 ml of 2 M HCl. The paste is then diluted with 200 ml of water, shaken for 15 min and finally made up to 500 ml. A portion of the extract is filtered. Then, 5 ml of the filtrate is taken and diluted to 120 ml with 0.1 M HCI. - Absorbance reading=0.755 is read at a wavelength wavelength of 251 nm - A (1%, 1 cm) value of promazine.HCl at 251 nm=935 - Stated content of promazine.HCI per tablet=50 mg - Weight of 20 tablets=1.667 g - Weight of tablet powder taken for assay=163 mg expected content in tablet taken is: O97.78 g/ml expected content in tablet taken is: O97.78 g/mL O97.78 g/100ml 00.0097g/mL O97.78 mg/100ml Concentration in diluted tablet extract is: 0.81g/ml O80 g/100ml 00.00081g/mL 0.807 mg/100ml Concentration in original tablet extract is: O19.38g/ml 016.15 mg/100ml 019.38 mg/100ml 016.15 mg/ml Amount of promazine.HCl in original extract is: 096.90mg 080.75mg O96.90mg/100ml O80.75mg/100ml percentage of stated content 099.1 mg 080.75mg O99.1 mg/100ml 080.75mg/100ml