Spectrophotometric Quantitative Estimation of Lornoxicam and Paracetamol in Bulk Drugs and Dosage Form

Two accurate, precise, sensitive and economical spectrophotometric methods were developed and validated for simultaneous estimation of Lornoxicam and Paracetamol in tablet dosage form. These methods were developed based on the simultaneous estimation of drugs in a binary mixture without previous separation. The methods employed were Absorbance Ratio Method (QAnalysis) (I) and Simultaneous Equation Method (Vierodt’s Method) (II). The first method employs 271.5 nm as λ1 (Isobestic point) and 286 nm as λ2 (λmax of Lornoxicam) for formation of equations. The second method employs estimation of a drug concentration by selecting λmax where the absorbances of these drugs were maximum. So λmax for Lornoxicam and Paracetamol is 286 nm and 257 nm respectively. Lornoxicam and Paracetamol obey Beer’s law in the concentration range 8-40 μgmL-1 (r2=0.9998) and 10-50 μgmL-1 (r2=0.9999) in 0.1 N NaOH. The mean recovery for Lornoxicam and Paracetamol were found to be 98.38±1.28% and100±0.50% from method I and 100.33±0.56% and100±0.40% from method II. The developed methods were validated according to ICH guidelines and values of accuracy, precision and other statistical analysis were found to be in good accordance with the prescribed values. Thus the proposed methods were successfully applied for simultaneous determination of lornoxicam and paracetamol in routine industrial work.