Simultaneous Determination of Amoxicillin Trihydrate and Ambroxol Hydrochloride in Solid Dosage Form By Spectrophotometric and Stability Indicating RP-HPLC Method

Simple, accurate, and reproducible UV spectrophotometric and a stability indicating RP-HPLC method for simultaneous estimation of Amoxicillin Trihydrate (AMOX) and Ambroxol Hydrochloride (AMBRO) have been developed in the present work. The first developed method is Simultaneous equation method, wavelength selected are 228nm for amoxicillin and 245nm for ambroxol respectively. Linearity was observed in concentration range of 2- 12μg/ml for ambroxol and 20-120 μg/ml for amoxicillin. Second developed method is RP-HPLC method using Thermo C18 column (4.6 mm i.d × 250 mm) and acetonitrile: 0.025M potassium dihydrogen orthophosphate buffer (pH adjusted to 3 with orthophosphoric acid) in the ratio of 28:72% v/v as a mobile phase at a flow rate of 0.8 ml/min in the detection wavelength of 237 nm. For HPLC method, linearity was observed in the concentration range of 4- 24μg/ml for ambroxol and 25-200 μg/ml for amoxicillin. The correlation coefficients for both the methods obtained were near to 1. The accuracy of these methods were evaluated by recovery studies and good recovery results were obtained from 98 % to 102% for both the methods and the relative standard deviation of below 2% were achieved. The drugs were subjected to oxidation, hydrolysis, and heat to apply stress condition for degradation studies.