STUDY OF DRUG-DRUG INTERACTION AND SIMULTANEOUS ESTIMATION OF A NEW COMBINATIONAL DRUG BY DSC AND HPLC
Concurrent administration of more than one drug is a common practice in medical science and that case one drug may interacts with another causes side effects in human health. This research article intentionally produces drug-drug interaction to develop and validate a new RP-HPLC method for simultaneous estimation of a new combinational drug of Valsartan and Ciprofloxacin HCl. First, two homogeneous multi drug mixtures [mixture-A (valsartan, naproxen, lercanidipine, cefepime and metformin HCl) and mixture-B (ramipril, naproxen, lercanidipine, ciprofloxacin HCl and gliclazide BP)] were studied at molar ratio of 1:1 for drug interaction by DSC and HPLC. The DSC thermo gram of mixture A and B shown sharp melting endotherm at 62.90°C, 104.05°C & 327.86°C and at 59.77°C & 105.51°C respectively. In HPLC, only one retention time found at 6.431 ± 0.1 for mixture-A and two retention time at 6.373 ± 0.1 and 7.196 ± 0.1 for mixture-B, under the condition of 2% acetic acid (PH 2.70) and acetonitrile (30:70, v/v) at 215nm and 254nm. But at same condition when the 5% acetic acid (PH 3.45) used, no sharp peaks observed for both mixtures. That indicates strong interactions due to bond breaking and forming among the drugs. Second, for development and validation of a new RP-HPLC method a C-18 bonded silica column (250 x 4.6 mm, 5μ) was used with a mobile phase comprising of 2% acetic acid and acetonitrile (40:60, v/v) with flow rate 0.70 mL/min at 240 nm. The retention times found at 2.770 ± 0.1 min and 8.647 ± 0.1 min, the correlation coefficient found at 0.9993 and 0.9991 and the percentage recovery found 98.48% and 101.70% for ciprofloxacin HCl and valsartan respectively. The % RSD values found for ciprofloxacin HCl as 0.80-1.83 and valsartan as 0.41-1.33 by observing both intra and inter day.