Background: Rapamycin or Sirolimus is a macrolide compound which is used to coat coronary stents for the treatment of cardiovascular disease. The release of drug from the stent is very vital in treating the patients suffering from coronary heart problems. In the past various attempts were made to estimate Rapamycin using HPLC, LCMS, etc. in biological fluids. However, no significant work has been reported for its estimation in drug eluting stents using UV spectrophotometry. Hence the present study aims to develop a simple, reliable and cost effective UV spectrophotometric method for the evaluation of release of Rapamycin in drug eluting stents over a period of time. Method: The absorption maxima of Rapamycin was found to be at 278 nm and the method was validated for specificity, precision, linearity, accuracy and limit of quantification (LOQ) with different concentrations. The release of rapamycin in phosphate buffer saline (PBS) was noted for day 1,2,3,4 and 10. Results: The method is specific as the blank showed no interference with Rapamycin. The relative standard deviation (RSD) obtained from six replicates at 1µg/ml concentration is < 2 which indicates the method is precise. The method represents correlation coefficient (R2 =0.999) at concentration range of 0.2-10 μg/ml. The recovery was found to be 97.2 %. Conclusion: The above method is simple, reliable and cost effective. Hence it can be used in the routine analysis for the quantification of Rapamycin from drug eluting stents.
