The cream is effective for treating the warts or lesions without scarring the skin.10 Chemical structure of Imiquimod is shown in Fig. 1. Literature survey revealed that there is no any HPLC method reported for determination of imiquimod content in imiquimod cream. For imiquimod active pharmaceutical ingredient (API) and for some biological samples, few methods were reported but no method has been reported for imiquimod topical preparations (imiquimod creams). This proposed method is very simple and rapid for quality analysis of imiquimod content in imiquimod cream. Imiquimod standard
and cream samples were obtained as a gift samples from Cipla Limited. Ortho phosphoric acid (GR grade), triethyl amine (GR Grade), potassium dihydrogen phosphate and hydrochloric acid (GR Grade) were purchased from qualigens. Selleckchem Carfilzomib HPLC grade Acetonitrile was obtained from Rankem. Auto sampler
high performance liquid Chromatograph Shimadzu 2010 equipped with software “class-vp” along with UV and PDA detector was used. Mobile phase was a mixture of 10 mM monobasic phosphate containing 0.1% triethylamine adjusted to pH 2.45 with ortho phosphoric acid and acetonitrile in ratio of 70:30 v/v. Mobile phase was filtered through a 0.45 μm nylon filter and degassed for 5 min using an ultrasonicator. Mobile phase MEK inhibitor was pumped through the column at a flow rate of 1.4 mL min−1. Analyses were carried out at 40 °C temperature and eluents were monitored at detection wavelength of 245 nm.
The total run time was set as 5 min. The injection volume was 20 μl. Prior to the first injection; the column was equilibrated for 25 min with the mobile phase flowing through the system. Using these analytical conditions, imiquimod was eluted for about 3.0 min. Diluent was prepared by mixing 0.1 N HCl and acetonitrile in the ratio7:3 (v/v). Accurately weighed about 50 mg of imiquimod standard was taken in a 200 mL volumetric only flask. About 150 mL diluent was added and mixture was dissolved by sonication and it was diluted up to mark with diluents. 5 mL of this solution was further diluted to 100 mL with mobile phase. Cream sample equivalent to 50 mg of imiquimod was weighed and taken in a 200 mL volumetric flask to which 150 mL of diluent was added and the mixture was sonicated for 40 min with intermittent shaking and then cooled at room temperature. The resulting solution was diluted with diluent up to the mark. 5 mL of this solution was further diluted to 100 mL with mobile phase. Filtered solution through 0.45 μm Teflon syringe filter. Specificity of proposed method was determined by checking blank and placebo interference at the retention time of imiquimod peak. Identification of imiquimod peak in sample solution was confirmed by comparing retention time of imiquimod peak with retention time of standard solution of imiquimod. Also imiquimod peak was checked for peak purity using Photo diode array detector (PDA).