[16�C17] Hence, the objective was to develop a simple and cost-effective method for the analysis of cefdinir. The International selleck Conference on Harmonization (ICH) guidelines require that stress testing be carried out to elucidate the inherent stability characteristics of the active substances. It suggests that degradation products that are formed under a variety of conditions should be identified and the degradation pathway established. It is stated that testing should include the effect of temperature, humidity, oxidation, photolysis, and acid and base hydrolytic conditions. An ideal stability-indicating method is the one that quantifies the drug per se and also resolves its degradation products. Stability is considered to be one of the most important criteria in pharmaceutical quality control.
Only a stable preparation would promise precise delivery of the drug to the patients. Expiration dating on any drug product is based on scientific studies at normal and stressed conditions. With this background, an attempt has been made to develop and validate a stability-indicating RP-HPLC method, for the accurate quantitation of cefdinir in bulk drugs, in the presence of its degradation products. EXPERIMENTAL Reagents and materials Cefdinir bulk drug (98% pure) was supplied by Glenmark Pharmaceuticals Ltd. (Mumbai, India). Acetonitrile and methanol (HPLC grade) were procured from Merck (Darmstadt, Germany). Deionized and ultra pure water (Millipore grade) used in all experiments was obtained from Milli-Q System (USA). The 0.45-��m Nylon pump filter was obtained from Advanced Microdevices (Mumbai, India).
Orthophosphoric acid, used for adjusting the pH of the buffer solution (AR grade), was procured from (S. D. Fine Chemicals). Sodium hydroxide (NaOH), hydrochloric acid (HCl), and hydrogen peroxide (H2O2) (all AR grade) were purchased from Qualigens Fine Chemicals (Mumbai, India). Instruments The instrument used was the Shimadzu (Japan) Liquid Chromatographic system, equipped with an LC-10AT, VP pump, and a photodiode array detector system (SPD-10A, VP). The output signal was monitored and processed using Clarity software on a Pentium computer (HCL-Mumbai).The column used was Waters RP Spherisorb C-18 (250 mm �� 4.6 mm i.d. �� 5 ��m particle size) Chromatographic conditions Chromatographic separation was achieved at room temperature on a reverse phase column, using a mobile phase consisting of orthophosphoric acid in water (pH 3.
0) : acetonitrile : methanol in a ratio of 13 : 5 : 2 (v/v/v). Before use it was filtered through a 0.45-��m Nylon filter and degassed in an ultrasonic bath. The flow rate was set at 1.0 mL min-1. The injection volume was 20 ��L and ultraviolet (UV) detection was performed at 286 nm. For Dacomitinib analysis of samples from forced degradation, a photodiode-array detector was used in scan mode, in the range of 200 �C 400 nm. Preparation of the mobile phase HPLC grade water of 650 mL (pH adjusted to 3.