An RP-HPLC method for simultaneous separation and quantification of pantoprazole and its five main impurities in pharmaceutical formulations was developed and validated. The separation was accomplished on a Zorbax Eclipse XDB C18 column (5 m particle size, 150 4.6 mm id) using a gradient with mobile phase A [bufferacetonitrile (70 + 30, v/v)], and mobile phase B [bufferacetonitrile (30 + 70, v/v)]. The buffer was 0.01 M ammonium acetate solution with addition of 1 mL triethylamine/L of the solution, adjusted to pH 4.5 with orthophosphoric acid. The eluent flow rate was 1 mL/min, the temperature of the column was 30C, and the eluate was monitored at 290 nm. Linearity (r = 0.999), recovery (97.6105.8), RSD (0.551.90), and LOQ (0.0991.48 g/mL) were evaluated and found to be satisfactory. The proposed method can be used for simultaneous identification and quantification of the analyzed compounds in pharmaceutical formulations.

A simple and rapid ultra-high performance liquid chromatographic (UHPLC) method for the separation and determination of oxcarbazepine and its related substances in tablets, was developed. Chromatographic separation of oxcarbazepine from its related substances (degradation and by-products) was achieved on a reversed phase C 18 column (Pinnacle DB C18, RESTEK, 100 x 2.1 mm, 1.9 µm particle size) using gradient program with water (as mobile phase A) and acetonitrile (as mobile phase B), at a flow rate 0.5 mL min-1 and UV detection at 254 nm. The column temperature was 30°C.The method has good selectivity towards oxcarbazepine and its related substances. The accuracy of the method for oxcarbazepine assay, expressed as mean recovery was 101.8 %, and of the method for quantification of degradation products was 95.9 %-103.3 %. Limit of quantification for oxcarbazepine and its degradation products ranged from 0.60 µg mL-1 to 1.30 µg mL-1. The linearity range for oxcarbazepine assay was from 2.4 to 3.60 mg mL-1 (R 2 =0.999). Mean value for oxcarbazepine assay from the tablets was 299.92 mg (label claim 300 mg). The method can be used for routine analysis and the quality control of oxcarbazepine drug substance and its formulated products.

Summary.A simple ion chromatographic (IC) method was developed and validated for simultaneous or individual determination of zoledronic, alendronic, pamidronic acids and their related substances in pharmaceutical formulation. The analytes were separated on Waters IC-Pak Anion HR analytical column with a nitric acid (3 mM) without any other additives, as mobile phase at a flow rate of 1.0 mL min −1 . Inverse UV detection was used at 240 nm. Important chromatographic factors that influence the chromatography responses were screened by 11/12 Pluckett-Burman design and their interaction were assayed by 2 3 full factorial design. The RP-HPLC method was optimized with the aid of LC-Simulator ® (ACD Labs, Toronto, Ontario, Canada) software. Validated method was successfully used for quantitative analysis of PAMIFOS ® , concentrate for infusion (Habitfarm AD, Ivanjica, Serbia), ZOMETA ® , powder for infusion (Novartis Pharma, Stein AG, Switzerland) and BONAP ® tablets (Hemofarm, Vrsac, Serbia). Total chromatographic analysis time per sample was approximately 6 min, which represents significant improvement over existing methods. Validation studies revealed that the method is specific, rapid, reliable, and reproducible. Calibration plots were linear over the concentration ranges 20-120 μg mL −1 and 0.1-2 μg mL −1 for bisphosponates and their related substances, respectively. The LODs were 8.7, 4.7, 2.5, 0.026 and 0.011 μg mL −1 for alendronate, pamidronate, zoledronate, phosphoric acid and phosphorous acid, respectively.