Search

Tioconazole (TCN) (anti fungal) is commonly co-formulated with tinidazole (TND) (antiprotozoal), hydrocortisone acetate (HYD) (anti infalmmatory) and benzyl alcohol (BZL) (preservative) in different pharmaceutical preparations. Tioconazole has three related impurities namely; tioconazole related impurities A, B and C (TCN-RA), (TCN-RB) and (TCN-RC), respectively. As the main purpose of a test for related substances is to control degradation impurities and to limit impurities arising during the synthesis of active ingredients and on the other hand, high efficiency and less elution are the basic requirements of high-speed chromatographic separation. So, two simple, precise, and accurate reversed-phase HPLC-UV and UPLC-DAD methods have been developed and compared for simultaneous estimation of TND, BZL, HYD and TCN in bulk and pharmaceutical formulations in the presence of TCN related impurities. A Eurospher C18 (250 mm × 4.6 mm, 5 μm) for HPLC method and an Eclipse plus C18 (100 × 2.1 mm, 1.7 μm) for UPLC method were used. An isocratic mobile phase consisted of 20 mM anhydrous KH2PO4(containing 0.2% TEAv/v), pH adjusted to 6 with orthophosphoric acid: acetonitrile, (25:75,v/v) for HPLC method and a gradient mobile phase of 20 mM anhydrous KH2PO4(containing 0.2% TEAv/v), pH adjusted to 6 with orthophosphoric acid and acetonitrile mixed in different proportions for UPLC method, were prepared. Flow rate was set at 1.0 mL min-1and 0.3 mL min-1for HPLC and UPLC methods, respectively and the detection was performed for both methods at 295 nm, 210 nm, 245 nm and 225 nm for TND, BZL, HYD and TCN and its related impurities, respectively. The propsed UPLC-DAD method had advantages, of being economic on the large scale with relatively much satisfactory results for linearity, sensitivity and specificity. The two proposed methods are applicable for the purity assessment of TCN in bulk, vaginal tablets and creams. [ABSTRACT FROM PUBLISHER]

Aspirin (ASP) and cilostazol (CST) are used as a combination in pharmaceutical formulations for treatment of strokes. Salicylic acid (SAL) is considered to be one of the main synthesis impurities and a degradation product of ASP. On the other hand, the main related impurities of CST are CST related A, B, and C (CST-RA, CST-RB, and CST-RC), respectively. Furthermore, as high efficiency and less elution are the basic requirements of high-speed chromatographic separation, so, a comparative study of two simple, precise, and accurate reversed-phase HPLC and UPLC methods was developed and validated for simultaneous estimation of ASP and CST in bulk and capsules in the presence of SAL, CST-RA, CST-RB, and CST-RC. A Eurospher II C18 (250 × 4.6 mm2, 5 µm) for HPLC method and an Agilent Zorbax Eclipse Plus C18 (50 × 2.1 mm2, 1.8 µm) for UPLC method were used. A gradient mobile phase of 20 mM anhydrous KH2PO4buffer solution (containing 0.2% triethylamine (TEA), v/v) with pH adjusted to 2.9 using orthophosphoric acid (solution A) and acetonitrile (solution B) mixed in different proportions for HPLC and UPLC methods was prepared. Flow rate was set to 1.0 and 0.3 mL min−1for HPLC and UPLC methods, respectively, and the detection was performed for both methods at 210 nm. It worth noting that the proposed UPLC-DAD assay exhibited relatively much more precision, sensitivity, specificity, and economic and chromatographic separation superiority than proposed HPLC-UV assay. Both developed methods were compared with reference methods to prove its applicability and are suitable for purity assessment of ASP and CST in bulk and capsules. [ABSTRACT FROM PUBLISHER]