Four new hippurins, (22S,24S)-24-methyl-22,25-epoxyfurost-5-ene-3 -20 -diol (1), (22R,24S)-24-methyl-22,25-epoxyfurost-5-ene (2) and their respective 3 -acetates (3 and 4), have been isolated for the first time from the Indian Ocean soft coral Sarcophyton crassocaule.

No abstract

No abstract

A rapid, sensitive, and accurate ultra-fast liquid chromatographic method is developed for the determination of related substances and degradants of Solifenacin Succinate, an active pharmaceutical ingredient used in the treatment of overactive bladder. Chromatographic separation of Solifenacin Succinate, its related substances, and degradants was achieved using a Shimpack XR-ODS-II column and mobile phase system containing 10 mM potassium dihydrogen orthophosphate in water. The pH of the buffer was adjusted to 7.0 using triethyl amine (mobile phase A). LC-grade acetonitrile was used as mobile phase B, employing a binary-gradient program at a flow rate 0.5 mL/min. The resolution between the critical pair of peaks (Impurity A and analyte) was found to be greater than 3.5. The limits of detection and quantification (LOQ) of Impurity A, Impurity B, and the analyte were 0.2 and 0.6 μg/mL, respectively for a 5-μL injection volume. The percentage recovery of impurities in the presence of sample matrix ranged from 95 to 104 w/w. The test solution and mobile phase was observed to be stable up to 24 h after the preparation. The validated method yielded good results of precision, linearity, accuracy, robustness, and ruggedness. The proposed method is found to be rapid, accurate, and suitable for the quantitative determination of related substances and degradants during quality control of Solifenacin Succinate active pharmaceutical ingredient.

No abstract

No abstract

A single RP-HPLC method is developed for estimation of isomeric impurities of vitamin D3 analogueCalcipotriol/Calcipotriene (Calci) and impurities of Betamethasone dipropionate (BD). The developed method is capable of separating impurities of Calci and BD, specifically pre-Calcipotriene (Pre-Calci) from other known and unknown impurities. Pre-Calci is isolated and is characterised using few analytical techniques. These impurities are separated using a RP-C18 150 × 4.6 mm, 2.7 µm column maintained at 50˚C. The mobile phase consisted of mixture of water, methanol, acetonitrile and tetrahydrofuran eluted in gradient mode. Detection was done at 264 nm and 240 nm for Calci and BD impurities respectively. The method can be used for determining quality of Calci and BD drugs and ointment based drug products. It is stability indicating related substance method for both the drugs and drug products.

As over 70% of pharmaceutical compounds are bases, the analysis of these basic compounds by high performance liquid chromatography (HPLC) continues to be of great value and interesting. Acetyl cholinesterase inhibitors (AChEIs), which contain the basic compounds like Rivastigmine tartrate, Galantamine hydrobromide and Donepezil with different polarities, were chosen for the study. A rapid screening of the volatile ion-pairing reagents was performed using modern techniques like ultra high performance liquid chromatography (UHPLC). The experiments were planned using the 'Design of Experiments' (DoE) approach to identify the LC-MS compatible ion-pair reagent. In this study, Heptafluorobutyric acid (HFBA) has given a very good peak shape with tailing factor at 1.4 and theoretical plates up to *5,000 were observed, compared to tailing factor at 1.9 and theoretical plates up to *3,000 with non-volatile ion-pair reagent sodium heptane sulphonate (SHS). Similarly retention with HFBA was optimum as *5 min in short run time method compared to *13 min with SHS. This ion-pair reagent has proved to be good replacement of sodium alkyl sulphonate modifiers. HFBA can also be used for semi-preparative work for isolation of impurities by just evaporating the solvents. It avoids the extraction of other inorganic modifiers.Keywords Ultra high performance liquid chromatography (UHPLC) Á Volatile ion-pair reagents Á Design of experiments (DoE) Á Acetylcholinesterase inhibitor (AChEI) Á Alzheimer's disease (AD)