A set of piperonylic acid derived hydrazones with variable isatin moieties was synthesized and evaluated for their inhibitory activity against the enzymes acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and monoamine oxidases A and B (MAO‐A/B). The results of in vitro studies revealed IC50 values in the micromolar range, with the majority of the compounds showing selectivity for the MAO‐B isoform. N‐[2‐Oxo‐1‐(prop‐2‐ynyl)indolin‐3‐ylidene]benzo[d][1,3]dioxole‐5‐carbohydrazide (3) was identified as a lead AChE inhibitor with IC50=0.052±0.006 μm. N‐[(3E)‐5‐chloro‐2‐oxo‐2,3‐dihydro‐1H‐indol‐3‐ylidene]‐2H‐1,3‐benzodioxole‐5‐carbohydrazide (2) was the lead MAO‐B inhibitor with IC50=0.034±0.007 μm, and showed 50 times greater selectivity for MAO‐B over MAO‐A. The kinetic studies revealed that compounds 2 and 3 displayed competitive and reversible inhibition of AChE and MAO‐B, respectively. The molecular docking studies revealed the significance of hydrophobic interactions in the active site pocket of the enzymes under investigation. Further optimization studies might lead to the development of potential neurotherapeutic agents.

A simple, accurate, precise, economical method was developed for the simultaneous estimation of the Ebastine and Montelukast in tablet dosage form by the RP-HPLC method. The chromatogram was run through Kromosil (250mm x 4.6 mm, 5m.) The mobile phase containing potassium dihydrogen phosphate buffer and Acetonitrile was taken in the ratio 60:40 was pumped through the column at a flow rate of 1ml/min. The pH was adjusted to 4.8 with Orthophosphoric acid. A buffer used in this method was potassium dihydrogen phosphate solution. The temperature was maintained at 30°C. The optimized wavelength for Ebastine and Montelukast was 244nm. The retention time of Ebastine and Montelukast were found to be 2.447 min and 3.436 min respectively. With the optimized chromatographic conditions, the drug was linear in the concentration range of 0 -150 μg/ ml. The correlation coefficient was found to be 0.999. The average percentage assay in the formulation was found to be 99.05% and 99.20% for Ebastine and Montelukast respectively. % Recovery for Ebastine and Montelukast was found to be 99.93% and 99.69% respectively. %RSD for repeatability was found to be 0.2 respectively. LOD, LOQ values are obtained from regression equations of Ebastine and Montelukast were 0.11ppm, 0.33ppm and 0.14ppm, 0.43ppm respectively. Regression equation of Ebastine is y = 19263x+1149, and y = 19946x+1095 of Montelukast. Hence the suggested RP-HPLC method can be used for routine analysis of Ebastine and Montelukast in API and Pharmaceutical dosage form.