4,5-dihydro-3(2H)pyridazinones such as CI-914, CI-930 and pimobendan along with tetrahydropyridopyridazine (endralazine) and perhydropyridazinodiazepine (cilazopril) have been used as potent positive inotropes, antihypertensives as well as platelet aggregation inhibitors. Accordingly, the present work involves the synthesis of 24 target compounds; 4,5-dihydro-3(2H)pyridazinones in addition to seven reported intermediates. The chemical structures of the new compounds were assigned by microanalysis, IR, 1H-NMR spectral analysis and some representatives by mass spectrometry. The positive inotropic effect of the final compounds and the intermediates 12a-12d as well as the reported intermediate compound 10 was determined in-vitro on isolated rabbit heart in comparison to digoxin. Data obtained revealed that twelve of the test compounds exhibited higher effective response than digoxin, nine compounds elicited comparable effects to digoxin and eight compounds were less active than digoxin. In addition, four compounds approved marked significant hypotensive effect better than that of the previously reported compound 10. Moreover, two compounds induced complete platelet aggregation inhibition. The last two compounds were also subjected to determination of their LD50 and they showed no signs of toxicity up to the dose level 300 mg/kg (i.p.), while the reported oral LD50 of digoxin is 17.78 mg/kg. Correlation of cardiotonic and hypotensive activities with structures of compounds was tried and pharmacophore models were computed to get useful insight onto the essential structural features required for inhibiting phosphodiesterase-III in the heart muscles and blood vessels.

The present work describes the synthesis and evaluation of some new acetohydrazones, 1,3,4-oxadiazoles and 1,2,4-triazoles of 1,2,4-triazolo[1,5-a]benzimidazole as anti-inflamm atory-analgesic agents. Structure elucidation of these compounds was confirmed by IR, (1)H NMR, and mass spectrometry along with elemental microanalyses. Most compounds exhibited significant anti-inflammatory activity in comparison to indomethacin. Further, some compounds were tested for their analgesic effects where two compounds showed results comparable to indomethacin at 4 h interval. The most active anti-inflammatory and analgesic compounds (4c and 11a) were examined on gastric mucosa and didn't show any gastric ulcerogenic effect compared with the reference indomethacin. Moreover, LD50 of compounds (4c and 11a) were determined in mice; they were found non toxic up to 240 and 300 mg/kg (i.p.). Also, docking simulation of some compounds into COX active sites was studied.

2-Methyl-4(3H)-quinazolines carrying alkyl, cycloalkyl, aralkyl or aryl substituents at N-3 of the quinazoline ring exhibit analgetic, antipyretic and antiinflammatory activities comparable to those of aspirin and phenylbutazone. In our previous work, various 4(3H)-quinazoline derivatives were prepared. The present communication is a continuation of our effort in this field.

The reaction of gliclazide and tolazamide with three selected n-acceptors in acetonitrile -water (9 + 1) at pH 9.0-9.5 was found t o give intensely coloured products. A method based on this reaction is proposed for the determination of trace amounts of both drugs. Quantification was carried out at 445 nm for p-chloranil, 450 nm for p-bromanil and ca. 750 nm for 7,7,8,8-tetracyanoquinodimethane. The molar ratios of the reactants were established and the experimental conditions giving maximum absorption were also studied. The proposed procedures were applied successfully t o the determination of both drugs either in pure samples or in tablets with good accuracy and precision. The results were compared with those obtained by the official USP method.

A simple, rapid, and specific method for determination of adrenaline bitartrate and isoprenaline sulfate was developed. The method is based on the oxidation reaction in aqueous solution of either adrenaline bitartrate or isoprenaline sulfate in the presence of silver oxide to give a red aminochrome measurable at 490 nm. The color is stable for 2 h. Beer's law is valid within a concentration range of 5-80 ng/ mL for each drug. All variables were studied to optimize the reaction conditions. The method is specific for catecholamine drugs having a secondary amine in the side chain. Other catecholamines such as orciprenaline and noradrenaline do not interfere, and no interference was observed in the presence of common pharmaceutical adjuvants. Interference due to sodium metabisulfite and sodium chloride was circumvented. The validity of the method was tested by analyzing adrenaline injections and isoprenaline tablets. Good recoveries were obtained for these preparations. The results were comparable to those obtained by official procedures. The proposed method is also recommended as a stability indicating assay for oxidative degradation of both drugs.