Design, synthesis and hypolipidemic activity of novel 2-(naphthalen-2-yloxy)propionic acid derivatives as desmethyl fibrate analogs.

A series of 2-(naphthalen-2-yloxy)propionic acid derivatives were prepared. The hypolipidemic activity of the new compounds as well as the intermediate acid 2 was evaluated in the high cholesterol diet (HCD) fed hyperlipidemic rat model. Interestingly, the S-alkylated mercaptotriazole 8b and the 1,3,4-oxadiazole 9 produced striking reduction of serum levels of total cholesterol (TC), triglycerides (TGs) and low-density lipoproteins (LDLs) and elevation of serum high-density lipoproteins (HDLs) being more active than the reference gemfibrozil. In addition, the 1,2,4-triazole 7a, the hydroxypyrazoline 10 and the pyrazolone derivative 11 exhibited good hypolipidemic activity on different lipid parameters.

Use of charge-transfer complexation in the spectrophotometric analysis of certain cephalosporins.

Three simple, rapid and sensitive spectrophotometric procedures were developed for the analysis of cephapirin sodium (1), cefazoline sodium (2), cephalexin monohydrate (3), cefadroxil monohydrate (4), cefotaxime sodium (5), cefoperazone sodium (6) and ceftazidime pentahydrate (7) in pure form as well as in their pharmaceutical formulations. The methods are based on the reaction of these drugs as n-electron donors with the sigma-acceptor iodine, and the pi-acceptors: 2,3-dichloro-5,6-dicyano-p-benzo-quinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ). Depending on the solvent polarity, different coloured charge-transfer complexes and radicals were developed. Different variables and parameters affecting the reactions were studied and optimized. The obtained charge-transfer complexes were measured at 364 nm for iodine (in 1,2-dichloroethane), 460 nm for DDQ (in methanol) and 843 nm for TCNQ (in acetonitrile). Ultraviolet-visible, infrared and (1)H-nuclear magnetic resonance techniques were used to study the formed complexes. Due to the rapid development of colours at ambient temperature, the obtained results were used on thin-layer chromatograms for the detection of the investigated drugs. Beer's plots were obeyed in a general concentration range of 6-50, 40-300 and 4-24 mug ml(-1) with iodine, DDQ and TCNQ, respectively, with correlation coefficients not less than 0.9989. The proposed procedures could be applied successfully to the determination of the investigated drugs in vials, capsules, tablets and suspensions with good recovery; percent ranged from 96.47 (+/-1.14) to 98.72 (+/-1.02) in the iodine method, 96.35 (+/-1.62) to 98.51 (+/-1.30) in the DDQ method, and 95.98 (+/-0.78) to 98.40 (+/-0.87) in the TCNQ method. The association constants and standard free energy changes using Benesi-Hildebrand plots were studied. The binding of cephalosporins to proteins in relation to their molar absorptivities was studied.