533925-39-2Relevant academic research and scientific papers
Stability studies of some glycolamide ester prodrugs of niflumic acid in aqueous buffers and human plasma by HPLC with UV detection
Talath, Sirajunisa,Shirote, Pramod J.,Lough, W. John,Gadad, Andanappa K.
, p. 631 - 639 (2008/02/12)
Glycolamide esters (compounds 1-17) of 2-(3-trifluoromethyl-phenylamino) nicotinic acid (niflumic acid, CAS 4394-00-7) have been synthesized and evaluated as possible prodrugs. In-vitro hydrolysis studies were conducted at selected pH values (1.2, 3.5, 4.8, 7.4 and 7.8) and in human plasma at 37 ± 0.5 °C using HPLC with UV detection. The aqueous (pH 7.4 and 7.8) and enzymatic rates of hydrolysis were substantially affected by the nature of promoieties in this series. The compounds showed good chemical stability in the buffers of low pH values (1.2, 3.5 and 4.8) and appreciable hydrolysis under alkaline conditions and in human plasma. They exhibited long hydrolytic half-lives of 7-46 h in aqueous buffer solutions (pH 7.4 and 7.8) and 14-21 min in human plasma, respectively. It was observed that N,N-disubstituted and cyclic glycolamide derivatives showed 2 fold more hydrolysis in the alkaline pH than monosubstituted derivatives, whereas the piperidino and thiomorpholino derivatives did not undergo chemical hydrolysis. The compounds contain two possible sites for hydrolysis with an increased hydrolytic susceptibility at the terminal aliphatic carbonyl site in aqueous buffers and human plasma solutions. They were found to be cleaved at two hydrolytic carbonyls, namely the nicotinyl (2-5% in enzymatic hydrolysis) and the aliphatic site (7-55% and 70-85% in buffer and plasma hydrolysis, respectively) as revealed by HPLC analysis. The glycolamide ester prodrugs of niflumic acid underwent chemical and enzymatic hydrolysis to release mainly the metabolite 2- (3-trifluoromethyl-phenylamino) nicotinic acid carboxymethyl ester (III) and not the parent drug 2-(3-trifluoromethyl-phenylamino) nicotinic acid. The structure of the metabolite was confirmed by liquid chromatography-mass spectroscopy (LCMS). ECV · Editio Cantor Verlag.
Synthesis, spectral studies and anti-inflammatory activity of glycolamide esters of niflumic acid as potential prodrugs
Gadad, Andanappa K.,Bhat, Shailija,Tegeli, Varsha S.,Redasani, Vivek V.
, p. 817 - 821 (2007/10/03)
In order to reduce the gastric irritation caused by direct contract mechanism of the carboxylic acid group, a series of glycolamide esters of niflumic (CAS 4394-00-7) (1) have been prepared as biolabile prodrugs by reacting appropriate 2-chloroacetamides with niflumic acid. The required 2-chloroacetamides were obtained by the condensation of chloroacetyl chloride and corresponding amine. Their structures were confirmed by UV, IR and 1H NMR spectra. Selected compounds were evaluated for anti-inflammatory activity in carrageenan induced paw oedema in rats at the doses of 45, 90 and 150 mg/kg b.w. Prodrugs showed comparable anti-inflammatory activity (67.1-79.4%) at 150 mg/kg b.w. with respect to niflumic acid (70.3%) at 45 mg/kg b.w., indicating moderate release of niflumic acid in vivo. The highest activity was observed with diethylamine (4) and pyrrolidine (9) derivatives.
