Evaluation of Isolated Vascular Response to 5HT1A, 5HT1B1D & 5HT2A Receptors Agonist & Antagonist in Chronic Endotoxemic Rats

The main vascular feature in endotoxemia is impaired contractile responses to vasoactive agents. We study the aortic response to 5HT11 A, 5HT1B1D and 5HT2A receptors agonist and antagonist in chronic endotoxemic rats. Intraperitoneal injection of 1 mg/kg lipopolysaccharide for 5 days induced chronic endotoxemia. Control rats received intraperitoneal injection of 1 ml/kg saline for 5 days. Rats divided into 3 groups. In first, DOI2 hydrochloride used as an agonist and sarpogrelate hydrochloride as an antagonist of 5HT2A receptor. In second, (R)-(+)-8-OH-DPAT3 and WAY1001354 used as an agonist and antagonist of 5HT1A receptor respectively. In third, Zolmitriptan used as an agonist and GR127935 hydrochloride as an antagonist of 5HT1B1D receptor. Aorta Isolated for organ bath study. Real time-PCR5 and histopathological study examined receptors gene expression and protein localization. Cumulative 8-OH-DPAT caused relaxation in control aorta (EC506 7.79±21.35 and 8.53±10.74 with and without antagonist), which was enhanced in endotoxemia (EC50 6.35±8.48 and very wide±17.38 with and without antagonist). Cumulative zolmitriptan caused relaxation in control aorta (EC50 very wide±8.65 and 8.38±8.44 with and without antagonist), which was enhanced in endotoxemia (EC50 very wide±9.53 and 8.37±13.49 with and without antagonist). DOI hydrochloride contracted the control aorta (EC50 6.51±7.14 and 5.98±1.65 with and without antagonist), which was converted to relaxation in endotoxemic group (EC50 infinity±80.43 and 7.37±20.28 with and without antagonist). PCR studies revealed enhanced 5HT1A receptor and diminished 5HT1B1D and 5HT2A receptor genes expression, while histopathological studies showed inflamed, damaged endothelium in endotoxemic aorta. Our data supports enhanced vasodilation and impaired vasoconstriction during endotoxemia.

DEVELOPMENT AND VALIDATION OF RP-HPLC-PDA METHOD FOR THE ESTIMATION OF SARPOGRELATE HYDROCHLORIDE IN BULK AND DOSAGE FORMS

A simple and precise RP-HPLC method has been developed and validated for the estimation of sarpogrelate hydrochloride, an anti-platelet drug in bulk and pharmaceutical dosage forms. Sarpogrelate is an antagonist at 5HT2A and 5HT2B receptors which blocks serotonin induced platelet aggregation and has application in the treatment of diseases including diabetes mellitus, Raynaud’s disease, angina pectoris and atherosclerosis. Chromatography was carried out on a Phenomenex C18 (250 x 4.6mm, 5μm) column with a mobile phase of 10mM ammonium acetate and acetonitrile (45:55% v/v). The flow rate was 1.2mL/min. The detection wavelength was carried out at 220nm. The retention time is 3.356 minutes for sarpogrelate hydrochloride. The linearity was found in the range of 10-50 μg/ml (R = 0.999) and % RSD is less than 2%. The mean recoveries obtained for sarpogrelate hydrochloride were in the range of 98.73-100.67%. The method is validated as per ICH guidelines and can be applied for the estimation of percentage purity in Sarpogrelate hydrochloride for quality control analysis in bulk and its dosage forms.