Pharmacology The Calcium Channel Blocker

Question: Write an essay on Pharmacology. Answer: Verapamil is an organic compound that is also a calcium channel blocker. It is used as a drug for the treatment of hypertension, cardiac arrhythmia, and angina pectoris. Verapamil has been extensively used as a vasodilator and is easily absorbed by the body after oral administration. On administration of the drug, it undergoes the far-reaching epatic metabolism through portal circulation, leading to a low bioavailability. The chief metabolic pathway of Verapamil involves N-dealkylation and N-demethylation. CYP3A4 is mainly responsible N-demethylation for the Verapamil. Piperine is an alkaloid which inhibits the CYP3A4 in the metabolic pathways. In of the studies it was reported that Piperine was found to inhibit the cytochrome P450 isoenzyme CYP3A4. Thus, it can be said that certain natural bionhancers mostly extracted parts of the plant promotes the bioavailability or biological activities of certain drugs consumed which are therapeutically used. Therefore, the aim of the current re port is to examine the effect of Piperine on the bioavailability of Verapamil (Rezaee et al., 2014). Material and methodology: The following materials and equipment were used as supplied by the manufacturer. All chemicals and reagents used were of analytical grade and any other available grade. Equipment used: Electronic weighing balance, REMI centrifuge, HPLC Assembly, Cyclo Mixer, Digital pH meter, Syringe filter, Incubator, Aspirator, Melting point apparatus (Moghadamnia, 2014). Animal study All study was carried out in healthy Wistar rats weighing between 200-250gm. The animals were procured from the disease-free animal house, Institute of Pharmaceutical Sciences, KUK. Animals were housed (5 per cage) for two weeks for adaptation prior to starting the experiment. The dose of Verapamil was taken as 10 mg/kg, and a dose of Piperine was taken as 15 mg/kg (Feng et al., 2014). As discussed by Volak et al. (2013), each animal were anesthetized with Thiopental Sodium (50mg/kg i.p), and blood samples were collected retro-orbitally and throughout the experiment the body temperature was maintained at 37C in order to prevent hypothermic alteration in the blood circulation. Verapamil and Piperine were orally administered to the rats through gastric intubation on the day of the experiment. Blood samples (0.2 ml) were collected through retro-orbital at 0, 0.5, 1, 2, 4, 6, 8, 12, 24 h after the oral administration of verapamil (Feng et al., 2014). Figure- 1: Pictorial representation of retro-orbital method HPLC The plasma concentrations of verapamil were determined by HPLC assay described as follows. Perfusate samples were thawed at room temperature, centrifuged at 4000 rpm for 5min and supernatants were subjected to HPLC analysis. Though HPLC the mixture which needs to be separated and also analyzed were introduced in a small proportion into a stream of mobile phase through the use of a column. The mobile phase of used here was acetonitrile and the stationary phase was Kromasil KR 100-5C8 column. Pharmacokinetic analysis - As discussed by Kesarwani Gupta (2013), each animals were anaesthetized with Thiopental Sodium (50mg/kg i.p), and blood samples were collected retro-orbitally. During the experiment, the body temperature was maintained at 370.5C to prevent hypothermic alteration of blood circulation. Verapamil and Piperine was orally administered to the rats through gastric intubation on the day of experiment. Blood samples (approximately 0.2 ml) were collected through retro-orbital at 0, 0.5, 1, 2, 4, 6, 8, 12, 24 h after the oral administration of verapamil (Adams et al., 2014). Statistical analysis: Statistical analysis was conducted using one-way ANOVA followed by a posteriori testing with the Dunnett correction. Differences were considered significant at the level of P Result: All the means were presented with their standard deviation. The pharmacokinetic parameters on comparing with one-way ANOVA showed the significant statistical result. The mean plasma concentration-time profiles of verapamil pretreated with Piperin were characterized in Wistar rats. The use of Peperin enhanced the bioavailability of Verapamil (Singh et al., 2013).. Discussion: According to Kesarwani Gupta (2013), the active efflux and the intestinal metabolism of the drug absorbed have been recognized as a key determinant of the bioavailability of various drugs. It was observed that CYP3A4 was available as a major phase 1 drug metabolizing enzyme in the rats. This was present in a high level in the small intestine which is the primary site of the orally absorbed drug Verapamil. The intestinal phase I metabolism and also the active efflux of Verapamil was recognized as the main determinant of the bioavailability of several other drugs. The current study evaluated, the influence of Piperine, which is a natural enhancer, increases theCmaxand AUC of verapamil increased approximately two times in the rabbits pretreated with Piperin, as compared to Verapamil alone (Wang et al., 2013). Conclusion: Verapamil has been extensively used as a vasodilator and is easily absorbed by the body after oral administration. On administration of the drug, it undergoes the far-reaching epatic metabolism through portal circulation, leading to a low bioavailability. Piperine is an alkaloid which inhibits the CYP3A4 in the metabolic pathways. 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