Desenvolvimento e validação de um método analítico para determinação de anti-hipertensivos em amostras de estudos de permeação em células caco-2 utilizando cromatografia líquida acoplada à espectrometria de massas

Abstract

The cardiovascular diseases are the main cause of death around the world, and Brazil fallows this same trend. The mortality associated to these diseases rises progressively with the increasing of blood pressure. One of the therapeutic approaches for arterial hypertension is the treatment with drugs, which uses antihypertensive drugsalone or a combination of different classes of these drugs. There are some studies related to the administration of antihypertensive drugs in the form of inclusion complexes with cyclodextrines, in order to model the release kinetics and improve the absorption or increase the stability of the drug. Once used these systems, the drug absorption can be evaluated using in vitro assays by monitoring the value of the fractionof drug dissolved. Therefore, techniques that allow the simultaneous determination of these compounds are required. In this work, a method for the simultaneous determination of different antihypertensive drugs, hydrochlorothiazide, losartan, valsartan and telmisartan, andsome metabolites losartan carboxylic acid, valeryl 4-hydroxy valsartan andtelmisartan 1-O-acylglucuronide, using LC-MS was developed and then validated in samples resulted from Caco-2 permeability assays. These Caco-2 cells were used as models to predict the in vivo absorption in permeability and bioavailability studies. The method has shown high selectivity and sensibility, as confirmed by analysis of theextracted ion chromatograms of telmisartan and the sample matrix, and also by using a high-resolution TOF analyzer. The linear range was the same for all analytes and there was no matrix effect. Precision was smaller than 5.5% for all analytes and the values obtained for accuracy in terms of recovery ranged from 77.4 to 127.2%. The detectionand quantification limits were empirically determined, and the values were 1,0 ìg L-1 and 5,0 ìg L-1, respectively. The methodology was applied to the analysis of telmisartan off and in inclusion complexes formed by telmisartan and â-cyclodextrin at different proportions TLM:âCD: 1:1, 1:2 and 1:3. The results show that the inclusion of the drugincreases their solubility with consequent increased bioavailability.