The biopharmaceutical studies of Valavir film-coated tablets, 0.5 g

Abstract

The biopharmaceutical studies of 0.5 g, with Bioequivalence and bioavailability studies of drugs allow to conduct a rational, selective, comprehensive and efficient pharmacotherapy. Comparative biopharmaceutical studies (experiments in vitro / in vivo) complement the scientific basis of evidence-based medicine.Concerning the pharmaceutical technology of solid dosage forms the biopharmaceutical studies confirm the expedience of selecting excipients and film coating to improve qualitative organoleptic characteristics (appearance, corrected taste, moisture resistance) and pharmacotechnological parameters for convenient use and storage of a drug [1, 3,5].The bioequivalence study is a knowledge-based process requiring specific clinical trials and testing of multiple samples of drugs by highly sensitive methods (chromatography-mass spectrometry, tandem mass spectrometry, etc.) with the high cost of studies. Therefore, prestudies in vitro are usually conducted. The conformity of the kinetics of the active substance release of the drugs developed with original drugs may, to a certain degree of probability, predict similar kinetics in the experiment in vivo.Valaciclovir is a new antiviral drug (ester L-valine hydrochloric salt of acyclovir), which is rapidly and almost completely converted to acyclovir in the human body under the action of valaciclovir hydrolase enzyme. Compared to acyclovir [4], the benefits of valaciclovir include better solubility and bioavailability [6].The half-life of acyclovir after administration of valaciclovir is about 3 hours. The high concentration in the blood plasma created by higher bioavailability of valaciclovir allows reducing the dosage regimen by 1.5 times, and it significantly improves efficiency and safety of the drug.The aim of this study was to conduct the biopharmaceutical studies of Valavir film-coated tablets, 0.5 g, with valaciclovir hydrochloride. Materials and MethodsThe biopharmaceutical studies were conducted in vitro; the dissolution profiles of Valavir film-coated tablets, 0.5 g, and the reference drug Valtrex (film-coated tablets, 500 mg, manufactured by GlaxoSmithKline Pharmaceuticals S.A., Poland) were compared by the method for Dissolution Kinetics developed by us. Dissolution profiles were studied in two media with pH 1.2 and 4.5 as recommended by the State Pharmacopeia of Ukraine (SPhU) [2]. Validity of the given method was proven by the results of the previous experimental studies; the range of the method was determined for the media used and the criteria for comparison of the validation data obtained were substantiated [4]. The results of the study are given in Tables 1-4 below. Dissolution profiles are presented in Fig. 1 and 2.Comparative pharmacokinetic studies to assess bioequivalence of Valavir film-coated tablets, 0.5 g, and Valtrex (film-coated tablets, 500 mg, manufactured by GlaxoSmithKline Pharmaceuticals S.A., Poland) were conducted in healthy volunteers using the method based on 90% confidence intervals for the relationship of logarithmically trans...