An investigation into the biopharmaceutics classification and a study of the in vitro bioavailability (permeability and solubility) of the antiviral compound enisamium iodide (4-(benzylcarbamoyl)-1-methylpyridinium iodide) were carried out. The solubility of enisamium iodide was determined in four different buffers. Apparent intestinal permeability (Papp) of enisamium iodide was assessed using human colon carcinoma (Caco-2) cells at three concentrations. The solubility of enisamium iodide in four buffer solutions from pH 1.2 to 7.5 is about 60 mg/mL at 25 °C, and ranges from 130 to 150 mg/mL at 37 °C, depending on the pH. Based on these results, enisamium iodide can be classified as highly soluble. Enisamium iodide demonstrated low permeability in Caco-2 experiments in all tested concentrations of 10–100 μM with permeability coefficients between 0.2 × 10−6 cm s−1 and 0.3 × 10−6 cm s−1. These results indicate that enisamium iodide belongs to class III of the Biopharmaceutics Classification System (BCS) due to its high solubility and low permeability. The bioavailability of enisamium iodide needs to be confirmed in animal and human studies.

Aim. In order to determine the role of the biopharmaceutical classifi cation system in the development of new drugs, the concept of bioavailability and bioequivalence has been investigated.Methods and results. Theoretically analysis of application of BCS in pharmaceutical development of solid dosage forms and systems analysis of research, relating to BCS has been studied.Article shows the analysis of the scientifi c researches of BSС and original sources application in the scientifi c bases of world level of SciTech development, a comparative analysis of freeing and absorption operating substances' models, introduction of generic pharmaceutical preparations based on EMA, FDA, USP, WHO regulator documents.Conclusion. Biopharmaceutical classifi cation system is a powerful factor in the development of new and effective generic drugs.

In the article it is presented data on the relevance of drugs from the group of analgesics-antipyretics in the form of fast dissolving solid dosage forms and excipients for its manufacture are described. The advantages of a sachet as a solid dosage form are described. For developing a sachet with anti-inflammatory properties, the features of active pharmaceutical ingredients interrelation and their physicochemical properties, which determine the technology, are shown. The purpose of this work was to select the excipients for improvement the pharmaco-technological and organoleptic characteristics of the sachet. We studied 27 excipients 5 functional groups. The experiment is based on the Latin cube of the second order. Technology was the mixing of components. The obtained mass was tested twice on pharmaco-technological parameters and the characteristics of the solution. Experimental data were subjected to statistical analysis by the method of dispersion analysis. The results were expressed using ranked rows of benefits and bar charts. The results of the study present the effect of excipients from groups of alkaline and acid fractions, dyes, flavors, fillers on the quality of the sachets. The results of the study show that the different tested excipients show the greatest influence on appearance of the mass, bulk density, density after shrinkage, Carr`s index, fluidity, angle of the slope, mass loss in drying, solution appearance, solution smell, solution taste and pH of the solution. Generalized results of dispersion analysis showed that calcium phosphate, citric anhydrous acid, maleic acid, curcumin, lemon-lime flavor and sugar powder improve the pharmacological-technological and organoleptic characteristics of the studied sachet. In the result of the work, the selection of excipients in the development of a sachet is scientifically substantiated. The influence of the exipiences nature on the pharmaco-technological indicators sachets and organoleptic properties was studied. It was selected the excipients for the optimal sachet composition with anti-inflammatory properties.

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...

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