Antacids dosage form are a class of drugs used to chemically bind and neutralize stomach acid. Simethicone is one of the antacids that works as an antiflatulant. In an effort to guarantee the quality of a preparation, a valid analysis method is needed that meets the validation parameters. This study aims to modified of extraction method of the simethicone content of suspension samples using the FTIR method. The methods include simethicone modification of extraction from suspension preparations with toluene solvents and hydrochloric acid (2:5) 3.35. Validation methods include: determination of precision, accuracy, limit of detection (LOD), and limit of quantification (LOQ) at wave number 1261 cm-1 and determination of the content of samples of simethicone suspension. The results showed that linearity parameters with a correlation coefficient of 0.997 in a concentration range of 1000-10,000 ppm, precision with a value of KV <2%, LOD and LOQ, respectively 378.97 and 1250.59 ppm. The results of the determination of simethicone suspension samples indicate that this method met the requirements of the validation parameters.Keywords: Validation, Simethicone, Infrared Spectrophotometry, antacid

Bioanalysis study and its validation are important for the application in natural drug discovery and preparation for natural medicine products with safe drug development approaches. Bioanalysis data for natural products can provide quantitative information on active compounds from natural products for pharmacokinetics, pharmacodynamics, bioavailability, bioequivalence, and toxicokinetics. Bioanalysis validation provides useful guidance for obtaining accurate data on drug discovery, preclinical and clinical testing of natural drug product development, and to ensure the methods used are suitable for application in testing the samples. In general, sample preparation and validation of the bioanalysis method are part of the pharmacokinetic characterization of a chemical compound from the discovery to the development stage of natural material products. Therefore, this paper aims to discuss how to prepare samples and validate bioanalysis for natural products.