ABSTRAK Disolusi merupakan faktor penting dalam pelepasan dan pengembangan sediaan obat. Selain sifat fisika kimia obat, formulasi, dan fabrikasi sediaan; kondisi uji disolusi juga mempengaruhi profil disolusi termasuk jenis medium dan model alat uji. Tujuan penelitian ini adalah untuk mengetahui pengaruh medium disolusi dan penggunaan sinker terhadap profil disolusi tablet floating aspirin. Tablet dibuat dengan metode cetak langsung dengan bahan tambahan Methocel K4M CR, NaHCO3, Ethocel, Aerosil, dan dikalsium fosfat anhidrat. Tablet diuji disolusi menggunakan alat disolusi USP apparatus 2 dengan pengaduk dayung. Medium disolusi yang digunakan yaitu simulated gastric fluid (SGF) tanpa pepsin pH 1,2 dan HCl 0,1 N. Uji disolusi dengan SGF tanpa pepsin pH 1,2 dilakukan dengan dan tanpa sinker. Suhu percobaan 37 ± 0,5 °C dan kecepatan pengadukan 60 rpm. Cairan sampel diambil pada menit ke-15, 30, 45, 60, 90, 120, 180, 240, 300, 360, 420, dan 480. Serapan sampel diukur dengan spektrofotometer UV pada λ 280 nm. Hasil uji disolusi menunjukkan bahwa perbedaan medium yaitu HCl 0,1 N dan SGF tidak mempengaruhi DE480, kinetika, dan mekanisme disolusi tablet floating aspirin. Penggunaan sinker pada medium SGF mempengaruhi DE480, kinetika, dan mekanisme disolusi. Kurva disolusi tablet floating aspirin pada medium HCl 0,1 N, SGF dengan dan tanpa sinker mengikuti kinetika orde I dan mekanisme disolusi menurut model Korsmeyer-Peppas, Weibull, Hopfenberg, dan Hixson-Crowell. Model Higuchi juga sesuai untuk profil disolusi tablet floating aspirin dalam medium SGF dengan sinker. Kata kunci: tablet floating aspirin, medium disolusi, sinker, profil disolusi ABSTRACK Dissolution is an important factor in the release and development of drug dosage form. In addition to physical and chemical properties of the drug, formulation, manufacturing process; the conditions of dissolution test also affect the profile of dissolution including the type of medium and test equipment models. The purpose of this study was to determine the influence of the dissolution medium and the use of sinker on dissolution profile of aspirin floating tablet. The tablets were made by direct compression method with Methocel K4M CR, NaHCO3, Ethocel, Aerosil, and dicalcium phosphate anhydrous as excipients. The in vitro dissolution study was determined using USP apparatus 2 (paddle method), 900 mL dissolution medium at 37 ± 0.2 °C and 60 rpm. The dissolution test using HCl 0.1 N and simulated gastric fluid (SGF) pH 1.2 as medium with and without a sinker. Aliquouts of 5 mL was taken out at intervals of 15, 30, 45, 60, 120, 180, 240, 300, 360, 420, and 480 minutes. The samples were analyzed by UV-Vis spectrophotometer at 280 nm. The result indicated that the difference of medium (HCl 0.1 N and SGF pH 1.2) does not affect DE480, kinetics, and mechanism of dissolution. The use of sinker in SGF affects DE480, kinetics, and mechanism of dissolution. The profile of dissolution of aspirin floating tablets in 0.1 N HCl and SGF pH 1.2 (with and without sinker) follow first-order kinetics and mechanism of dissolution according to Korsmeyer-Peppas, Weibull, Hopfenberg, and Hixson-Crowell models. Higuchi model was also suitable for dissolution profile of aspirin floating tablet in the SGF pH 1.2 with sinker. Keywords: floating tablet of aspirin, medium of dissolution, sinker, profile of dissolution