国生 Dissolution test 国生 Dissolution test 国生一 The rate of drug absorption (especially for poorly selection ®M soluble drugs)is often determined by the rate of in vivo transit ofan doeage form Nemst-Brunner equatioe from the tablet.The rae of dissolution may thus be directly related to the efficiency of the tablet product,as well as to ·Stability of the drug Sinkcods:the cacity for the selected medium to solubiize thed如se is at leastt恤ree times the amount necessary. 国生 Dissolution test 国4线Disspparatu ③Medm selection There are seven apparatuses defined in the USP. Five of them are used for oral dosage forms. Basket +Akhoug purified water is acepable,ts the Paddie prefered medium,because waer has no buffering dissolution rates. capacity. For poodly solubledrugs,the addition of surfactanty ·2-paddle be required to inese the soity. .3.small cup creen at theparanss has 6 baskets wth 0425mm Accurate installation and operating condon Method development for quality control are important to get correct result. .A dissolution method should be eapable of Entrapped gases the dissolution medium can also influence the dissolution rate and different materials and processes. Sesof te uidea particdar tme cause variability However,overdiscrimination can lead to pointand fieedto determine theo Calibrator tablets could be used to ensure unnecessary limitations on manufacturing dissolveddng in solutio laboratories 1414 Shanghai Jiao Tong University Dissolution test The rate of drug absorption (especially for poorly soluble drugs) is often determined by the rate of drug dissolution from the tablet. The rate of dissolution may thus be directly related to the efficiency of the tablet product, as well as to bioavailability differences between formulations. Shanghai Jiao Tong University Dissolution test Medium selection • in vivo transit of an oral dosage form • particular dosage forms • Solubility of the drug • Stability of the drug Shanghai Jiao Tong University Dissolution test Medium selection • Nernst-Brunner equation • Sink conditions : the capacity for the selected medium to solubilize the dose is at least three times the amount necessary. Shanghai Jiao Tong University Dissolution test Medium selection • An aqueous medium, typical pH range for dissolution testing from pH 1 (representing gastric pH) to pH 7.5 (representing intestinal pH), is recommended. • Although purified water is acceptable, it is not the most preferred medium, because water has no buffering capacity. • For poorly soluble drugs, the addition of surfactant may be required to increase the solubility. • In general, non-aqueous systems are discouraged. Shanghai Jiao Tong University Dissolution Apparatuses There are seven apparatuses defined in the USP. Five of them are used for oral dosage forms. Chinese pharmacopoeia specifies that three apparatuses could be used for determining dissolution rates. • 1 - basket • 2 - paddle • 3 - small cup Basket Paddle Shanghai Jiao Tong University Dissolution test Dissolution apparatus has 6 baskets with 0.425mm screen at the bottom. One tablet is placed in each basket, and the basket is positioned in 900ml media, at 37± 0.5℃. The motor is adjusted to turn at a specified speed. Samples of the fluid are withdrawn at a particular time point and filtered to determine the amount of dissolved drug in solution. Shanghai Jiao Tong University Dissolution test Accurate installation and operating conditions are important to get correct result. Entrapped gases in the dissolution medium can also influence the dissolution rate and cause variability. Calibrator tablets could be used to ensure consistent performance across equipment and laboratories Shanghai Jiao Tong University Dissolution test Method development for quality control • A dissolution method should be capable of discriminating products made with different materials and processes. • However, overdiscrimination can lead to unnecessary limitations on manufacturing process ranges, and rejection of products that would otherwise perform well in vivo