PowerPoint Presentation: Dissolution Testing devices Natural convection non sink methods Forced convection nonsink methods Forced convection sink devices Continuous Flow / Flow through devices Special methods 1968 – Pernarowski et al 1969 – Langenbucher column type flow through method 1969 – Baun and Walker (constant circulation) 1970 – Tingstad and Riegelman 1972 – Flow-through modified column apparatus 1975 – Multichamber continuous flow by Cakiryildiz et al 1980 – Takenaka et al 1984 – deutsche arzneimittel codex (DCA) method PowerPoint Presentation: Continuous Flow or Flow Through devices For slightly soluble drugs they need large volumes of dissolution fluids To maintain sink condition, effectively solves the non-sink problems In special cases need to change pH. They are not employed in US. Principle : Sample is restrained in small volume cell and subjected to stream of dissolution media, Pulsating movement is achieved by piston pump. Small number of parameters need to be considered. Inbuilt filter. No sample position problems. Change pH. Ideal hydrodynamic conditions. Open or closed type system. 2 Dissolution testing devices Advantages : PowerPoint Presentation: Cell: Simple cylindrical columns, either empty or filled with glass beads or glass wool, or shaped as separatory funnel, exponential horn shape, spherical, rectangular. Types of systems: Open type - Fresh fluids enter in to the system continuously. Closed type - Dissolution fluid is recycled through the sample cells. 3 Dissolution testing devices Open Closed PowerPoint Presentation: 4 PowerPoint Presentation: 1968 – Pernarowski et al Round bottomed flask with three necks, stainless steal basket Basket is with 10# mesh, stirrer Necks of flask are 33mm, 22mm(2) Fluid flow is 70 ml/min The process can be automated. 5 Dissolution testing devices PowerPoint Presentation: 1969 – Langenbucher column type flow through method Vertically mounted column The dissolution media is pumped through pump p 1 , laminar flow is ensured. Dosage form is placed on the screen that permits fresh dissolution fluid. The filters at the top remove the any disintegrated particles(particulate matter) that would interfere with the analysis. The dissolution fluid is preheated to 37° before entering the cell. The drug specific resistance due to less no of carriers in the git or other reasons can be simulated by recirculation a part of effluents through pump p 2 Lag time between dissolution of drug and removal of solute from system is because of cell and outlet tubing 6 Dissolution testing devices PowerPoint Presentation: 1970 – Baun and Walker (constant circulation apparatus) The dissolution cell(glass) and the reservoir of dissolution media are in Water bath to maintain temperature Continuous duty oscillating pumps ensure pulsating moment and constant flow It uses 100# mesh lower screen in dissolution cell 70±2ml/min is maintained. 7 Dissolution testing devices PowerPoint Presentation: 1970 – Tingstad and Riegelman 8 Dissolution testing devices It consists of cylindrical glass dissolution cell 6.1 cm long, 1.9 cm in diameter Constructed from two small volume glass filter funnel Air trap prevents the air bubbles from distorting analytical reading. Filter membrane of sufficient retentive characteristics, prevent their exit. lower filter, dissolution cell, lower part of upper filter piece, air trap are submerged In water bath to maintain temperature Air trap is open when the pump is turned on, is closed to the analyzer when the liquid level is above the outlet tube. PowerPoint Presentation: 1972 – Flow Through Modified Column Apparatus 9 Dissolution testing devices 4 liter capacity dissolution cell, 37ºc±1ºc. Variable speed of 7 – 150 ml/min rate of flow. Direction of flow of fluid is such that the dissolved particles do not fall through screen. Filter holder employing 14M size nylon filter, Teflon faced stainless steel support screen with a sealing gasket rests on filter holder. Commercially ultra filtration cells (13-25 mm filters are available. Effluents are collected and analyzed continually. PowerPoint Presentation: 1975 – Multi chamber continuous flow cakiryildiz et al 10 Dissolution testing devices It consists of 6 channel peristaltic pump, Thermostated water bath, magnetic stirring plates, analyzer with automated cell changer, Dosage form is inserted from the top of the cells. Less fluids are used so that, Its concentration is maintained 10 – 15% of saturation solubility Flow rates are For powder formulations 8.0±0.2 ml/min, For capsules 16 ± 0.5 ml/min, For tablets 33 ± 1.0 ml/min.