t生Drying of the wet granules 国生Drying of the wet granules Equilibrium water ©物科中含水量的表达方法 Determination of water content Free water Bound wate ·湿基含水量 ·Loss on drying method Nonbound water ,=配物样中水分的质量 湿物科总质量 100% Karl-Fisher reaction method ·干基含水量 漫物料中水分的质量 x= 湿物料中绝干物料质量×100%6 意水量x利 ④生Drving.of the wet granules 国 Wet granulation Wet granulation ©Oven-tray dryet Advantages of wet granulation Disadvantages of wet granulation Fluid-bed dryer Improved flow properties ®Spray dryer Improved coexpression characteristics Time,sooce,and equipment required wre costly ®Infrared dryer ·Reduction in dusting Microwave dryer Makes hydropobie surtaces more hydrophilie .Improved cn unifoemity processing 生Direct compression Method specially wsefal for drugs tatae affecied by Some gramular chemicals are suitable for moisterih temperatre iolved in wet granula After ad blending,the ponder is com direct compression(free flowing)e.g. agha do mochine.The slugs are Tableting excipients with good flow then broken upandd direct compression of a variety of drugs 1111 Shanghai Jiao Tong University Drying of the wet granules Equilibrium water Free water Bound water Nonbound water Shanghai Jiao Tong University Drying of the wet granules 物料中含水量的表达方法 • 湿基含水量 • 干基含水量  100% 湿物料总质量 湿物料中水分的质量 w x   湿物料中水分的质量 湿物料中绝干物料质量 100% Shanghai Jiao Tong University Drying of the wet granules Determination of water content • Loss on drying method • Karl-Fisher reaction method Shanghai Jiao Tong University Drying of the wet granules Oven-tray dryer Fluid-bed dryer Spray dryer Infrared dryer Microwave dryer Shanghai Jiao Tong University Wet granulation Advantages of wet granulation • Improved flow properties • Improved compression characteristics • Reduction in dusting • Makes hydrophobic surfaces more hydrophilic • Improved content uniformity Shanghai Jiao Tong University Wet granulation Disadvantages of wet granulation • Multiple processing steps add complexity and make validation and control difficult • Time, space, and equipment required are costly • Stability may be a concern for moisture-sensitive or thermolabile drugs • Loss of material during various stages of processing Shanghai Jiao Tong University Dry Granulation Method specially useful for drugs that are affected by moisture or high temperature involved in wet granulation. After mixing and blending, the powder is compressed into large pellets or slugs by passing through a double roller or by compression in a “slugging” machine. The slugs are then broken up and screened. The applied mechanical stresses during processing may lead to phase transformation via the solid-state or melt mechanisms. Shanghai Jiao Tong University Direct compression Some granular chemicals are suitable for direct compression (free flowing) e.g. potassium chloride. Tableting excipients with good flow characteristics and compressibility allow for direct compression of a variety of drugs