圆上私修 u 国生 Structure and function of skin Factors affecting drug permeation through the skin Semisolid dosage forms Semisolid dosage forms and transdermal systems .Categories of semisolid dosage forms .Common constituents of dermatological preparations School of pharmacy General methods of preparation In vitro evaluation of TDDS Chen Jian 2012.4 Transdermal drug delivery system(patch) chenjian @situ.edu.cn Design and manufacture of TDDS In vitro evaluation of TDDS 国ft线Structure and function of skin 国生 Stratum corneum ©Structure of skin Brick and mortar model:the keratinized corneocytes act as protein "bricks"embedded in a lipid "mortar" ·Epidermis(表皮) ·Stratum corneum/homy laver(角质层) ·Viable epidermis(活性表皮) ·Dermis(真皮) Network of capillaries ·Subcutaneous tissue(皮下组织) ·Skin appendages 国生一 国生 Factors affecting drug permeation through the skin The process of percutaneous absorption Biological factors affecting percutaneous absorption ·Water content in skin Dissolution of drug in vehicle Diffusion through vehicle Anatomical site variations Transepidermal/transfollicular route ·Integrity of the skin Partitioning into viable epidermis Surface temperature Diffusion through viable epidermis and dermis ·Skin metabolism ·Capillary uptake ·Systemic dilution .Individual difference(age,gender,race et al.) 11 Semisolid dosage forms and transdermal systems School of pharmacy Chen Jian 2012.4 chenjian@sjtu.edu.cn Shanghai Jiao Tong University Structure and function of skin Factors affecting drug permeation through the skin Semisolid dosage forms • Categories of semisolid dosage forms • Common constituents of dermatological preparations • General methods of preparation • In vitro evaluation of TDDS Transdermal drug delivery system (patch) • Design and manufacture of TDDS • In vitro evaluation of TDDS Shanghai Jiao Tong University Structure and function of skin Structure of skin • Epidermis (表皮) • Stratum corneum/horny layer（角质层） • Viable epidermis（活性表皮） • Dermis (真皮) • Network of capillaries • Subcutaneous tissue (皮下组织) • Skin appendages Shanghai Jiao Tong University Stratum corneum Brick and mortar model: the keratinized corneocytes act as protein “bricks” embedded in a lipid “mortar” . Shanghai Jiao Tong University The process of percutaneous absorption • Dissolution of drug in vehicle • Diffusion through vehicle • Transepidermal/transfollicular route • Partitioning into viable epidermis • Diffusion through viable epidermis and dermis • Capillary uptake • Systemic dilution Shanghai Jiao Tong University Factors affecting drug permeation through the skin Biological factors affecting percutaneous absorption • Water content in skin • Anatomical site variations • Integrity of the skin • Surface temperature • Skin metabolism • Individual difference (age, gender, race et al.)