图上人生 图上人生 Semisolid dosage forms Semisolid dosage forms ·Ointment bases(USP) ·Ointment bases(USP) ·Absorption bases -May be used as emollients Water-removable bases(cream) -Not easily removed with water washing -O/W emulsions -Are useful as pharmaceutical adjuncts to -Are easily washed form skin incorporate small volumes of aqueous solutions into hydrocarbon bases. -May be diluted with aqueous solutions -For optimum results,the internal aqueous -Through evaporation,the drug is phase should be close to saturated. concentrated in its forming film. -Can absorb serous discharges 国生一 圈生一 Semisolid dosage forms Semisolid dosage forms ·Ointment bases(USP) ·Gels ·Water-soluble bases Gels are semisolid systems in which a liquid -Polyethylene glycol ointment is a water-soluble phase is trapped within an interlocking,three- system that contains fluid,short-chain dimensional polymeric matrix. polyethylene glycols in a crystalline network of high-melting,long-chain polyethylene glycols. -Liquid polyethylene glycols are fully miscible with water,and many drugs that are insoluble in hydrocarbon vehicles readily dissolve in this base. 国赵生 国生 Semisolid dosage forms Semisolid dosage forms ·Pastes ·Rigid foams Pastes are basically ointments into which a Rigid foams are systems in which air or other high percentage of insoluble particulate solids gas is emulsified in a liquid phase to the point have been added-as much or more than 50% of stiffening. by weight in some instances. The solids containing in the pastes can absorb and neutralize certain noxious chemicals before they ever reach the skin. 44 Shanghai Jiao Tong University Semisolid dosage forms • Ointment bases (USP) • Absorption bases – May be used as emollients – Not easily removed with water washing – Are useful as pharmaceutical adjuncts to incorporate small volumes of aqueous solutions into hydrocarbon bases. – For optimum results, the internal aqueous phase should be close to saturated. Shanghai Jiao Tong University Semisolid dosage forms • Ointment bases (USP) • Water-removable bases (cream) – O/W emulsions – Are easily washed form skin – May be diluted with aqueous solutions – Through evaporation, the drug is concentrated in its forming film. – Can absorb serous discharges Shanghai Jiao Tong University Semisolid dosage forms • Ointment bases (USP) • Water-soluble bases – Polyethylene glycol ointment is a water-soluble system that contains fluid, short-chain polyethylene glycols in a crystalline network of high-melting, long-chain polyethylene glycols. – Liquid polyethylene glycols are fully miscible with water, and many drugs that are insoluble in hydrocarbon vehicles readily dissolve in this base. Shanghai Jiao Tong University Semisolid dosage forms • Gels • Gels are semisolid systems in which a liquid phase is trapped within an interlocking, three￾dimensional polymeric matrix. Shanghai Jiao Tong University Semisolid dosage forms • Pastes • Pastes are basically ointments into which a high percentage of insoluble particulate solids have been added—as much or more than 50% by weight in some instances. • The solids containing in the pastes can absorb and neutralize certain noxious chemicals before they ever reach the skin. Shanghai Jiao Tong University Semisolid dosage forms • Rigid foams • Rigid foams are systems in which air or other gas is emulsified in a liquid phase to the point of stiffening