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Presented at the Advisory Committee for Pharmaceutical Science meeting on March 12, 2003 by Lucinda Buhse, Ph.D. Topical Drug Nomenclature. Objective: To establish a scientific basis for a systematic and coherent classification of dosage forms for topical drugs.
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Presented at the Advisory Committee for Pharmaceutical Science meeting on March 12, 2003 by Lucinda Buhse, Ph.D.
Topical Drug Nomenclature Objective: To establish a scientific basis for a systematic and coherent classification of dosage forms for topical drugs. Working Group (ONDC/OGD/DPA): Cindy Buhse, Gil Jong Kang, Saleh Turujman, Mamta Gautam Basak, Chi Wan Chen DPA Laboratory Team: Dick Kolinski, Nick Westenberger, Anna Wokovich, Jack Spencer
Current FDA Definitions • Cream: A semisolid dosage form containing one or more drug substances dissolved or dispersed in a suitable base. • Gel: A semisolid system consisting of either suspensions made up of small inorganic particles or large organic molecules interpenetrated by a liquid. • Lotion: "The term lotion" has been used to categorize many topical suspensions, solutions and emulsions intended for application to the skin. • Ointment: A semisolid preparation intended for external application to the skin or mucous membranes.
What are the distinguishing properties? • Chemical • Base Composition • Physical Properties • Appearance • Feel • Microscopy Physico-chemical • Viscosity • Loss on Drying (LOD) • Specific Gravity • Surface Tension • Water Solubility • Water Absorption • Drying Properties • Thermogravimetric Analysis (TGA)
No Peak Soft Peak Stiff Peak Feel • Greasy vs. non-greasy • Cooling sensation Physical Properties • Appearance • Clear, translucent or opaque • viscous Microscopy - 400x
Creams and Lotions: Multivariate Analysis of Selected Physico-chemical Properties Scores Loadings Lotions Creams Viscosity is potentially a significant variable.
Lotions are pourable (viscosity <30,000 cp at 5 rpm and 25ºC).
Common Characteristics of Most Marketed Gels • Viscosity: low (10,000 - 70,000 cp) • Loss on Drying : high (70-99%) • Solubility : water soluble • Water Absorption : no specific trend • Drying Properties : no specific trend • Thermogravimetric Analysis : fewer transitions • Composition : contains gelling agents (carbomer) • Appearance : clear • Feel : non greasy, cooling • Microscopy : no specific trend
Thermogravimetric Analysis of Selected Products Drug B Drug C Cream Cream Cream Cream Gel Gel Lotion Cream Gel Gel formulations have fewer transitions than the creams.
Classification of Topical Drugs Lotions: • pourable with viscosity <30,000 cp (at 5 rpm and 25ºC) • Loss on Drying > 50% Ointments: • Loss on Drying < 20% • hydrocarbon or polyethylene glycols content > 50% Gels: • contain sufficient gelling agent to form 3D matrix