Topical Dermatologic Dosage Forms and Vehicle Properties: Issues and Opportunities. Jonathan Wilkin, M.D. Director, Division of Dermatologic and Dental Drug Products, FDA. Background I. If it’s dry, wet it. If it’s wet, dry it. Paleodermatologic aphorism. Background II.
Topical Dermatologic Dosage Forms and Vehicle Properties: Issues and Opportunities
Jonathan Wilkin, M.D.
Director, Division of Dermatologic and
Dental Drug Products, FDA
If it’s dry, wet it.
If it’s wet, dry it.
Originally, no “active” ingredient.
Therapeutic choice based on physical and sensory properties.
In the 1800s
Powder (crystals) for bath solution
Bath oils (including bath tars)
Solutions or suspensions for wet dressings and soaks
Shake lotions - “shake” to disperse powders
Creamy-type lotions - (w/o and o/w)
Suspensions (shake lotions)
FDA and USP dosage forms insufficiently defined
Manufacturers produce dosage form intergrades, e.g., between creams and lotions that resist classification
Creation of mutually exclusive definitions for dosage forms and consistent terminology
Summary of relevant vehicle properties in the Description section of product labeling
Provide clinically important information to health care providers choosing among topical dermatologic products
Viscosity - could be an ordinal classification and nonlinear
Spreadability - spread value in mm2 in 10 minutes
Wash and rub resistance
Skin smoothness - time curve
Usual appearance of product, incl. color
Odor of product
Permanence on skin surface - residue at 10 minutes
Moisturization - TEWL time curve
Volatilization - time curve
Salka, Barry A.
well-defined dosage forms
description of relevant vehicle properties
Innovators - more specific description of product may reduce generic competition
Generics - better defined target leads to greater sameness of generic product
Health care providers - better choice among products
Patients - product acceptability improves compliance leading to better outcomes
1. Definitions and Classification of Topical Dermatologic Dosage Forms
Need industry, academia, professional scientific societies, USP and FDA consensus
2. Development of Consistent Methodology and Terminology to Describe Relevant Vehicle Properties (for Description Section of Labeling)
Industry may already have the methods and terminology. Industry must decide if this is desirable. If so, they must be leaders in this effort.