In August 2010, the FDA (CDER) published its draft Guidance for Industry "Residual Drug in Transdermal and Related Drug Delivery Systems".
This Guideline addresses developers and manufacturers of transdermal systems for the delivery of therapeutically active ingredients - including e.g. patches that release drug substances. The document covers all systems by which a drug substance is delivered via the skin or mucosa. Examples include drug substances in patches, gels, foams, films and spray-on films, etc.
Such systems contain considerably more drug substance than the quantity intended for delivery to the patient. The FDA estimates that systems currently marketed may retain 10-95% of the original concentration of the drug substance on the used product following the intended use of the medication. This raises a potential safety issue: some children have died after exposure to residual medication on used products that have not been properly disposed of.
Accordingly, the FDA is calling on the industry to enhance its design and development approach for these product groups, in consideration of Quality by Design (QbD) as described in ICH Q8 (R2). The application of QbD is intended to achieve the continuous improvement of a product throughout its lifecycle.
The objective must be to achieve the least possible amount of residual drug substance following the product's period of use.
This Guideline applies to INDs, NDAs, ANDAs and supplemental sNDAs. To get more information please see the FDA Draft Guideline.
Dr Günter Brendelberger
On behalf of the European Compiance Academy (ECA)