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Stratum Corneum Sampling to Assess Bioequivalence between Topical Acyclovir Products
A Pensado1, W S Chiu1, S F Cordery1
1Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
Pharmaceutical Research
|November 16, 2019
Summary
Stratum corneum (SC) tape-stripping effectively assesses topical acyclovir bioequivalence and local skin bioavailability. This method quantifies drug delivery into the skin for site-of-action concentration determination.
Area of Science:
- Dermatopharmacology
- Drug delivery systems
- Bioavailability assessment
Background:
- Topical drug delivery requires robust methods to assess bioequivalence.
- Stratum corneum (SC) sampling offers a non-invasive approach to evaluate drug penetration.
- Understanding local skin bioavailability is crucial for topical formulations.
Purpose of the Study:
- To evaluate stratum corneum (SC) tape-stripping for assessing topical acyclovir bioequivalence.
- To explore alternative metrics for local skin bioavailability using SC sampling.
- To determine the value of SC sampling in topical drug product development.
Main Methods:
- Two studies involved three acyclovir creams and 10 subjects each.
- Drug amounts in the SC were measured post-application and clearance.
- Tape-stripping data were analyzed to deduce acyclovir flux and estimate skin concentration.
Main Results:
- SC sampling identified product similarities and differences, aligning with other bioequivalence measures.
- Tape-stripping data allowed calculation of acyclovir flux into viable skin.
- Estimated drug concentrations in the skin compartment were determined.
Conclusions:
- SC sampling provides objective in vivo comparison of topical product performance.
- This method accurately assesses active drug delivery into skin tissue.
- SC sampling enables determination of local drug concentrations at the site of action.
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