AAPS PharmSciTech

, Volume 19, Issue 4, pp 1567–1573 | Cite as

Application of an Optimized Tape Stripping Method for the Bioequivalence Assessment of Topical Acyclovir Creams

  • Sumalatha Nallagundla
  • Srinivas Patnala
  • Isadore KanferEmail author
Research Article


This study indicates the application of tape stripping (TS) for bioequivalence (BE) assessment of a topical cream product containing 5% acyclovir. A TS method, previously used successfully to assess BE of topical clobetasol propionate and clotrimazole formulations, was used to assess BE of an acyclovir cream (5%) formulation as well as a diluted acyclovir formulation (1.5%) applied to the skin of healthy humans. An appropriate application time was established by conducting a dose duration study using the innovator product, Zovirax® cream. Transepidermal water loss was measured and used to normalize thicknesses between subjects. The area under the curve (AUC) from a plot of amount of acyclovir/strip vs cumulative fraction of stratum corneum (SC) removed was calculated for each application site. BE was assessed using Fieller’s theorem in accordance with FDA’s guidance for assessment of BE of topical corticosteroids. Adco-acyclovir cream (5%) was found to be BE to Zovirax® cream, where the mean test/reference (T/R) ratio of the AUC’s was 0.96 and the bioequivalence interval using a 90% confidence interval was 0.91–1.01 with a statistical power > 95%, whereas the diluted test product fell outside the BE acceptance criteria with T/R ratio of AUC of 0.23 and a 90% CI of 0.20–0.26. This study indicates that the data resulting from the application of this TS procedure has reinforced the potential for its use to assess BE of topical drug products intended for local action, thereby obviating the necessity to undertake clinical trials in patients.


acyclovir cream topical dosage forms local action bioequivalence acceptance criteria tape stripping FDA guidance 



This study was supported by the Biopharmaceutics Research Institute (BRI), Rhodes University, South Africa, and Dr. Prabhakar Kore Basic Sciences Research Center (BSRC), KLE University, Belgaum, India.


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Copyright information

© American Association of Pharmaceutical Scientists 2018

Authors and Affiliations

  • Sumalatha Nallagundla
    • 1
  • Srinivas Patnala
    • 2
  • Isadore Kanfer
    • 2
    • 3
    Email author
  1. 1.Basic Sciences Research CenterKLE UniversityBelgaumIndia
  2. 2.Division of Pharmaceutics, Faculty of PharmacyRhodes UniversityGrahamstownSouth Africa
  3. 3.Leslie Dan Faculty of PharmacyUniversity of TorontoTorontoCanada

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