Related Experiment Video
Updated: Oct 16, 2025
09:29
Early Viral Entry Assays for the Identification and Evaluation of Antiviral Compounds
Published on: October 29, 2015
30.4K
Comparative in vitro release testing (IVRT) of acyclovir products.
Katrin I Tiffner1, Isadore Kanfer2, Thomas Augustin1
1HEALTH - Institute for Biomedicine and Health Sciences, Joanneum Research Forschungsgesellschaft m.b.H, Neue Stiftingtalstrasse 2, 8010 Graz, Austria.
International Journal of Pharmaceutics
|October 16, 2021
Summary
An in vitro release test (IVRT) effectively differentiated acyclovir cream products, identifying a suitable negative control for bioequivalence studies. This method shows promise for ensuring drug product quality and performance.
Area of Science:
- Pharmaceutical Sciences
- Dermatology
- Drug Delivery Systems
Background:
- Topical acyclovir formulations are crucial for treating viral infections.
- Ensuring bioequivalence (BE) between generic and reference products is essential for therapeutic efficacy.
- In vitro release testing (IVRT) is a potential tool to predict in vivo performance.
Purpose of the Study:
- To assess the ability of an in vitro release test (IVRT) to differentiate release rates of acyclovir cream products.
- To identify a test product with inequivalent drug release for use as a negative control in bioequivalence (BE) studies.
- To evaluate the sensitivity of IVRT in detecting clinically relevant differences between topical formulations.
Main Methods:
- Comparison of drug release rates from five acyclovir cream products and one ointment against a reference product (Zovirax cream, USA) using IVRT.
- Selection of a test product exhibiting the greatest release rate difference from the reference product.
- Validation of the IVRT method for its ability to discriminate between products.
Main Results:
- The reference product demonstrated equivalent drug release rates when tested against itself.
- All six test products failed to show equivalent drug release rates compared to the reference product.
- Aciclovir 1A pharma cream was identified as a suitable negative control due to its significantly different release rate.
Conclusions:
- IVRT is a sensitive method capable of discriminating clinically relevant differences in drug release between topical acyclovir products.
- An appropriately validated IVRT can support the demonstration of bioequivalence by confirming statistical equivalence in drug release.
- Utilizing IVRT can mitigate the risk of in vivo performance issues arising from undetected product differences.
Related Concept Videos
01:13In Vitro Drug Dissolution: Compendial Testing Models I
13
Compendial dissolution methods are standardized procedures defined by pharmacopeias to evaluate the rate at which a drug dissolves in a specific medium. These methods ensure batch-to-batch consistency, enable quality control, and support the prediction of drug bioavailability. They are critical for both immediate and modified-release drug products.The apparatuses used for dissolution testing differ in their design and mechanical function, but all aim to simulate the physiological environment of...
13
01:10In Vitro Drug Release Testing: Overview, Development and Validation
32
In vitro dissolution and drug release tests assess how quickly and how much of a drug is released from its dosage form into an aqueous medium under standardized laboratory conditions. These tests are essential tools in pharmaceutical development and quality assurance, offering insight into the drug's performance before clinical use.During formulation development, dissolution testing identifies incomplete or inconsistent drug release issues. It also supports decisions on selecting the optimal...
32
01:09In Vitro Drug Dissolution: Compendial Testing Models II
18
Various dissolution methods are utilized to assess a drug’s dissolution rate, including the flow-through cell, paddle-over-disk, cylinder, and reciprocating disk methods.The flow-through cell apparatus (USP (United States Pharmacopeia) method 4) comprises a reservoir for the dissolution medium and a pump that propels the medium through the cell containing the test sample. This method is crucial for assessing modified-release dosage forms with minimally soluble active ingredients,...
18
01:20Drug Product Performance: In Vitro–In Vivo Correlation
22
In pharmaceutical development, it's crucial to establish a predictive in vitro–in vivo correlation (IVIVC) for two or more formulations to gain a comprehensive understanding of release properties. IVIVC reduces the need for costly in vivo studies and facilitates the establishment of meaningful dissolution specifications with significant cost savings and decreased regulatory burden. Furthermore, a meaningful IVIVC should predict Cmax and AUC within 20%, aligning with FDA guidance while...
22
01:17In Vitro Drug Dissolution: Alternative Methods
16
Alternative drug dissolution methods include the rotating bottle, intrinsic dissolution test, peristalsis, and the Franz diffusion cell method. The rotating bottle method involves meticulously rotating tightly capped controlled-release beads in a temperature-controlled bath. Periodic decanting of samples allows for residue assay, followed by refilling with fresh medium and testing at various pH levels to emulate the gastrointestinal tract conditions.In contrast, the intrinsic dissolution test...
16
01:13Bioequivalence studies: Biowaivers
23
Body:In certain scenarios, in vitro dissolution tests can replace in vivo bioequivalence studies. This is particularly true when a drug product, though available in varying strengths, maintains proportional similarity in its active and inactive ingredients. In such cases, the need for in vivo bioequivalence studies for lower strength variants may be waived, provided dissolution tests and in vivo studies on the highest strength yield satisfactory results.Bioequivalence can be indicated through...
23