Related Experiment Video
Updated: Sep 26, 2026

In Vitro Evaluation of the Potentiating Effects of Plant-Derived Molecules on Conventional Biocides
Published on: May 8, 2026
Assessment of differences in antimicrobial effect determined with two in vitro pharmacodynamic models: impact of
Roger L White1, Charles R Bonapace, Lawrence V Friedrich
1Anti-Infective Research Laboratories, College of Pharmacy, Medical University of South Carolina, Charleston 29425, USA. whiterl@musc.edu
Study Objective:
To measure the influence of different surface area:volume ratios (SA:Vs) on antibiotic penetration and subsequent antibacterial effect.
Design:
In vitro laboratory experiment.
Setting:
Two academic research laboratories.
Intervention:
The two models with effective SA:Vs of 5.34 and 4.80 cm(-1) were evaluated by conducting a time-kill experiment with Pseudomonas aeruginosa ATCC 27853 and ceftazidime.
Measurements And Main Results:
Ceftazidime was administered by constant infusion into the central compartment. Its penetration into the peripheral compartment and bacterial counts were determined over 24 hours, and antibacterial effect was quantified. Antibiotic penetration, calculated using central compartment and peripheral compartment area under the concentration-time curves, and effect, quantified as the relationship between the areas under growth and kill curves, differed between the models. Antibiotic penetration into the peripheral compartment was 53% greater over the first 4 hours of the experiment in the model with the larger SA:V. This was associated with antibacterial effects that were 64% and 38% greater in the 0-4-hour and 0-24-hour time periods, respectively.
Conclusion:
Differences in antibiotic penetration and effect observed between these models are likely explained by differences in SA:V
Related Concept Videos
Pharmacodynamic Models: Overview
Antimicrobial Effectiveness
Pharmacodynamic Models: Direct Effect Model and Indirect Response Model
Impact of Pharmacokinetic–Pharmacodynamic Models: Regulatory Decisions
Pharmacokinetic Models: Comparison and Selection Criterion
Physiological models take a detailed approach by considering specific molecular processes. They can predict drug distribution, metabolism, and elimination changes, providing a comprehensive understanding of how drugs interact with the body.
Pharmacodynamic Models: Linear Concentration–Effect Model

