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A model of cefoperazone tissue penetration: diffusion coefficient and protein binding
1Laboratoire de Biophysique, Faculté de Médecine Xavier-Bichat, Paris, France.
Antimicrobial Agents and Chemotherapy
|February 1, 1992
Summary
The study found that only free cefoperazone drug diffuses, not protein-bound drug. Voltammetry accurately measured drug binding, revealing lower binding percentages than other methods.
Area of Science:
- Pharmacokinetics
- Drug Diffusion
- Analytical Chemistry
Background:
- Understanding drug diffusion is crucial for effective drug delivery.
- Cefoperazone is an antibiotic whose diffusion characteristics require elucidation.
- Protein binding can significantly impact drug distribution and efficacy.
Purpose of the Study:
- To determine the apparent diffusion coefficient of cefoperazone.
- To investigate the influence of protein binding on cefoperazone diffusion.
- To compare drug binding measurements using voltammetry versus ultrafiltration centrifugation.
Main Methods:
- Voltammetry was employed for rapid measurement of cefoperazone protein binding.
- Apparent diffusion coefficients were measured in agar, fibrin, and rat brain tissue.
- Comparison of binding percentages obtained from voltammetry and ultrafiltration centrifugation.
Main Results:
- Apparent diffusion coefficients for cefoperazone were similar in agar and fibrin but lower in rat brain tissue.
- The influence of protein on the apparent diffusion coefficient was found to be negligible.
- Voltammetry indicated a lower percentage of protein binding compared to ultrafiltration centrifugation.
Conclusions:
- The study supports the hypothesis that only the free fraction of cefoperazone diffuses.
- Voltammetry provides a more accurate measure of diffusible drug concentration than ultrafiltration centrifugation.
- Discrepancies in binding measurements may be attributed to the dissociation rate of the protein-drug complex.