Predicting in vivo absorption of chloramphenicol in frogs using in vitro percutaneous absorption data

Llewelyn, Victoria K., Berger, Lee, and Glass, Beverley D. (2021) Predicting in vivo absorption of chloramphenicol in frogs using in vitro percutaneous absorption data. BMC Veterinary Research, 17 (1). 57.

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Background: Infectious disease, particularly the fungal disease chytridiomycosis (caused by Batrachochytrium dendrobatidis), is a primary cause of amphibian declines and extinctions worldwide. The transdermal route, although offering a simple option for drug administration in frogs, is complicated by the lack of knowledge regarding percutaneous absorption kinetics. This study builds on our previous studies in frogs, to formulate and predict the percutaneous absorption of a drug for the treatment of infectious disease in frogs. Chloramphenicol, a drug with reported efficacy in the treatment of infectious disease including Batrachochytrium dendrobatidis, was formulated with 20% v/v propylene glycol and applied to the ventral pelvis of Rhinella marina for up to 6 h. Serum samples were taken during and up to 18 h following exposure, quantified for chloramphenicol content, and pharmacokinetic parameters were estimated using non-compartmental analysis.

Results: Serum levels of chloramphenicol reached the minimum inhibitory concentration (MIC; 12.5 μg.mL− 1) for Batrachochytrium dendrobatidis within 90–120 min of exposure commencing, and remained above the MIC for the remaining exposure time. Cmax (17.09 ± 2.81 μg.mL− 1) was reached at 2 h, while elimination was long (t1/2 = 18.68 h).

Conclusions: The model, based on in vitro data and adjusted for formulation components and in vivo data, was effective in predicting chloramphenicol flux to ensure the MIC for Batrachochytrium dendrobatidis was reached, with serum levels being well above the MICs for other common bacterial pathogens in frogs. Chloramphenicol’s extended elimination means that a 6-h bath may be adequate to maintain serum levels for up to 24 h. We suggest trialling a reduction of the currently-recommended continuous (23 h/day for 21–35 days) chloramphenicol bathing for chytrid infection with this formulation.

Item ID: 66855
Item Type: Article (Research - C1)
ISSN: 1746-6148
Keywords: Chytridiomycosis, Disease, Frog, Skin absorption, Transdermal, Treatment
Copyright Information: © 2021, The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.
Funders: James Cook University (JCU)
Date Deposited: 30 Mar 2022 03:58
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