Talk your team.

The test certainly has to be done in In laboratory under observation.

Such experiments cannot be done on wild rats, the rats needs to be quarantined in laboratory processed system.

Regards

Dr Fatema Miah

To scale the in vitro concentration of 128 µg/ml for in vivo experiments on mice, several approaches can be utilized:

1. Allometric Scaling: This method involves using body weight or surface area to predict the appropriate dose for mice based on the in vitro concentration. A common formula is:

Dose in-vivo​=Dose in-vitro​×(Body Weight × human​Body / Weightmouse​​)0.75

This scaling accounts for metabolic differences between species and can help adjust the dose accordingly.

2. Pharmacokinetic/pharmacodynamic (PK/PD) Modeling: By developing a PK/PD model that links the in vitro data with expected in vivo outcomes, you can predict the effective dose needed to achieve similar drug concentrations in vivo as observed in vitro. This approach considers factors like absorption, distribution, metabolism, and excretion (ADME) of the drug in mice compared to cell cultures.

3. In Vitro-In Vivo Extrapolation (IVIVE): This technique uses concentration-response data from in vitro studies to estimate the corresponding in vivo doses. The goal is to determine an in vivo concentration that would produce similar pharmacological effects as in vitro. This can involve simulations and adjustments based on known pharmacokinetic parameters.

4. Empirical Testing: If available, conducting preliminary trials with various doses starting from a calculated estimate based on the above methods can help refine the exact dose needed for effective bacterial growth inhibition in vivo.

Combining these approaches allows you to effectively determine a suitable dose for your in vivo experiments that reflects the efficacy observed in your in vitro studies.

Citations:

[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC7070804/

[2] https://www.frontiersin.org/journals/toxicology/articles/10.3389/ftox.2022.885843/full

[3] https://www.allucent.com/resources/blog/what-allometric-scaling-and-how-does-it-support-drug-development

[4] https://pmc.ncbi.nlm.nih.gov/articles/PMC1751780/

[5] https://www.nature.com/articles/srep13545

[6] https://www.criver.com/eureka/its-all-about-dose-how-link-vitro-and-vivo

[7] https://www.researchgate.net/post/How-to-extrapolate-result-from-in-vitro-ug-mL-to-in-vivo

[8] https://ascpt.onlinelibrary.wiley.com/doi/10.1002/psp4.12895

Performing LD50 study for unknown molecule should work, then opt for 3-5 lower dose. Suggested is to go till LD12.5. However, if the drug/molecule is known then you can find the dose in literature that aligns with your route of administration. It is recommended to perform PK and toxicity studies if time permits, to more accurately calculate the administration dose for in vivo. Hope this helps.