Determination of Drug-Like Properties of a Novel Antileishmanial Compound: In vitro Absorption, Distribution, Metabolism, and Excretion Studies

ABSTRACT

In drug discovery research, the compounds should not only to be potent and selective but also must possess acceptable pharmacokinetic properties such as absorption, distribution, metabolism, and excretion (ADME) to increase success rate in clinical studies.

MATERIALS AND METHODS: Experimental protocols were established and validated for stability (in PBS pH7.4, simulated gastric and intestinal fluid), solubility, permeability, distribution coefficient (Log D), plasma protein binding and metabolism by rat liver microsomes by using spectrophotometer or HPLC. Methods were considered valid if the results of the standard compounds matched with reported results or within acceptable range or with proper ranking (high-medium-low).

RESULTS: The compound was found to be stable (>95% remaining) in all stability studies and aqueous solubility was 299.7 +/- 6.42 muM. The parallel artificial membrane permeability assay (PAMPA) indicated its medium permeability (Log Pe = -5.53 +/- 0.01). The distribution coefficients (Log D) in octanol/PBS and cyclohexane/PBS systems were found to be 0.54 and -1.33, respectively. The plasma protein binding study by the equilibrium dialysis method was observed to be 78.82 +/- 0.13% while metabolism by Phase-I enzymes for 1 hour at 37 degrees C revealed that 36.07 +/- 4.15% of the compound remained after metabolism.

CONCLUSION: The methods were found to be very useful for day-to-day ADME studies. All the studies with the antileishmanial compound ascertained that the compound bears optimum pharmacokinetic properties to be used orally as a potential drug for the treatment of leishmaniasis.

The article is published in the Indian Journal of Pharmacology and free to access.