Toxicokinetics is known as the process of generating the pharmacokinetic data. This data is generated either in the form of an integral component to be employed in the process of non-clinical toxicology or specifically designed studies for supporting the assessment of the systemic exposure.
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Pharmacokinetics vs Toxicokinetics –
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While the TK studies shares its important parameters (Cmax and AUC) with pre-clinical pharmacokinetic parameters, both the studies have certain degree of distinction between them –
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The toxicokinetic studies are preliminarily aimed at correlating the findings of the toxicity with a corresponding dose exposure levels of an experimental pharmaceutical drug candidate.
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TK studies often utilizes the doses which are beyond their therapeutic relevance. Administration of such higher doses potentially leads to the yielding of distinct kinetic parameters from the Pk data. This pk data might assist in informing the clinician with the accurate dosing consideration and drug safety margins throughout the later drug discovery and development stages. This is inclusive of both the clinical and pre-clinical evaluation.
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How the ADME characterization process influences your toxicokinetic analysis?
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No matter whether the study subject is animal or human, the pharmaceutical drug compound under evaluation undergoes drastic changes in both its location and composition as it passes through the human body. ADME characterization directly impacts the clinical toxicology analysis by impacting their concentration versus time profile. It also affects the non-clinical toxicology profile qualitatively through producing therapeutic effect on the molecular level.
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Absorption –
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Absorption is defined as the process wherein a pharmaceutical drug candidate is being absorbed within the human body. For the GLP toxicology studies, the administration route affects how rapidly the drug is absorbed within the human body as well as its location. Route of administration of the drug formulation affects dissolution rate of the compound, and in turn, its bioavailability.
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Distribution –
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Distribution is defined as a process wherein the drug once surpasses the systemic circulation. In the GLP toxicology studies, distribution can be correlated with the reversible transfer of the molecule of the pharmaceutical drug candidate from the systemic circulation to other body parts.
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Metabolism –
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Metabolism defines how the chemical make-up of the pharmaceutical drug candidate undergoes alteration as it moves across the human body. In Tk studies, it is important to consider the enzymatic activity on the metabolizing pharmaceutical drug candidate. This enzymatic activity is subject to change according to the age, sex, species, tissue type, etc. of the subjects involved in the clinical trials.
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Excretion –
Excretion is defined as the process wherein the pharmaceutical drug candidate is eliminated from the human body. For determining the overall exposure during the course of GLP tox studies, rate of excretion is important to be considered. Slow excretion results in the amplification of the toxic effects produced by the pharmaceutical drug candidate whereas its rapid excretion may lead to a lack of effective drug distribution to the target tissues.
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On a concluding note, it can be inferred that both the pharmacokinetics clinical trials and toxicokinetic studies shares some common parameters. Yet, the purpose of performing these studies are quite different from each other.
