Drugs produce their effects by interacting with receptor targets. In studying drug-receptor interactions throughout the organism, the receptor can be considered relatively fixed, and each drug molecule begins at its site of administration and travels through the body to the receptor on which it acts. Pharmacokinetics (PK) and pharmacodynamics (PD) are the two main branches of pharmacology that deal with both aspects of this process. The complex biochemical interactions that occur between the body's natural processes and drugs are analyzed and described through PK and PD, both of which play a key role in determining the safety and efficacy of drugs.
PK is the study of the concentration of a drug in the body over a period of time and it includes the processes by which the drug is absorbed, distributed, metabolized and excreted (ADME), i.e. the body's action on the drug. The importance and utility of PK studies in early drug development has long been recognized for addressing different questions, including:
With the exception of drugs administered intravenously, only a small fraction of the drug dose is absorbed and pharmacologically active, and PK is used to quantify the rate and extent of drug exposure.
Probing the correlation of PK values with the toxicity observed during the trial to help manage different toxicity profiles that may be associated with maximum drug concentration and area under the curve to determine different dosing regimens.
For orally administered drugs, food effect studies are important to understand the effect of food on drug absorption and can help in making drug dosing recommendations.
Drug-drug interactions may make a drug less effective, cause unexpected side effects, or increase the effects of a specific drug. Some drug-drug interactions may even be harmful. Drug interactions fall into three broad categories: drug-drug interactions, drug-food/beverage interactions, and drug-conditions interactions.
PD is the study of the relationship between the concentration of a drug and its biological effect, i.e. the effect of the drug on the body. PD biomarkers are molecular indicators of the effect of a drug on an organism's target and can be used to examine the link between drug regimens, target effects and biological tumor responses. PD places special emphasis on dose-response relationships, both negative and positive. Negative effects include increased probability of cell mutation (also known as oncogenic activity), induction of physiological damage, abnormal chronic disease, adverse reproductive effects and lethality. Therefore, an understanding of drug behavior is absolutely critical in drug development research.
There are two main types of PD biomarkers: (1) predictive biomarkers that constitute any measure related to response/lack of response or toxicity; and (2) mechanism of action biomarkers that reveal insight into the PD effects of a drug.
The effective concentration (EC) is a dose or concentration of a drug that produces a biological response. The concentration-effect relationship is the cornerstone of PD.
The concept of multicellular pharmacodynamics (MCPD) is a dynamic and static relationship between a drug and the multicellular four-dimensional organization of an organism.
PK and PD together influence factors such as dose, drug benefit and side effects. PK/PD studies can explore the effect of the organism on the drug and the effect of the drug on the organism, and provide a more comprehensive and accurate understanding of the pattern of drug effects with dose (or concentration) and time, thus providing a more scientific and theoretical basis for the safety and efficacy of clinical drug use. PK/PD studies provide effective PK/PD studies provide effective theoretical guidance for new drug evaluation, and significantly shorten the cycle time, save resources, and provide accurate and reliable data support.
PK/PD studies cover all stages of development of pharmacologically relevant species.
With the strong expertise and 24h customer service, BOC Sciences provides superior clinical and non-clinical PK/PD analysis to support drug development programs. Our flexible reporting options range from PK/PD modeling to robust, submittable preclinical ADME reports. Contact us today to learn more about how our various PK/PD analysis services can benefit your program.