Pharmacokinetic modeling

• Pharmacokinetics Models can be categorized into Empirical/Statistical Model and Compartmental Model.
• Physiological/Blood Flow Model is a simplification of reality to describe, summarize, understand, predict, explain and communicate data to others.
• Pharmacokinetic Models are quantitative models using mathematical terms to concisely describe quantitative relationships.
• The mammillary model is significant because it enables the study of different rate processes.
• The mammillary model enables writing different equations to describe drug concentration changes in each compartment.
• The mammillary model is significant because
• The mammillary model is significant because it shows how many pharmacokinetic constants are necessary to describe the process adequately.
• The mammillary model provides a visual representation of rate processes.
• The mammillary model is significant because it provides a visual representation of rate processes.
• The mammillary model shows how many pharmacokinetic constants are necessary to describe the process adequately.
• Pharmacokinetic Models are used to predict plasma, tissue, and urine drug levels with any dosage regimen.
• Using Pharmacokinetic Models, you can compute for volume of distribution (Vd).
• Pharmacokinetic Models are used to calculate the optimum dosage regimen for each patient individually, usually based on the weight of the patient.
• Pharmacokinetic Models are used to estimate the possible accumulation of drugs and/or metabolites by identifying the plasma concentration of the drug.
• The mammillary model is the most common model used in pharmacokinetics and is useful when little information is known about the tissues.
• In an open two compartment model, the drug can move between the central or plasma compartment (highly perfused) to and from the tissue compartment (peripheral compartment – muscles or fats).
• In a closed model, the administered drug dose is not removed from the body by an excretory mechanism, and the drug will persist in the body forever.
• In an open model, the administered drug dose is removed from the body by an excretory mechanism as the unchanged drug or as metabolite, usually through kidneys and other excretory organs.
• All pharmacokinetic models are open models.
• In an open one compartment model, the drug is both added to and eliminated from a central compartment, which is most commonly used in clinical PK cases.
• Pharmacokinetic Models are used to correlate drug concentrations with pharmacologic or toxicologic activity, with the higher the amount of drug in the body, the higher the intensity of drug effect and sometimes toxicologic effect.
• Pharmacokinetic Models are used to evaluate differences in the rate or extent of availability between formulations (bioequivalence).
• Compartmental models provide a simplistic view of drug disposition in the human body.
• Route of drug administration depends on the site of entry/pathway of drug inside the body.
• Compartmental models are a simple and useful tool, and are the most popular model used to describe pharmacokinetics of a drug.
• The number of parameters in oral administration is higher than in other drug administrations due to the organs and set of tissues that can be reached with the dosage form.
• Empirical/statistical models simply interpolate the data and allow an empirical formula to estimate drug level over time.
• In compartmental models, mixing of drug is rapid and homogenous; “well-stirred”.
• Empirical treatment is a method of giving a first line drug even not knowing the exact reason; a treatment based on observation or experience.
• In compartmental models, a single compartment has the same drug ability and similar drug flow.
• In compartmental models, a compartment is considered a tissue or group of tissues that have a similar blood flow and drug affinity.
• In compartmental models, a compartment is not a real physiologic or anatomic region, but a representation of body organs or tissues.
• Compartmental models provide a simple way of grouping all the tissues into one or more compartments where drugs move to and from the central or plasma compartment.
• Pharmacokinetic Models are used to describe how changes in physiology or disease affect the absorption, distribution, or elimination of the drug.
• Pharmacokinetic Models are used to explain drug interactions, not just drug-drug interaction but also drug-disease interaction and contraindications.
• Invasive methods for obtaining biological specimens for drug concentration measurements require consent, for example, anesthesia.
• Drug concentrations in various tissues are predicted by organ tissue size, blood flow, and experimentally determined drug tissue-blood ratios.
• Measurement of drug concentrations can be done using High Performance Liquid Chromatography (HPLC) or Mass spectrometry.
• Biological specimens for drug concentration measurements can be obtained through invasive methods such as parenteral or surgical interventions in the patient, which include blood, spinal fluid, synovial fluid, and tissue biopsy.
• Noninvasive methods for obtaining biological specimens for drug concentration measurements can be done without parenteral or surgical interventions, such as urine, saliva, feces, and breastmilk.