Circadian Rhythm - is the biological clock controlling rhythms of processes during a twenty-four-hour cycle which is based on endogenous factors. Chronopharmacokinetics - is the study of pharmacokinetic drug parameters as affected by circadian rhythm or diurnal variation. Administration. Dose Dumping - is a term used to describe the achievement of sustained drug concentration by simply increasing the dose size or by accidental fast release of drug from a sustained release dosage Dosage Form - is the gross pharmaceutical form containing the active ingredient(s) (drug(s)] and vehicle substances necessary in formulating a medicament of desired dosage, desired volume and desired application form, ready for administration. Drug Release or Liberation - is the delivery of the active ingredient from a dosage form into solution. The dissolution medium is either a biological fluid or an artificial test fluid (in vitro). Drug release is characterized by the speed. Clearance - is the hypothetical volume of distribution in ml of the unmetabolized drug which is cleared per unit of time (ml/min or ml/h) by any pathway of drug removal (renal, hepatic and other pathways of elimination). Creatinine Clearance - is the delivery of the active ingredient from a dosage form into solution. The dissolution medium is either a biological fluid or an artificial test fluid (in vitro). Drug release is characterized by the speed. Depot Phase - is that portion of a prolonged re lease dosage form which liberates the drug from the dosage form at a slower rate than its unrestricted absorption rate Diffusion Layer - is the viscous layer of concentrated drug solution around a dissolving particle Clinical Pharmacokinetics - is the application of pharmacokinetic principles in the safe and effective treatment of individual patients, and in the optimization of drug therapy. Dose Response Curve - is the graphical presentation of the pharmacological or clinical effectiveness or toxicity (response) versus dose. Drug Specialty or Brand Product - is a drug product, usually of unvarying composition, labeled with a registered trade mark of a single company. Compartment - is an entity which can be described by a definite volume and a concentration of drug contained in that volume Drug - is a chemical compound of synthetic, semisynthetic, natural or biological origin which interacts with human or animal cells. The interactions may be quantified, whereby these resulting actions are intended to prevent, to cure or to reduce ill effects in the human or animal body, or to detect diseasecausing manifestations. Concentration Gradient - is the difference in the concentration in two phases usually separated by a membrane. Dosing Interval - is the difference in the concentration in two phases usually separated by a membrane. Dose Size - is the amount of drug in wg ( = mcg), mg, units or other dimensions to be administered. Dose Dependency - refers to a change of one or more of the pharmacokinetic processes of absorp tion, distribution, metabolism and excretion with increasing dose size. Dosage Regimen or Dose Rate - is the systema tized dosage schedule for therapy, i.e., the proper dose sizes and proper dosing intervals required to produce clinical effectiveness or to maintain a therapeutic concentration in the body Diurnal Variation - is the biological clock control ling rhythms of processes during a twenty-four-hour cycle which is based on external synchronizers (Zeitgeber). Disposition - is the loss of drug from the central compartment due to transfer (distribution) into other compartments and/or elimination and metabolism. Diffusion Layer - is the viscous layer of concentrated drug solution around a dissolving particle.
