AMITY INSTITUTE OF PHARMACY STATISTICAL MOMENTS THEORY & MEAN RESIDENCE TIME(MRT): AMITY INSTITUTE OF PHARMACY STATISTICAL MOMENTS THEORY & MEAN RESIDENCE TIME(MRT) Submitted to: Ms Dipti Srivastava by : Javed siddiqui M.PHARM (2011-2013) Statistical moments theory : Statistical moments theory The Non compartmental approach,based on the Statistical moments theory. It involves collection of experimental data following a single dose of drug. If one considers the time course of drug concentration in plasma as a statistical distribution curve, then MRT = AUMC / AUC Where, MRT=Mean residence time AUC=Area under the zero moment curve AUMC=Area under the 1 st moment curve PowerPoint Presentation: AUMC is obtained from a plot of product of plasma drug concentration and time versus time ‘t’ from zero to infinity. Mathematically, it is expressed by equation: AUC is obtained from a plot of plasma drug concentration versus time from zero to infinity. Mathematically, it is expressed by equation: PowerPoint Presentation: Practically, the AUMC and AUC can be calculated from the respective graphs by the Trapezoidal rule. PowerPoint Presentation: MEAN RESIDENCE TIME MRT is defined as the average amount of time spent by the drug in the body before being eliminated. In this sense,it is the statstical moment analogy of half- life. In effect,MRT represents the time for 63.2% of the intravenous bolus dose to be eliminated.the values will always be greater when the drug is adminstred in a fashion other than I.V.bolus. PowerPoint Presentation: APPLICATIONS It is widely used to estimate the important pharmacokinetic parameters like bioavailibility,clearence & apparent volume of distribution. The method is also useful in determining half life, rate of absorption and first-order absorption rate constant of the drug. PowerPoint Presentation: Advantages Ease of derivation of pharmacokinetic parameters by simple algebraic equations. The same mathematical treatment can be applied to almost any drug or metabolite, they follow first-order kinetics A detailed description of drug disposition characterstic is not required. PowerPoint Presentation: Disadvantages It provides limited information regarding the plasma drug concentration-time profile or it deals with averages. This method does not adequately treat non-linear cases. REFERENCES: REFERENCES Brahmankar D.M;Jaiswal Sunil.B; “Biopharmaceutics and Pharmacokinetics -A Treatise, second edition 2009;vallabh prakashan; page no.254-255.