《第二章药动学》课件

《第二章药动学》PPT课件药动学是研究药物在体内吸收、分布、代谢和排泄的过程及其与给药剂量之间的关系的学科。药动学的定义WhatisPharmacokinetics?Pharmacokineticsisthestudyofhowdrugsareabsorbed,distributed,metabolized,andexcretedbythebody.WhyisitImportant?Understandingpharmacokineticsiscrucialforoptimizingdrugdosingandensuringeffectivetreatmentoutcomes.KeyConceptsPharmacokineticparameters,suchashalf-lifeandclearance,helpquantifydrugbehaviorinthebody.Real-WorldApplicationsPharmacokineticsguidesdoseadjustmentsinspecialpopulations,suchaschildrenandtheelderly.药代动力学血药浓度曲线药代动力学曲线描述了药物在体内浓度随时间的变化情况。半衰期半衰期是药物排除速度的重要参数，衡量药物从体内消失一半所需的时间。生物利用度生物利用度是药物经口给药后被吸收的比例，衡量给药途径对药物的影响。药物吸收过程1PassiveDiffusionMostdrugsareabsorbedpassivelybydiffusingacrosscellmembranesfromhightolowconcentrationgradients.2ActiveTransportSomedrugsaretransportedactivelywiththehelpofcarrierproteins,againstconcentrationgradients.3FacilitatedDiffusionFacilitateddiffusionallowsdrugstopassthroughcellmembraneswiththehelpofspecifictransporterproteins.药物分布过程蛋白结合率蛋白结合率是药物与血浆蛋白结合的程度，影响药物在血浆和组织之间的平衡。血脑屏障血脑屏障是大脑血管与脑细胞之间的屏障，限制了药物进入中枢神经系统。组织结合率药物在体内结合于组织，影响药物的分布范围和持续时间。药物代谢过程1PhaseIMetabolismPhaseImetabolisminvolvesoxidation,reduction,andhydrolysisreactionsthatincreasedrugpolarity.2PhaseIIMetabolismPhaseIImetabolisminvolvesconjugationreactionsthatfurtherincreasedrugpolarityforelimination.3MetabolicEnzymesDrugmetabolismisprimarilycarriedoutbyenzymesintheliver,suchascytochromeP450.药物排泄过程1RenalExcretionThekidneysplayavitalroleinexcretingdrugsandtheirmetabolitesthroughfiltrationandtubularsecretion.2BiliaryExcretionDrugscanalsobeexcretedviathebileintothegastrointestinaltractandeliminatedthroughfeces.3PulmonaryExcretionSomevolatiledrugscanbeexcretedthroughthelungsduringrespiration.药动学参数的计算方法ClearanceTherateatwhichadrugisremovedfromthebody.Calculatedasthedosedividedbytheconcentrationinplasma.VolumeofDistributionTheapparentvolumeinwhichadrugisdistributedinthebody.Calculatedasthedosedividedbytheconcentrationinplasma.AreaUndertheCurve(AUC)T