09 HIGH ON LIFE

Protein Drug Targets Proteins or other biomolecules like DNA,RNA, heparin and peptides to which the drug binds and which are responsible for the therapeutic efficacy of  the drug. Types of protein  targets  :- enzymes receptors ion binding channels Transporters Receptors :-  They are located on both the cell surface and within the cell where medicine produce their beneficial effects in various diseases states. Receptors are typically envisaged as cell surface recognition sites for endogenous hormones, neurotransmitters and neuromodulators. There are 4 types: - Ligand gated receptor Enzyme linked receptor G-protein coupled receptor Intracellular receptor Drug interacts with receptor by means of chemical forces or bonds:- Covalent Electrostatic Lipophillic Hydrogen Agonist : - An agent which activates a receptor to produce an effect similar to that of the physiological signal molecule Antagonist :-  An agent which prevents the action of an agonist on a receptor or the subsequent response

 The knowledge about kinetics helps us to modify the dosing parameters pertaining to patient's specific needs. In the last post we saw the how clearance parameter was derived using various factors , here we'll see the rest of  parameter Clearance Clearance is the volume of fluid presented to the eliminating organ that is effectively cleared of drug per unit time DRUG ELIMINATION  is defined as the sum total of  metabolic inactivition and excretion. k = Rate of elimination / Amount in the reservoir    = Cl . C / A    = Cl . C / V.C Fractional rate of elimination (k) = Cl/v (aka first order elimination rate constant) fig. 1: Compartment model for distribution and elimination FIRST ORDER KINETICS The rate of elimination is directly proportional to the drug concentration , Cl remains constant  fig.2: As the concentration of the beaker increases the rate of elimination also increases. The water being removed demonstrates the rate of elimination and the water in the beaker refers to