Drug intrinsic

Between these extremes, hepatic clearance is dependent on all three factors Unbound fraction of drug, intrinsic clearance, and hepatic blood flow. The unbound clearance, CLu, equals CL/A. 

Extrinsic moiety Antipsychotic drugs Intrinsic moiety [ ]Hi, M3, and 5-HT2C receptors... 

The anticonvulsant primidone (1035) resembles phenobarbital but lacks the 2-oxo substituent. It was introduced in 1952 and has remained a valuable drug for controlling grand mal and psychomotor epilepsy. As might be expected, primidone is metabolized to yield phenobarbital (1034 X = 0) and C-ethyl-C-phenylmalondiamide (1036), both of which have marked anticonvulsant properties however, primidone does have intrinsic activity and an appropriate mixture of its metabolites has only a fraction of its activity (73MI21303). Primidone may be made in several ways, of which desulfurization by Raney nickel of the 2-thiobarbiturate (1034 X = S) or treatment of the diamide (1036) with formic acid (at 190 °C) seem to be the most satisfactory (54JCS3263). 

Different drugs have different inherent capacities to induce response (intrinsic efficacy). Thus, equal cellular responses can be achieved by different fractional receptor occupancies of these drugs. 

Efficacy is a parameter which describes the strength of a single drug-receptor complex in evoking a response from the cell or tissue. The intrinsic efficacy of a drag is a proportionality constant that defines the power of the drug to induce a response. 

Microbial Resistance to Drugs. Figure 1 MlC-distribution showing the number of isolates of one species with a certain MIC. Some bacterial species are naturally resistant (intrinsic resistance) to drugs because their natural MIC is above the breakpoint. Naturally sensitive isolates as well as naturally resistant ones can acquire resistance and with that increase their MIC (acquired or secondary resistance). 

Two main apoptotic pathways have been identified in mammalian cells the extrinsic pathway that is activated by the binding of ligands to cell-surface death receptors, and the intrinsic pathway that involves the mitochondrial release of cytochrome cP The activation of extrinsic and intrinsic apoptotic pathways promotes the cleavage into the active form of the pro-caspase-8 and pro-caspase-9, respectively, that mainly determine the activation of effector caspase-3. ° The intrinsic pathway is the main apoptotic pathway activated by chemotherapeutic drugs, while the cytotoxic drug-induced activation of the extrinsic pathway is a more controversial issue. ... 

Brogden RN, Goa KL Flumazenil a preliminary review of its benzodiazepine antagonist properties, intrinsic activity and therapeutic use. Drugs 35 448 67, 1988... 

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