Answer to Question 1
Efficacy refers to the degree to which a drug can activate receptors relative to the maximal response possible. Potency refers to the relative pharmacological activity of a compound or the relative ability of a drug to produce a given effect. Operationally, a drug's potency is determined by the plasma concentration of the drug (or the dose of the drug) necessary to produce a given effectthe lower the dose necessary to produce that effect or magnitude of effect, the more potent the drug
Answer to Question 2
The endothelial cells comprising the walls of the capillaries that supply blood to the brain are tightly packed together, with minimal pores between them. In addition, parts of glial cells may cover the outside of the capillaries. These comprise a lipid barrier through which non-lipid soluble drugs cannot pass, unless the molecules are compatible with transport proteins that can carry them across these membranes.
Intradermal drug administration: (a) cross section of skin showing depth of needle insertion Source:
Effect of Perceived Price of a Drug on Placebo Analgesia
Drug Classification and Description of Use
Types of pharmacokinetic drug–drug interactions.
Otic drug administration
The Drug Development Process