Discuss what is meant by pharmaceutics, pharmacokinetics and pharmacodynamics:
Pharmaceutics is used in pharmacy and in pharmaceutical sciences to cover a wide range of subject areas that are all associated with the steps to which a drug is subjected towards the end of its development. It covers the stages that follow on from the synthesis of a drug, its isolation and purification and testing for possible pharmacological effects and the absence of serious toxicological problems. Pharmaceutics can also be explained as the discipline of pharmacy which deals with the process of turning a new chemical entity into a medication which can be used safely and effectively by patients. This simply explains that it turns a drug into medicine. Pharmaceutics deals with the formulation of a pure drug substance into a dosage form.
Pharmacokinetics is the study of the processes that determine the concentration of drugs in body fluids and body tissues over time. The processes include drug absorption, drug distribution and drug elimination which include metabolism, and excretion. A simple way to explain the term is that it refers to what the body does to the drug. Pharmacokinetics also refers to the movement of a drug into the body, how the drug is distributed and finally how it leaves the body. Absorption is when the ingredients of the drug are absorbed into the bodily fluids and into cells. Distribution occurs when the active ingredients are spread around the different parts of the body. Metabolism is when the drug is broken down and transformed into an active form. Excretion occurs when the body gets rid of the drug. The pharmacokinetic properties of chemicals are affected by the route of administration and the dose of the administered drug. These may in turn affect the rate of absorption. For the drugs to be able to cross the membranes within the body it is necessary that they should be able to dissolve directly into the lipid bilayer of the membrane.
Pharmacodynamics is the study of the actions of drugs on target organs. A shorthand way of explaining it is that pharmacodynamics is what the drug does to the body. Pharmacodynamics also refers to the relationship between drug concentration at the site of action and the resulting effect, including the duration and intensity of therapeutic and adverse effects. This process simple explains the action of the drug within the body. This study starts at the binding of a drug to its target receptor, which then continues through a signal transduction pathway by which the receptor activates second messenger molecules, and ends with the ultimate description of intracellular processes altered by the impact of the drug. Pharmacodynamics provides a scientific basis for the selection and use of drugs to counteract specific pathophysiologic changes caused by disease or trauma. The resulting effect of a drug present at the site of action can be determined by that drug’s binding with a receptor. The concentration of the drug at the site of the receptor determines the intensity of the effect for most drugs.