Drugs & Chemicals

Pharmacy is a transitional field between health sciences and chemical sciences and a profession charged with ensuring the safe use of medication. Traditionally, pharmacists have compounded and dispensed medications based on prescriptions from physicians. More recently, pharmacy has come to include other services related to patient care including clinical practice, medication review, and drug information.

Pharmacology meaning drug, and logos meaning science is the study of how substances interact with living organisms to produce a change in function. If substances have medicinal properties, they are considered pharmaceuticals. The field encompasses drug composition and properties, interactions, toxicology, therapies, medical applications, and antipathogenic capabilities.

Inside every branch of pharmacy there are many specialized branches related to many scientific disciplines. Many other sciences are also related to many branches of pharmacy: we can mention physical chemistry including mixing and mass transfer which makes basis for pharmaceutics. Biology (including molecular biology and biochemistry), physiology, organic chemistry, microbiology, parasitology , and also botany are all related in some way with one of pharmacy sciences.

Pharmacokinetics
The study (or kinetics) of drug absorption, distribution, metabolism, and excretion (ADME) is known as Pharmacokinetics. Simply put, it is what the body does to the drug. The processes of drug distribution and elimination (metabolism and excretion) are also known as drug disposition.

Pharmacodynamics
It is the study of effects of the drug, their mechanism of action, and relationship between drug concentrations at the site of action (receptor) and intensity of pharmacologic effect. It is what the drug does to the body.

Biopharmaceutics
The study of effects of physicochemical properties of the drug, the dosage from, and the route of administration on rate and extent of the drug absorption (bioavailability ) is known as Biopharmaceutics. The rate of drug release/dissolution, and the rate of absorption determine the distribution of the drug in the body.Bioavailability The rate and extent of the active ingredient that reaches the systemic circulation.

Pharmaceutical Equivalence
Drug products are pharmaceutically equivalent if contain same amounts of same active ingredient(s) in identical dosage forms administered by the same route of administration, and which meet existing standards of USP. The color, flavor, shape, inert ingredients, shelf life, and packaging could be different.

Bioequivalence
In order to meet bioequivalence criteria pharmaceutically equivalent products administered under similar conditions should have comparable bioavailabilities (within 80 to 120%). When log-transformed data are used, a range of 80 to 125% for the ratio of averages (AUC and Cmax) should be used. Further, the 90% confidence interval for the difference in the means of the log transformed data should be calculated. The antilogs of the calculated confidence interval should be contained entirely within [0.8, 1.2].

Therapeutic Equivalence
The pharmaceutical equivalents which provide the same therapeutic effect (control of a symptom or disease or other measuers) are said to be therapeutically equivalent.

Therapeutic Alternates
Drug products belonging to same pharmacological or therapeutic class that are expected to have similar therapeutic effects when administerd in therapeutically equivalent doses (i.e., prednisone and prednisolone)

Generic Substitution
The dispensing of a different branded or unbranded drug product for the drug product prescribed is known as generic substitution.

Pharmaceutical Alternates
Drugs product which differ in salt, ester or dosage form but are administered by the same route and contain the same amount(s) of same active ingredient(s) (i.e., erythromycin ethyl succinate and erythromycin palmitate; ampicillin suspension and ampicillin capsule).