Philippine Pharmacist Licensure Exam key terms

The rate and extent to which the active ingredient or therapeutic moiety is absorbed from a dosage form and becomes available at the site of action, usually assessed from plasma concentration-time data after extravascular administration.

The absence of a significant difference in the rate and extent of absorption between two pharmaceutically equivalent products administered at the same molar dose, established statistically from comparative bioavailability studies in human subjects.

Presystemic metabolism of an orally administered drug in the intestinal wall and liver before it reaches systemic circulation, reducing the fraction of dose reaching the general circulation and often necessitating higher oral doses.

The time required for the plasma concentration or amount of drug in the body to decrease by one half during elimination; determines dosing interval and time to reach steady state, approximately four to five half-lives.

An apparent proportionality constant relating the amount of drug in the body to its plasma concentration; a high value suggests extensive tissue distribution, while a low value suggests confinement to plasma water.

The volume of plasma from which a drug is completely removed per unit time by all elimination pathways; it determines the maintenance dose rate needed to sustain a target steady-state concentration.

A ratio comparing the dose producing toxicity or lethality to the dose producing the desired effect, commonly TD50 divided by ED50; a small ratio signals narrow margin of safety requiring monitoring.

A drug whose effective and toxic doses are close, so small changes in plasma concentration risk therapeutic failure or toxicity; examples include digoxin, warfarin, lithium, phenytoin, and theophylline, requiring therapeutic drug monitoring.

A ligand that binds a receptor and activates it to produce a full or partial biological response, possessing both affinity for the binding site and intrinsic efficacy to trigger signal transduction.

A ligand that binds a receptor with affinity but lacks intrinsic efficacy, blocking agonist-mediated responses; competitive antagonists shift dose-response curves rightward, while noncompetitive antagonists reduce maximal response.

An agonist that binds and activates a receptor but produces less than the maximal response of a full agonist, acting as a competitive antagonist when a full agonist is present.

A pharmacologically inactive derivative of a drug that undergoes enzymatic or chemical conversion in the body to release the active moiety, often used to improve absorption, taste, stability, or targeting.

A carbon atom bonded to four different substituent groups, creating non-superimposable mirror-image forms called enantiomers that may differ in pharmacologic activity, metabolism, and toxicity.

One of a pair of stereoisomers that are non-superimposable mirror images of each other; enantiomers rotate plane-polarized light in opposite directions and can have distinct biological activities.

An equimolar mixture of two enantiomers that is optically inactive because the opposing rotations cancel; many racemic drugs contain one enantiomer carrying most of the therapeutic activity.

The amount of strong acid or base that a buffer solution can absorb per unit pH change; it is greatest near the pKa and increases with buffer concentration, important in pharmaceutical formulation and biological fluids.

An equation relating pH, pKa, and the ratio of ionized to unionized species of a weak acid or base; used to predict drug ionization, absorption across membranes, and buffer composition.

The negative logarithm of the acid dissociation constant of a drug or functional group; it indicates the pH at which ionized and unionized forms are equal and predicts ionization behavior at physiological pH.

A volumetric analytical method in which a metal ion in solution is titrated with a chelating ligand such as disodium edetate, with the endpoint detected by a metal-ion indicator like murexide or eriochrome black T.

A coulometric or volumetric method for determining water content in pharmaceutical samples, based on the quantitative reaction of water with iodine and sulfur dioxide in the presence of a base and methanol.

A highly pure, stable, nonhygroscopic reagent used to standardize a volumetric solution or to prepare a solution of known concentration directly by accurate weighing, such as potassium hydrogen phthalate or sodium carbonate.

A naturally occurring nitrogen-containing basic organic compound of plant origin, often pharmacologically potent, such as morphine, quinine, atropine, and vincristine; usually extracted by acid-base partitioning.

A natural product in which a sugar moiety is linked through a glycosidic bond to a non-sugar aglycone; examples include cardiac glycosides like digoxin and saponin glycosides.

A chemically defined constituent of a crude drug or herbal preparation used to identify the material, assess quality, and standardize extracts when the active principle is unknown or unmeasurable.

The study of medicinal substances of natural origin, covering their botanical and biological sources, cultivation, collection, chemistry, standardization, and therapeutic uses in drug discovery.

The process by which a solid dosage form releases drug into solution under standardized conditions of temperature, agitation, and medium; a critical quality attribute predicting oral absorption and batch consistency.

A relationship in which two products contain the same amount of the same active ingredient in the same dosage form and meet identical or comparable compendial standards, but without implying comparable in vivo performance.

A set of regulatory requirements ensuring that pharmaceutical products are consistently produced and controlled according to quality standards, covering premises, personnel, equipment, documentation, validation, and quality control.

Documented evidence providing a high degree of assurance that a process, method, or system consistently produces a result meeting predetermined specifications and quality attributes.

The part of Good Manufacturing Practice concerned with sampling, specifications, testing, and release procedures that ensure materials and products are not released until their quality has been judged satisfactory.

The date placed on a drug product label until which the manufacturer guarantees the product will retain its identity, strength, quality, purity, and potency when stored under labeled conditions.

A drug or precursor listed under the Comprehensive Dangerous Drugs Act because of abuse potential or dependence liability, subject to special licensing, prescription, recordkeeping, and dispensing restrictions.

A written or electronic order from a licensed prescriber for dispensing a specific drug product to a named patient, containing required elements such as drug name, strength, quantity, directions, and prescriber signature.

The practice of substituting a therapeutically equivalent, less expensive generic product for a prescribed brand-name drug, permitted under Philippine law when the prescriber does not prohibit substitution in writing.

The credential issued by the Professional Regulation Commission after passing the licensure examination, required by law to practice pharmacy, supervise drug outlets, and dispense medicines in the Philippines.

Structured learning activities required of licensed pharmacists to maintain and update competence; credits must be earned within a compliance period to renew the professional identification card.

Any noxious and unintended response to a drug occurring at doses normally used in humans for prophylaxis, diagnosis, or therapy, excluding therapeutic failure and intentional overdose.

The science and activities relating to detection, assessment, understanding, and prevention of adverse effects or any other drug-related problem, including spontaneous reporting and signal evaluation.