Physiological Pharmaceutics

294 GlossaryPectoral muscle Chest muscle.Penbutolol A ß adrenergic blocking drug.Penetration enhancers Compounds which promoteabsorption of drugs. Usually their action isnon-specific.Penicillin One of a group of antibioticsbiosynthesized by several species of mold.Pepsin Chief enzyme of gastric juice which convertsproteins into proteoses and peptones. It isformed by the chief cells of the gastric glands.Pepsinogen Pepsin precursor.Peptides Building blocks of proteins formed fromamino acids.Perfusion Passing of fluid through spaces.Perimysium Connective tissue sheath whichenvelops each bundle of muscle fibres.Periodontal disease Disease of the supportingstructures of the teeth.Periodontitis Inflammation or degeneration or bothof the dental periostium, alveolar bone,cementum and adjacent gingiva.Periodontosis Any degenerative disease of theperiodontal tissues.Peritoneum The serous membrane reflected over theviscera and lining of the abdominal cavity.Persorption Sloughing off of cells from the tips ofvilli in the small intestine leaves a gap throughwhich particles can enter the blood stream.Pessaries drug delivery device or supportingstructure inserted into the vagina.Pethidine Also known as Peridine. Opioid analgesicused for moderate to severe pain.Petrolatum A purified semisolid mixture ofhydrocarbons obtained from petroleum.Petrolatum based jelly A purified semisolid mixtureof hydrocarbons obtained from petroleumwhich is decolourised and stabilized.Peyer’s patches An aggregation of lymph nodulesfound chiefly in the ileum near to its junctionwith the colon. They are circular or oval andabout 1 cm wide and 2–3 cm long.pH Measurement of acidity and alkalinity rangingfrom 0 (acid) to 14 (alkaline). pH 7 is neutral.Formula is pH=-log[H+]. As the scale islogarithmic, there is a 10 fold differencebetween each unit.pH-partition hypothesis The principle that drugpassage through a membrane is controlled bythe ph of the environment since this controlsthe ionization of the drug, which can only beabsorbed in its unionized state.Phagocytosis Ingestion and digestion of bacteria andparticles by phagocytes.Pharmacokinetics Study of the metabolism and actionof drugs with particular emphasis on the timerequired for absorption, duration of action,distribution in the body and method of excretion.Phenobarbital A hypnotic drug.long-acting sedativeand anti-convulsant.Phenol red A dye used an a pH indicator.Phenylalanine An aromatic amino-acid.Phenylephrine Vasoconstrictor and pressor drugsimilar to adrenaline, but more stable.Phlebitis Irritation of a blood vessel.Phonation Speaking; the act of making a sound.Phosphatidylcholine (PC) One of the commonestphospholipids, consisting of a glycerolbackbone in which the 1- and 2-alcohol groupsare esterified to fatty acids, while the 3-alcoholis esterified to a phosphate group. Thephosphate is in turn joined to a headgroup,which is choline in the case ofphosphaticylcholine.Phosphatidylethanolamine (PE) A phospholipid inwhich the headgroup is ethanolamine. Seephosphatidylycholine.Phosphatidylinositol (PI) A phospholipid in which theheadgroup is inositol. See phosphatidylycholine.Phosphatidylserine (PS) A phospholipid in which theheadgroup is serine. See phosphatidylycholine.Phosphoglucomutase An enzyme whichinterconverts glucose-1 phosphate and glucose-6-phosphate.Phospholipid; stealth A phospholipid carrying anethylene oxide chain attached to theheadgroup, which forms a heavily hydratedouter layer when the phospholipid is formedinto liposomes. This reduces the extent whichthe liposomes are recognised by thereticuloendothelial system.Pilocarpine Alkaloid which is used to causecontraction of the pupil.Pituitary hormones Hormones secreted from thepituitary gland which regulate many bodyprocesses. These include growth hormone,adrenocorticotropic hormone which regulatesfunctional activity of the adrenal cortex,thyrotropic hormone which regulates activityof the thyroid gland and gonadotrophichormone amongst others.Plaque A patch on the skin or on a mucous surface.A blood platelet. Dental plaque is a gummymass of microorganisms that grows on thecrowns and spreads along the roots of teeth.These are the forerunner of caries.Plasma membrane The outer membrane of the cell,composed of phospholipids, proteins, etc.Platelets A round or oval disk 2 to 4 µm in diameterfound in the blood. They are important forcoagulation.Plicae semilunares Transverse fold of mucosa of thelarge intestine lying between sacculations.Pluronic ® Trade name for a range of poly (ethyleneoxide)-poly (propylene oxide)-poly (ethyleneoxide) triblock copolymers widely used in drugformulation and delivery.pMDI See pressurized metered dose inhalers.Polyacrylic acid A copolymer of acrylic acid.Polyalkylene glycols Block copolymers of the formHO-(R-O)-H where R is any alkyl group.Polyethylene glycol and polypropylene glycolare the most commonly encountered.Polycarbophil Generic name for crosslinked acrylicacid copolymers used as thickening agents andbioadhesives.Polyethylene One of the earliest polymers, consisting