GPAT Notes-1

SOME IMPORTANT POINTS . For GPAT & NIPER 

--lipid insoluble and water insoluble drugs are not absorbed from gut.

--most of the drugs are weakly acidic r weakly basic bcz stronger forms has high ability to form corresponding ions.

--most (90%) of drugs absorbed through passive diffusion(non ionic diffusion)

-- 0% protein binding - lisinopril..

--99% protein binding - oxyphenbutazone (metabolite of phenylbutazone)

--to show an effeicient drug action protien binding should be moderate ,insufficient protein binding shows less Vd & high protein binding lessens amount of druga at active site .

--extent of binding----- albumin > acid glycoprotein > lipoprotein > globulins.

--a drug having less Vd means its not bioavilable.(i.e decresed rate & amount of drug )

--bioavailability of------- parenteral > oral > rectal > topical.

--short acting barbiturates are due its rapid rate of distribution from brain.

--only unbounded drug(free form ) undergoes metabolism.

--the unbound drug 1st reaches liver from where it goes to other parts like kidneys

--only lipid soluble and non ionic drugs can enters brain.

--all orally administerd drugs undergo first pass metabolism.

--propanolol & Ca++channel blockers have extensive first pass metabolism.

--mainly metabolism occurs to exrete the drug.

--acidic drugs are exreted at basic pH &vice-versa.

--absorption ,distribution ,elimination follows 1st order kinetics.

--drugs showing 0 order elimination kinetics are asprin ,ethanol,phenytoin,theophyline,tolbutamide,phenylbutazone,wa

rfarin,heparin,salicylates etc..

--metabolism ,protein binding,carrier meiated transport at saturated conditions ,i.v infusion i.m implants ,osmatic pumps undergo 0 order kinetics i.e rate or process directly praportional to concentration or amount of reactants.