Absorption and Pharmacokinetics
Pharmacy
- Created by: natalie
- Created on: 17-03-14 20:24
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- Absorption Pharmacokinetics
- Right dose, form, route and time
- Routes by which solutes cross cell mem
- Carrier mediated transport
- Facilitated Diffusion- no atp
- examples:- ABC(atp binding casette transporter)
- examples:- SLC (solute carrier transporter)
- routes of administration
- enteral routes
- oral
- sublingual/buccal
- rectal
- parenteral routes
- intramuscular IM
- intravenous IV
- 100% Bioavailability
- =Biovalability
- F= auc ORAL/ auc IV
- 'F' affected by :
- drug formulaion
- first pass effect
- first pass effect/ bioavailabilty
- hepatic disease
- =Biovalability
- 100% Bioavailability
- inhaled
- subcutaneous SC
- enteral routes
- Carrier mediated transport
- Activation of cell membrane receptors
- Routes by which solutes cross cell mem
- Carrier mediated transport
- Facilitated Diffusion- no atp
- examples:- ABC(atp binding casette transporter)
- examples:- SLC (solute carrier transporter)
- routes of administration
- enteral routes
- oral
- sublingual/buccal
- rectal
- parenteral routes
- intramuscular IM
- intravenous IV
- 100% Bioavailability
- =Biovalability
- F= auc ORAL/ auc IV
- 'F' affected by :
- drug formulaion
- first pass effect
- first pass effect/ bioavailabilty
- hepatic disease
- =Biovalability
- 100% Bioavailability
- inhaled
- subcutaneous SC
- enteral routes
- Carrier mediated transport
- Routes by which solutes cross cell mem
- Pinocytosis
- Diffusion through (aq) channel/pore
- Drug= non ionised and low MW
- Diffusion through (aq) channel/pore
- Diffusion through (aq) channel/pore
- permeability coefficient: num of molecules crossing mem
- Diffusion through lipid bilayer
- Drug: lipid soluble
- Partition coefficient: solubility in mem
- Diffusion coefficient: diffusivity
- Diffusion through lipid bilayer
- pH and ionisation
- Most drugs weak acid or base
- WEAK BASES: BH+ ------- B + H+
- protonated BH+ ionised= cannot cross cell mem but B can
- WEAK ACIDS: HA---------- A- + H+
- protonated HA = non ionised = can cross cell mem
- WEAK BASES: BH+ ------- B + H+
- Absorption Pharmacokinetics
- Right dose, form, route and time
- Most drugs weak acid or base
- WEAK BASES: BH+ ------- B + H+
- protonated BH+ ionised= cannot cross cell mem but B can
- Barriers to absorption
- GI tract
- renal tubule
- BBB
- Barriers to absorption
- GI tract
- renal tubule
- Barriers to absorption
- Factors affecting rate and extent of absorption from GI tract
- gastric emptying time
- vomiting/diarrhoea
- blood supply
- Factors affecting rate and extent of absorption from GI tract
- gastric emptying time
- vomiting/diarrhoea
- Factors affecting rate and extent of absorption from GI tract
- food in gut
- co-administered with other drugs
- gut lumen
- metabolism in ;
- liver
- gut wall
- metabolism in ;
- First pass effect: extent of metabolism occuring before drug reaches systemic circulation
- metabolism in ;
- liver
- gut wall
- 1) drug taken orally
- 2) absorbed from GI tract into portal circulation
- 3) metabolised in liver
- 2) absorbed from GI tract into portal circulation
- metabolism in ;
- 1) drug taken orally
- 2) absorbed from GI tract into portal circulation
- 3) metabolised in liver
- 2) absorbed from GI tract into portal circulation
- ' F' : fraction of drug that enters systemic circulation
- better blood supply greater rate of absorption
- blood supply
- blood supply
- only unionised forms can be absorbed in his enviro
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