Chapter 3 Flashcards
Stomach body secretes
Stomach body pH
Acid secreting
PH 1.0- 3.5
Small intestine comprises
Duodenum, jejunum, ileum
pH of duodenum to ileum
5-7
7-8
Mucopolysaccharide layer lining the GI tract
Brush border
Drugs must dissolve and cross biological membranes to reach systemic circulation, what significantly impacts absorption
GI environment , including pH changes and enzymatic activity
Factors affecting absorption
Physiological factors
Biopharmaceutical factors
The ability of a drug to dissolve in a solvent (e.g., water,
Solubility
Factors affecting solubility
Polarity
Crystal structure
PH
Measures the drug’s lipophilicity (affinity for lipids) vs. hydrophilicity
(affinity for water).
Partition coefficient
Relation of partition coefficient to permeability
Hight partition coefficient = high permeability
The pH at which 50% of the drug is ionized
pKa
pKa in relation to weak acid and bases
Acidic = high pka = high unionized
Base = low pka = high unionized
Size of the molecule to diffuse easily across membrare
Smaller
Predicts drug-likeness based on molecular weight, Log P, hydrogen bond
donors, and acceptors
Rule of 5 (Lipinski’s Rule)
Relationship of melting point snd solubility
Hight melting point, low solubility
The fraction of the administered dose that reaches systemic circulation
Bioavailability F
Firstpass metabolism in relation to F
High first pass, low F
The ability of a drug to cross biological membrane
Permeability
Resistance to degradation in the body
Stability
Stability importance
Ensures the drug reaches its target intact
how the body processes a drug, including absorption, distribution,
metabolism, and excretion
Pharmacokinetics
Movement of the drug from the site of administration into the
bloodstream.
Absorption
Transport of the drug throughout the body
Distribution
Chemical modification of the drug to make it more excretable.
Metabolism
Major enzymes involved in phase 1 metabolism
Cytochrome P450 Enzymes
Rate at which the drug is removed from the body.
Clearance
Relation of vd
High vd , high permeability
From higher concentration to lower concentration.
Movement is caused by kinetic energy
Passive diffusion
High conse to low conse with the help of nutrients: glucose, amino acid
Can go against concentration gradient
Carrier mediated active transport
Do no need energy to be facilitated with transport protein
Fasilitated
Absorption of small molecules through water pores of biological membrane
Convective absorption
Movement of Ions which can NOT pass through pores and DO NOT have Carriers
EXOGENOUS ion + ENDOGENOUS ion = Neutral complex (Lipophilic)
Ion pair transport
