Drug Absorption

Drug Administration Routes

intravenous, oral, buccal, sublingual, rectal, subcutaneous, transdermal, topical, inhaled, and intramuscular.

Bioavailability

The proportion of a drug that enters systemic circulation after administration

drug factors affecting absorption

molecular size and lipid solubility

patient factors affecting drug absorption

surface area and blood flow

Drug Absorption Mechanisms

passive diffusion, carrier-mediated transport, pore-mediated transport and pinocytosis

Solid dosage forms

Taken orally. Require disintegration and dissolution for absorption

absorption of liquid forms

rapid

modified release tablets

release drug slowly over time

immediate-release tablets

break down in around 30 minutes

Preclinical Testing

Extensive testing in cell culture and animals to predict/measure pharmacokinetic properties

Investigational New Drug (IND)

Covers preclinical studies, manufacturing, clinical study protocols, and investigational plan for clinical development.

IND Pharmacology Section

Preclinical animal studies, pharmacokinetics, justification for human testing, in vitro models, and in silico models predicting pharmacokinetics in diverse patients.

Phase I IND

• concise pharmacology section focused on distribution

• toxicology

• qualifications of individuals suggesting human trials