Drug absorption in the stomach is passive transport

The small intestine is the main site of passive absorption of oral drugs

oral absorption

injection

Binding of drugs to plasma proteins

Blood circulation and vascular permeability

Organizational integration and accumulation

Blood-brain barrier, blood-fetal barrier transport

pH of body fluids and physical and chemical properties of drugs

Glomerular filtration: unable to filter out plasma proteins and drugs bound to plasma proteins

tubular reabsorption

Renal tubular secretion: The plasma protein binding rate of the drug does not affect the rate of renal tubular secretion

The main route of extrarenal excretion

The transport mechanism is mainly active transport

Drug half-life ×

Drug dissociation and lipid solubility

Drug dissolution rate and solubility

drug particle size

Drug crystal form

Excipients, dosage, and drug interactions

Preparation

Process technology

Ranking of different absorption rates for the same drug administration route

Drug release rate from injection

Oral dosage drug absorption rate

Refers to the amount of drug entering the blood circulation, which can be expressed by the area under the blood drug concentration-time curve

When the reference product is intravenously administered, the resulting ratio is called the absolute bioavailability

It refers to the speed at which a drug enters the systemic circulation. The ratio of blood drug concentration to peak time (tmax) is commonly used to indicate the speed at which a preparation is absorbed.

The ratio of the area under the drug-time curve of the preparation being tested to the area under the drug-time curve of intravenous injection

(AUC after oral administration of the same amount of drug/AUC after intravenous injection of a certain amount of drug)*100%

It refers to the highest blood drug concentration that can be achieved in the body after extravascular administration, also known as the peak.

It is a parameter related to the therapeutic effect and toxicity level.

refers to the time when blood drug concentration reaches its peak

Parameters that reflect the onset of drug action

Proportional to the total amount of drug absorption, it is a parameter that represents the degree of drug absorption.

The drug transport rate is proportional to the first power of the drug dose or blood drug concentration

Features

Drug transport rate is constant, regardless of drug dose or blood concentration

Features

Kinetic parameters that describe the rate of drug transport (elimination)

It is a proportional constant in the relationship between the amount of drug in the body and the blood drug concentration. It refers to the volume of body fluid required when the amount of drug in the body is evenly distributed according to the blood drug concentration.

Formula: Vd=X/C

Features