Questions about the absorption of drugs by the human system

Of course, it is the intravenous administration that works best, and the bioavailability of the drug is 100%. After the drug is absorbed in the small intestine, it first passes through the liver (part of it is metabolized) after entering the portal vein, and then enters the blood circulation of the whole body (at this time, the amount is considered the amount of real drug absorption, understand why intravenous injection is the best).However, because oral administration is the easiest method, everyone will choose this method if the first elimination is not very serious.

The method of respiratory tract administration is generally only in the case of the first elimination is very serious (that is, the medicine that is eaten is very little and really left in the end) (sublingual administration, rectal administration, etc.), more because the disease to be the first is a respiratory disease, and what is needed is the effect of local administration.

I just happened to study pharmacology this semester, I hope it will help you, and I won't talk about some special situations and the like, and I will hate people if I talk too much.

Even if we hate disease, but there will always be a moment when we are sick, and we have to take medicine when we are sick, so do you know how medicine dissolves in your body and is absorbed by your body?

(1) The physiological environment of the gastrointestinal tract.

2) Physiological factors of the circulatory system.

3) The effect of food on drug absorption.

4) Drug absorption characteristics of special populations.

The process by which a drug enters the bloodstream from the site of administration is called drug absorption.

The dosage form of the drug, the same drug with the same dose, due to different dosage forms, the absorption rate of the drug, the speed of drug efficacy and the strength of the drug will show obvious differences. For example, water and injection are more effective than oil, suspension and solid agents, but the maintenance time is shorter. The development of pharmacy in recent years.

Function: The dosage form of the drug provides many new dosage forms for clinical practice, such as the sustained-release preparation is the use of a matrix or coating with no pharmacological activity to prevent the rapid dissolution of the drug, so as to achieve the effect of non-constant slow release; Controlled-release preparations, on the other hand, can control the release of dust at a zero-level kinetic constant or near-constant velocity to maintain the constant absorption of the drug. These new dosage forms not only guarantee long-term efficacy, but also greatly benefit patients.

Factors influencing drug absorption:

1. Many factors can affect the absorption of drugs: such as the physical and chemical properties of drugs, dosage forms, preparations and routes of administration.

2. Among them, the route of administration has the most important impact on absorption, and the different routes of administration can directly affect the degree and speed of drug absorption.

3. Different routes of administration, the speed of drug absorption is as follows: inhalation, intramuscular injection, subcutaneous injection, oral administration, rectum**. Intravascular direct administration (eg, intravenous injection) has no absorption process because it enters the bloodstream directly.

Oral administration: Oral administration is the most commonly used method of administration, and its main absorption site is the small intestine, and the absorption method is mainly fat-soluble diffusion.

Answer]: The molecular form of C drug is easier to penetrate the biofilm than the ionic type, so weakly acidic drugs are not easy to dissociate and are easy to absorb in the sullen state of acidic environment. On the contrary, weakly alkaline drugs are not easy to dissociate and absorb in an alkaline environment. So the answer is c.

1) Gastric emptying rate The stomach is an important digestive organ of the human body, and it is also an important absorption site of many drugs, the first thing that the drug reaches after oral administration is the stomach, and stays in the stomach for a period of time, and then enters the small intestine through the duodenum, and the amount of gastric contents excreted into the small intestine per unit time is called the gastric emptying rate, the small intestine is the largest and most important absorption organ of the human body, and the absorption of drugs is also dominated by the small intestine, and the gastric emptying rate determines the speed at which the drug enters the small intestine, so it has a significant impact on the speed of the drug's effect, the strength of the effect and the length of the duration When the gastric emptying rate increases, absorption of most drugs is accelerated, which is beneficial for acid-unstable drugs or drugs that hope for quick relief, but for drugs that are mainly absorbed by the gastric mucosa (such as some weakly acidic drugs), their absorption is reduced, such as vitamins.

a.Route of administration.

b.Plasma protein binding rate.

c.Physical and chemical properties and dosage forms of drugs.

d.Absorb the source and bury the environment.

Correct answer to the case of empty Xiang: the binding rate of plasma egg hail and white ant.

Answer]: Letter D

The focus of this question is the absorption of drugs. Absorption refers to the process by which a drug enters the systemic circulation from the site of administration. In addition to intravascular administration, drugs must be absorbed before they can enter the body.

Different routes and methods of administration may have different in vivo processes. The absorption site of oral drugs is mainly the gastrointestinal tract; The surface area of the stomach is small, acidic drugs and liquid drugs are well absorbed, and the slippery drugs in the stomach are mainly passively transported, while the small intestine is divided into duodenum, jejunum and ileum, with a total area of about 200 m<>

Therefore, the small intestine, especially the duodenum, is the main site of oral drug absorption. Drugs that are not absorbed orally are absorbed in the musculature, mouth, rectum, lungs, nasal cavity, and eyes. So choose C. Ride Zen.

a.Physicochemical properties of the drug.

b.The dosage form of the drug.

c.Route of administration.

d.The rate at which the drug binds to plasma proteins.

e.The first-pass effect of the drug.

Correct Answer: The rate at which the drug binds to plasma proteins.