MindMap Gallery Factors Affecting Drug Absorption Mind Map

Factors Affecting Drug Absorption Mind Map

Factors affecting drug absorption can be organized into a mind map to better visualize the relationships. This type of diagram typically includes main themes that encompass individual items such as the physical structure of the drug, route of administration, drug solubility, the integrity of the gastrointestinal tract, and other relevant factors that influence the absorption of drugs into the body. As illustrated in this mind map, the formulation is related to the physical properties of a drug, such as its particle size and lipid or water solubility. All these factors can impact the rate at which drugs are absorbed into our bloodstream. By mapping these factors in a visual representation, it becomes easier to understand and analyze them together. EdrawMind is a perfect mind mapping tool to create a similar drug absorption mind map.

Edited at 2023-01-17 15:21:56

Ibrahim Saad ALSAFYAH AL-qahtani

Factors Affecting Drug Absorption Mind Map

Ibrahim Saad ALSAFYAH AL-qahtani

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Outline

FACTORS AFFECTING ABSORPTION OF DRUGS

FACTORS RELATED TO DRUGS

1. Lipid/Water solubility

Lipid water solubility coefficientis the ratio of dissolution of drug in lipid as compared to water. Greater the lipid water solubility coefficient, more is the lipid solubility of the drug and greater is the absorption. Less the coefficient, less is the lipid solubility and less is the absorption.

Water film exists on the membranes so part of the drugs must be water soluble to cross this water film

2. Molecular size

Smaller the molecular size of the drug, rapid is the absorption.

different processes involved in absorption for different molecular sizes.

large molecular size undergo endocytosis or facilitated diffusion

smaller molecular sizes utilize aqueous diffusion or lipid channels

3. Particle size

Particle may be composed either of a single molecule or more than hundred molecules

Larger is the particle size, slower will be the diffusion and absorption and vice versa.

4. Degree of ionization

Different drugs are either acidic or basic and are present in ionized or unionized form, which is given by their pKa values.

5. Physical forms

Drugs may exist as solids, liquids or gases. Gases are rapidly absorbed than the liquids, while the liquids are rapidly absorbed than the solids. Thus the drugs in syrup or suspension form are rapidly absorbed than the tablets or capsules.

Volatile gases used in general anesthesia are quickly absorbed through the pulmonary route.

6. Chemical nature

Chemical nature is responsible for the selection of the route of administration of drug

heparin which is large molecular weight, and cannot be given orally. Simililarly, benzyl penicillin is degraded in the GIT, so is given parenterally.

7. Dosage forms

Dosage forms affect the rate and extent of absorption. A drug can be given in the form of tablets, capsules or transdermal packets. Injections may be aqueous or oily. This changes the rate of absorption.

Disintegration is the breaking up of the dosage form into smaller particles. When rapid is the disintegration, rapid will be the absorption.

Dissolution: After disintegration, the drug dissolves in the gastric juices, which is called dissolution. It is only then that the drug can be absorbed.

8. Formulation

When the drugs are formed, apart from the active form some inert substances are included. These are the diluents, excipients and the binders. Normally they are inert, but if they interact, they can change the bioavailability.

Examples include Na+ which can interact to decrease the absorption.

9. Concentration

According to Fick’s law, higher the concentration more flux occurs across the membrane. The rate is less affected than the extent of absorption.

FACTORS RELATED TO BODY

Area of absorption surface

Area of absorptive surface affects oral as well as other routes. Most of the drugs are given orally because of the large area of absorptive surface, so that greater absorption occurs. .

Vascularity

More the vascularity, more is the rate and extent of absorption and vice versa. In shock, blood supply to the GIT is less so the oral route of drug administration is affected. The blood flow to the peripheries is decreased, so absorption in those areas is diminished as well. Therefore, intravenous route is preferred in case of shock

The distribution of a weak electrolyte across a membrane will be determined by its pKa and the pH. Many drugs are weak electrolytes and tend to ionize according to environmental pH:

Presence of other substances

Foods or drugs may interact with the drugs to alter their rate of absorption. Especially for the drugs given orally, food can increase or decrease the absorption.

GI motility

GI mobility must be optimal for absorption of oral drugs. It should be neither increased nor decreased which may affect the rate or extent of absorption. Different diseases or drugs may alter the mobility

Functional integrity of absorption

Flattening and edema of mucosa decreaes absorption. Dysfunctional breach in the skin affects the absorption of topical drugs.

Diseases

a. Diarrhea Decreases absorption because of decreased contact time. b. Malabsorptive syndrome Decreases absorption c. Achlorhydria Acidic medium for acidic drugs is affected. d. Cirrhosis Cirrhosis affects portal circulation. Thus affecting metabolism of drugs. e. Emphysema Emphysema affects the absorption of volatile gases through the pulmonary route. f. Lipodystrophy Lipodystrophy decreases absorption. In diabetics, insulin might lose its affect.