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| ==Etymology== | | ==Etymology== |
| French & Latin; French, from [[Latin]] absorption-, absorptio, from absorbēre | | French & Latin; French, from [[Latin]] absorption-, absorptio, from absorbēre |
− | *Date: [http://www.wikipedia.org/wiki/18th_Century 1741] | + | *Date: [https://www.wikipedia.org/wiki/18th_Century 1741] |
| ==Definitions== | | ==Definitions== |
| *1 a : the [[process]] of absorbing or of being absorbed — compare adsorption | | *1 a : the [[process]] of absorbing or of being absorbed — compare adsorption |
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| Absorption involves several [[phases]]. First, the [[drug]] needs to be administered via some route of administration (oral, via the skin, etc.) and in a specific dosage form such as a tablet, capsule, and so on. | | Absorption involves several [[phases]]. First, the [[drug]] needs to be administered via some route of administration (oral, via the skin, etc.) and in a specific dosage form such as a tablet, capsule, and so on. |
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− | In other situations, such as [http://en.wikipedia.org/wiki/Intravenous_therapy intravenous therapy], intramuscular injection, [http://en.wikipedia.org/wiki/Nasogastric_intubation enteral nutrition] and others, absorption is even more straight-forward and there is less variability in absorption and bioavailability is often near 100%. | + | In other situations, such as [https://en.wikipedia.org/wiki/Intravenous_therapy intravenous therapy], intramuscular injection, [https://en.wikipedia.org/wiki/Nasogastric_intubation enteral nutrition] and others, absorption is even more straight-forward and there is less variability in absorption and bioavailability is often near 100%. |
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− | Absorption is a primary [[focus]] in [http://en.wikipedia.org/wiki/Drug_development drug development] and [http://en.wikipedia.org/wiki/Medicinal_chemistry medicinal chemistry], since the drug must be absorbed before any medicinal [[effects]] can take place. Moreover, the drug's pharmacokinetic profile can be easily and significantly changed by [[adjusting]] factors that [[affect]] absorption. | + | Absorption is a primary [[focus]] in [https://en.wikipedia.org/wiki/Drug_development drug development] and [https://en.wikipedia.org/wiki/Medicinal_chemistry medicinal chemistry], since the drug must be absorbed before any medicinal [[effects]] can take place. Moreover, the drug's pharmacokinetic profile can be easily and significantly changed by [[adjusting]] factors that [[affect]] absorption. |
| ==Dissolution== | | ==Dissolution== |
− | In the most [[standard]] situation, a tablet is ingested and passes through the [http://en.wikipedia.org/wiki/Esophagus esophagus] to the [http://en.wikipedia.org/wiki/Stomach stomach]. Because the stomach is an aqueous [[environment]], this is the first place where a tablet will dissolve. | + | In the most [[standard]] situation, a tablet is ingested and passes through the [https://en.wikipedia.org/wiki/Esophagus esophagus] to the [https://en.wikipedia.org/wiki/Stomach stomach]. Because the stomach is an aqueous [[environment]], this is the first place where a tablet will dissolve. |
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− | The rate of dissolution is a key target for controlling the duration of a [[drug]]'s [[effect]], and as such, several dosage forms that contain the same active ingredient may be available, differing only in the rate of dissolution. If a drug is supplied in a form that is not readily dissolved, the drug may be released more [[gradually]] over time with a longer duration of [[action]]. Having a longer duration of action may improve [http://en.wikipedia.org/wiki/Compliance_(medicine) compliance] since the medication will not have to be taken as often. Additionally, slow-release dosage forms may maintain concentrations within an acceptable therapeutic range over a long period of time, as opposed to quick-release dosage forms which may result in sharper peaks and troughs in serum concentrations. | + | The rate of dissolution is a key target for controlling the duration of a [[drug]]'s [[effect]], and as such, several dosage forms that contain the same active ingredient may be available, differing only in the rate of dissolution. If a drug is supplied in a form that is not readily dissolved, the drug may be released more [[gradually]] over time with a longer duration of [[action]]. Having a longer duration of action may improve [https://en.wikipedia.org/wiki/Compliance_(medicine) compliance] since the medication will not have to be taken as often. Additionally, slow-release dosage forms may maintain concentrations within an acceptable therapeutic range over a long period of time, as opposed to quick-release dosage forms which may result in sharper peaks and troughs in serum concentrations. |
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− | The rate of dissolution is described by the [http://en.wikipedia.org/wiki/Arthur_Amos_Noyes Noyes]-[http://en.wikipedia.org/wiki/Willis_Rodney_Whitney Whitney] equation as shown below: | + | The rate of dissolution is described by the [https://en.wikipedia.org/wiki/Arthur_Amos_Noyes Noyes]-[https://en.wikipedia.org/wiki/Willis_Rodney_Whitney Whitney] equation as shown below: |
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| [[File:Absorption.jpg]] | | [[File:Absorption.jpg]] |
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| :[[File:Absorption_2.jpg]] | | :[[File:Absorption_2.jpg]] |
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− | * A is the [http://en.wikipedia.org/wiki/Surface_area surface area] of the solid. | + | * A is the [https://en.wikipedia.org/wiki/Surface_area surface area] of the solid. |
| * C is the [[concentration]] of the solid in the bulk dissolution [[medium]]. | | * C is the [[concentration]] of the solid in the bulk dissolution [[medium]]. |
| * Cs is the concentration of the solid in the [[diffusion]] layer surrounding the solid. | | * Cs is the concentration of the solid in the [[diffusion]] layer surrounding the solid. |
− | * D is the diffusion [http://en.wikipedia.org/wiki/Coefficient coefficient]. | + | * D is the diffusion [https://en.wikipedia.org/wiki/Coefficient coefficient]. |
| * L is the diffusion layer thickness. | | * L is the diffusion layer thickness. |
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− | As can be inferred by the Noyes-Whitney equation, the rate of dissolution may be [[modified]] primarily by altering the surface area of the solid. The surface area may be [[adjusted]] by altering the [[particle]] size (e.g. [http://en.wikipedia.org/wiki/Micronization micronization]). The rate of dissolution may also be altered by choosing a suitable [http://en.wikipedia.org/wiki/Polymorphism_(materials_science) polymorph] of a compound. Specifically, [[crystalline]] forms dissolve slower than amorphous forms. | + | As can be inferred by the Noyes-Whitney equation, the rate of dissolution may be [[modified]] primarily by altering the surface area of the solid. The surface area may be [[adjusted]] by altering the [[particle]] size (e.g. [https://en.wikipedia.org/wiki/Micronization micronization]). The rate of dissolution may also be altered by choosing a suitable [https://en.wikipedia.org/wiki/Polymorphism_(materials_science) polymorph] of a compound. Specifically, [[crystalline]] forms dissolve slower than amorphous forms. |
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− | Also, coatings on a tablet or a pellet may act as a barrier to reduce the rate of dissolution. Coating may also be used to modify where dissolution takes place. For example, [http://en.wikipedia.org/wiki/Enteric_coating enteric coatings] may be applied to a drug, so that the coating only dissolves in the basic environment of the intestines. This will prevent release of the drug before reaching the intestines. | + | Also, coatings on a tablet or a pellet may act as a barrier to reduce the rate of dissolution. Coating may also be used to modify where dissolution takes place. For example, [https://en.wikipedia.org/wiki/Enteric_coating enteric coatings] may be applied to a drug, so that the coating only dissolves in the basic environment of the intestines. This will prevent release of the drug before reaching the intestines. |
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− | Since solutions are already dissolved, they do not need to undergo dissolution before being absorbed.[http://en.wikipedia.org/wiki/Absorption_%28pharmacokinetics%29] | + | Since solutions are already dissolved, they do not need to undergo dissolution before being absorbed.[https://en.wikipedia.org/wiki/Absorption_%28pharmacokinetics%29] |
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| [[Category: Chemistry]] | | [[Category: Chemistry]] |