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The rate of dissolution is described by the Noyes–Whitney equation as shown below: = Where: is the rate of dissolution. A is the surface area of the solid. C is the concentration of the solid in the bulk dissolution medium.
As the stomach has an aqueous environment, it is the first place where the pill can dissolve. The rate of dissolution is a key element in controlling the duration of a drug's effect. For this reason, different forms of the same medication can have the same active ingredients but different dissolution rates.
Whether a drug is taken with or without food will also affect absorption, other drugs taken concurrently may alter absorption and first-pass metabolism, intestinal motility alters the dissolution of the drug and may affect the degree of chemical degradation of the drug by intestinal microflora.
The absorption of sublingual estradiol can be attributed to the rich vascularization under the tongue. [152] With administration of an oral estradiol tablet sublingually, complete dissolution of the tablet occurs within a few minutes and circulating levels of estradiol begin to rise within 5 minutes. [152]
Instead of diffusion, the drug release depends on the solubility and thickness of the coating. Because of this mechanism, the dissolution will be the rate limiting factor for drug release. [3] Dissolution systems can be broken down to subcategories called reservoir devices and matrix devices. [6]
During the dissolution testing, "sink condition" is a mandatory requirement, otherwise when the concentration begins to get too close to the saturation point, even though the total soluble amount still remains constant, the dissolution rate will gradually begin to reduce in significant amounts, enough to corrupt the test results. . [2] [3] [4]
absorption: 1) The process of one material (absorbate) being retained by another (absorbent); this may be the physical solution of a gas, liquid, or solid in a liquid, attachment of molecules of a gas, vapour, liquid, or dissolved substance to a solid surface by physical forces, etc. In spectrophotometry, absorption of light at characteristic ...
In the pharmaceutical industry, drug dissolution testing is routinely used to provide critical in vitro drug release information for both quality control purposes, i.e., to assess batch-to-batch consistency of solid oral dosage forms such as tablets, and drug development, i.e., to predict in vivo drug release profiles. [1]