A simple equation for description of solute release I. Fickian and non-fickian release from non-swellable devices in the form of slabs, spheres, cylinders or discs
TL;DR: In this paper, a simple exponential relation Mt/M∞ = ktn is introduced to describe the general solute release behavior of controlled release polymeric devices, where Mt is the fractional release, t is the release time, k is a constant, and n is the diffusional exponent characteristic of the release mechanism.
About: This article is published in Journal of Controlled Release.The article was published on 1987-06-01. It has received 3256 citations till now. The article focuses on the topics: Controlled release.
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TL;DR: Chitin is the most abundant natural amino polysaccharide and is estimated to be produced annually almost as much as cellulose, and recent progress in chitin chemistry is quite noteworthy as mentioned in this paper.
Abstract: Chitin is the most abundant natural amino polysaccharide and is estimated to be produced annually almost as much as cellulose. It has become of great interest not only as an underutilized resource, but also as a new functional material of high potential in various fields, and recent progress in chitin chemistry is quite noteworthy. The purpose of this review is to take a closer look at chitin and chitosan applications. Based on current research and existing products, some new and futuristic approaches in this fascinating area are thoroughly discussed.
5,517 citations
TL;DR: In this paper, an exponential relation M t /M ∞ = kt n may be used to describe the Fickian and non-Fickian release behavior of release systems which are prepared by incorporation of a drug in a hydrophilic, initially glassy polymer.
3,522 citations
TL;DR: The aim of this article is to present a concise review on the applications of hydrogels in the pharmaceutical field, hydrogel characterization and analysis of drug release from such devices.
3,484 citations
Cites methods from "A simple equation for description o..."
...E-mail address: peppas@ecn.purdue.edu (N.A. Peppas). biological ¯uids [2,3]....
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...Studies by Khare and Peppas [69] examined the swelling kinetics of poly(MAA) or poly(acrylic acid) with poly(hydroxy ethyl methacrylate)....
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...Ritger and Peppas [172] performed analysis of the Fickian and non-Fickian diffusional behavior in terms of the value of the coef®cient, n....
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...Peppas and Merrill [36] modi®ed the original Flory± Rehner theory for hydrogels prepared in the presence of water....
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...Such expressions were developed by Silliman [42] and later modi®ed by Peppas and Merrill [43]....
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TL;DR: This Review discusses how different mechanisms interact and can be integrated to exert fine control in time and space over the drug presentation, and collects experimental release data from the literature and presents quantitative comparisons between different systems to provide guidelines for the rational design of hydrogel delivery systems.
Abstract: Hydrogel delivery systems can leverage therapeutically beneficial outcomes of drug delivery and have found clinical use. Hydrogels can provide spatial and temporal control over the release of various therapeutic agents, including small-molecule drugs, macromolecular drugs and cells. Owing to their tunable physical properties, controllable degradability and capability to protect labile drugs from degradation, hydrogels serve as a platform in which various physiochemical interactions with the encapsulated drugs control their release. In this Review, we cover multiscale mechanisms underlying the design of hydrogel drug delivery systems, focusing on physical and chemical properties of the hydrogel network and the hydrogel-drug interactions across the network, mesh, and molecular (or atomistic) scales. We discuss how different mechanisms interact and can be integrated to exert fine control in time and space over the drug presentation. We also collect experimental release data from the literature, review clinical translation to date of these systems, and present quantitative comparisons between different systems to provide guidelines for the rational design of hydrogel delivery systems.
2,457 citations
TL;DR: The present article is a comprehensive review of the current state of the art of mathematical modeling drug release from HPMC-based delivery systems and discusses the crucial points of the most important theories.
2,354 citations
References
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Book•
31 Dec 1959
TL;DR: In this paper, a classic account describes the known exact solutions of problems of heat flow, with detailed discussion of all the most important boundary value problems, including boundary value maximization.
Abstract: This classic account describes the known exact solutions of problems of heat flow, with detailed discussion of all the most important boundary value problems.
21,807 citations
Book•
01 Jan 1956
TL;DR: Though it incorporates much new material, this new edition preserves the general character of the book in providing a collection of solutions of the equations of diffusion and describing how these solutions may be obtained.
Abstract: Though it incorporates much new material, this new edition preserves the general character of the book in providing a collection of solutions of the equations of diffusion and describing how these solutions may be obtained
20,495 citations
Journal Article•
2,131 citations
TL;DR: An equation relating the rate of release of solid drugs suspended in ointment bases into perfect sinks is derived and the final expression is found to be surprisingly simple and convenient.
2,031 citations