Formation of Water-Insoluble Gel in Dry-Coated Tablets for the Controlled Release of Theophylline.

Kaneko, Kaoru; Kanada, Ken; Miyagi, Masaharu; Saito, Nen; Ozeki, Tetsuya; Yuasa, Hiroshi; Kanaya, Yoshio

doi:10.1248/cpb.46.728

Cited by 20 publications

(10 citation statements)

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“…Addition of chitosan to the mixture further prolonged the induction period in the drug release process (48). Dry-coated tablets with alginate in the coating or alternatively alginate in the tablet core and a calcium-containing salt in the coating also showed a slow release rate (49,50). Gelatin capsules coated with alginate are demonstrated to remain intact as long as they are retained in the stomach, allowing for drug delivery selectively to the intestine (51).…”

Section: Diffusion Systemsmentioning

confidence: 99%

Alginate in Drug Delivery Systems

Tønnesen

Karlsen

2002

Drug Development and Industrial Pharmacy

1,284

613

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Alginates are established among the most versatile biopolymers, used in a wide range of applications. The conventional use of alginate as an excipient in drug products generally depends on the thickening, gel-forming, and stabilizing properties. A need for prolonged and better control of drug administration has increased the demand for tailor-made polymers. Hydrocolloids like alginate can play a significant role in the design of a controlled-release product. At low pH hydration of alginic acid leads to the formation of a high-viscosity ''acid gel.'' Alginate is also easily gelled in the presence of a divalent cation as the calcium ion. Dried sodium alginate beads reswell, creating a diffusion barrier decreasing the migration of small molecules (e.g., drugs). The ability of alginate to form two types of gel dependent on pH, i.e., an acid gel and an ionotropic gel, gives the polymer unique properties compared to neutral macromolecules. The molecule can be tailor-made for a number of applications. So far more than 200 different alginate grades and a number of alginate salts are manufactured. The potential use of the various qualities as pharmaceutical excipients has not been evaluated fully, but alginate is likely to make an important contribution in the development of polymeric delivery systems. This natural polymer is adopted by Ph.Eur. It can be obtained in an ultrapure form suitable for implants. This review discusses the present use and future possibilities of alginate as a tool in drug formulation.

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Section: Diffusion Systemsmentioning

confidence: 99%

Alginate in Drug Delivery Systems

Tønnesen

Karlsen

2002

Drug Development and Industrial Pharmacy

1,284

613

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“…It was widely used to produce microsphere, beads, microcapsule and tablets for drug delivery system and it showed long time effects and reduced side-effects of the drug (Kaneko et al, 1998). Bearing in mind their gelling ability, stabilizing properties and high viscosity in aqueous, sodium alginate and their derivatives were widely used in the food, cosmetics and pharmaceutical industries (Chunmei, Mingzhu, Jun, & Xu, 2009).…”

Section: Introductionmentioning

confidence: 99%

Synthesis and anticoagulant activity of sodium alginate sulfates

Fan

Jiang

et al. 2011

Carbohydrate Polymers

105

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“…When alginic acid is formed, it can stimulate tablet disintegration because it is insoluble but swells in water or high pH solution. CR matrix tablets composed of sodium alginate can be prepared by direct compression (107,108), granulation (109,110) and compression coating (109,111) or spray coating (112). However, work done on alginate-based matrix tablets is still limited.…”

Section: Hydrophilic Matricesmentioning

confidence: 99%

Controlled Release Systems Containing Solid Dispersions: Strategies and Mechanisms

et al. 2011

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In addition to a number of highly soluble drugs, most new chemical entities under development are poorly water-soluble drugs generally characterized by an insufficient dissolution rate and a small absorption window, leading to the low bioavailability. Controlled-release (CR) formulations have several potential advantages over conventional dosage forms, such as providing a uniform and prolonged therapeutic effect to improve patient compliance, reducing the frequency of dosing, minimizing the number of side effects, and reducing the strength of the required dose while increasing the effectiveness of the drug. Solid dispersions (SD) can be used to enhance the dissolution rate of poorly water-soluble drugs and to sustain the drug release by choosing an appropriate carrier. Thus, a CR-SD comprises both functions of SD and CR for poorly water-soluble drugs. Such CR dosage forms containing SD provide an immediately available dose for an immediate action followed by a gradual and continuous release of subsequent doses to maintain the plasma concentration of poorly water-soluble drugs over an extended period of time. This review aims to summarize all currently known aspects of controlled release systems containing solid dispersions, focusing on the preparation methods, mechanisms of action and characterization of physicochemical properties of the system.

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Formation of Water-Insoluble Gel in Dry-Coated Tablets for the Controlled Release of Theophylline.

Cited by 20 publications

References 1 publication

Alginate in Drug Delivery Systems

Alginate in Drug Delivery Systems

Synthesis and anticoagulant activity of sodium alginate sulfates

Controlled Release Systems Containing Solid Dispersions: Strategies and Mechanisms

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