Application Of Solid Dispersions Research Articles

A mini review on solubility enhancement technique – solid dispersion

Many new drug substances have low aqueous solubility which can cause poor bioavailability after oral administration. Solid dispersions are one of the most promising strategies to improve the oral bioavailability of poorly water soluble drugs. By reducing drug particle size to the absolute minimum, and hence improving drug wettability, bioavailability may be significantly improved. Generally, SDs can be defined as a dispersion of active ingredients in molecular, amorphous and/or microcrystalline forms into an inert carrier. The application of solid dispersions is a useful method to increase the dissolution rate of drugs. This article is indented to combine literature on solid dispersion technology for solubility enhancement with special emphasis on mechanism responsible for the same by solid dispersion, various preparation methods and evaluation parameters.

Perspectives on Strategies Using Swellable Polymers in Solid Dispersions for Controlled Drug Release.

Poorly water-soluble drugs, which commonly face the issue of poor absorption and low bioavailability, have been under ongoing research of many formulation scientists for the past few decades. Solid dispersion is one of the most effective strategies in concerns for improving bioavailability of poorly water-soluble drugs. Either application of solid dispersions in dissolution enhancement of poorly water-soluble drugs or the use of swellable polymers in controlled drug release has been reported in pharmaceutical designs widely. However, a review of strategies of using swellable polymers in solid dispersion to take a full advantage of these polymers as a current perspective in facilitating drug bioavailability enhancement is still missing. In this review, we aim to provide a summary of techniques used to formulate a swellable polymer in solid dispersion especially a description of a suitable fabrication method in design of a controlled release solid dispersion.

ChemInform Abstract: Improved Dissolution Behavior of Lipophilic Drugs by Solid Dispersions: The Production Process as Starting Point for Formulation Considerations

AbstractReview: 143 refs.

Improved dissolution behavior of lipophilic drugs by solid dispersions: the production process as starting point for formulation considerations

Introduction:Many new drug substances have low aqueous solubility which can cause poor bioavailability after oral administration. The application of solid dispersions is a useful method to increase the dissolution rate of these drugs and thereby improve their bioavailability. So far, several methods have been developed to prepare solid dispersions. To obtain a product with the desired attributes, both the formulation and production processes should be considered.Areas covered:The most currently used methods to produce solid dispersions, such as the fusion method, hot melt extrusion, spray drying, freeze drying and supercritical fluid precipitation, are reviewed in this paper. In addition, the physicochemical characteristics of the obtained solid dispersions are discussed.Expert opinion:Solid dispersions can be successfully prepared by simple fusion, hot melt extrusion, spray drying, freeze drying and supercritical fluid precipitation. Hot melt extrusion, spray drying and freeze drying are processes that can be applied for large scale production. The simple fusion method is not very suitable for large scale production, but is particularly suitable for screening formulations. The most recent method to produce sold dispersions is supercritical fluid precipitation. The process conditions of this method need extensive investigation, in particular in relationship with the selection of the type of carrier and/or solvent. Both processes and formulation aspects strongly affect the characteristics of solid dispersion products. Furthermore, application of crystalline solid dispersions is gaining increasing interest because they are thermodynamically more stable than amorphous solid dispersions.

Application of solid dispersions with enteric coating agents to overcome some pharmaceutical problems.

A solid dispersion technique with enteric coating agents was applied to two drugs which present some pharmaceutical problems. The first drug, digoxin, is poorly water-soluble and chemically unstable in an acidic medium. The solid dispersions suppressed the dissolution rate of the drug in JP X 1st fluid (JP disintegration medium, pH 1.2), and improved the chemical stability.In JP X 2nd fluid (JP disintegration medium, pH 6.8), the solid dispersions showed rapid dissolution and supersaturation. It was concluded that this technique can provide an effective dosage form of digoxin for gastrointestinal absorption. The second drug, dipyridamole, is a poorly water-soluble organic base. The solid dispersion technique was applied to prepare a delayed absorption dosage form with good bioavailability. The solid dispersions showed suppressed a dissolution in an acidic medium, and gave supersaturation in a neutral or alkaline medium. Oral administration of this dosage form resulted in delayed absorption with good bioavailability.