Dissolution mechanism of poorly water-soluble drug from extended release solid dispersion system with ethylcellulose and hydroxypropylmethylcellulose.
ABSTRACT The purpose of this study is to investigate the release mechanism of poorly water-soluble drug from the extended release solid dispersion systems with water-insoluble ethylcellulose (EC) and water-soluble hydroxypropylmethylcellulose (HPMC) (1:1). Indomethacin (IND) was used as a model of poorly water-soluble drug. Two kinds of solid dispersions were prepared by the solvent evaporation methods, which consist of the same formulation but exhibit different physical performance. It appeared that the dissolution behavior of IND depended on the structures of EC-HPMC matrices, which were governed by the preparation method. In addition, the dissolution behavior showed pH dependency that the dissolution rate of IND was slower in acidic medium than that in neutral medium. The experimental results revealed that the hydrophobic interaction between IND and EC occurred under lower pH and strongly delayed the dissolution rate of IND. The relationship between this hydrophobic interaction and the dissolution rate of IND was also proposed.
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ABSTRACT: In this study, poly(ethylene glycol) (PEG) was used as a hydrophilic polymer carrier to develop solid dispersion formulations for enhancing solubility and dissolution rate of pranlukast, one of poorly soluble drugs that has been broadly used for the treatment of asthma. PEG based solid dispersions with or without poloxamer were prepared by hot melting and solvent evaporation methods. The resultant solid dispersions were characterized by DSC and powder X-ray measurements, and their morphological properties were observed to be partially changed to amorphous state with reduced crystallinity. Dissolution and solubility tests showed that the solubility and dissolution rate of the solid dispersions were significantly enhanced. The solid dispersion formulation prepared by the hot melting method with a chemical composition of pranlukast:PEG:poloxamer = 1:5:1 demonstrated the most enhanced solubility and dissolution rate. The results suggest that the solid dispersions based on PEG and poloxamer are promising systems for the enhancement of solubility and bioavailability of pranlukast.Polymer Korea 01/2012; 36(1). · 0.43 Impact Factor
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ABSTRACT: Solid dispersions are considered as the one of the most emerging technologies for improving the practically water insoluble drugs dissolution profile thereby increasing the bioavailability of hydrophobic drugs. This article review provides the information about different types of solid dispersions based on their molecular arrangement and type of matrix material employed. Different methods of preparations of solid dispersions and recent advances in preparation methods have been highlighted. Various analytical tools employed in the characterization of solid dispersions are discussed.International Journal o f Advance d Chemical Science and Applications. 09/2014;
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ABSTRACT: To enhance the dissolution of poorly water-soluble drugs using a twin-screw kneader as a completely solvent-free method. Completely dry process was performed using a twin-screw kneader with hydrophilic porous silica in order to make solid dispersions of indomethacin, risperidone and fenofibrate at melting temperature of each drug. Changes in the molecular state of the drugs were investigated using the powder X-ray diffractometry and differential scanning calorimetry analyses. The dissolution studies were performed using the puddle method. On the powder X-ray diffraction, nitrogen adsorption and differential scanning calorimetry analyses, indomethacin and risperidone in solid dispersion changed to an amorphous state to adsorb onto silica pores. However, crystalline form of fenofibrate in solid dispersion was maintained in spite of the adsorption of fenofibrate onto silica pores. It was indicated that no functional groups were found interacting with silanol groups of silica surface resulting in the detection of the crystal form remained. A remarkable dissolution enhancement of the drugs from kneaded products was achieved by making the solid dispersion system with porous silica. Improvement of wettability and dispersibility, resulting from adsorption onto hydrophilic porous silica, was substantially contributed to the dissolution enhancement. Melt kneading process to make solid dispersion with porous silica was an effective technology to enhance the dissolution rate.