Friday, October 21, 2011

A Study on Release of Propolis Extract Components From Emulsion-Type Dispersions

Medicina (Kaunas) 2011; 47 (6): 354-359

Background and Objective. Carrier development is one of the essential stages in the formulation of semisolid pharmaceutical dosage form for topical application. The stability of semisolid preparation during storage can be predicted from rheological testing. An adequate composition of semisolid preparation determines its stability and proper release of drug substance, and allows bypassing long-term heating and melting of the cream base components while incorporating complex extracts. Soft propolis extract, well known for its antimicrobial, antiviral, anti-inflammatory, and antioxidant effects, was chosen as a complex biologically active ingredient for the development of emulsion dispersion system.

The aim of this study was to evaluate the impact of physical-chemical characteristics of the carrier on the release rate of biologically active ingredients from the modeled dosage form in vitro, thus justifying the relevance of the carrier composition and applied technologies.

Material and Methods. Soft propolis extract (1%–3%) was incorporated into water-in-oil type emulsion. The quality of the model systems was evaluated referring to their viscosity, quantity of polyphenols and their rate of release from the preparation by applying an in vitro model. Quantitative determination of polyphenols was performed by spectrophotometry using a standard calibration curve of ferulic acid.

Results. The results showed that a stable homogeneous semisolid emulsion system containing soft propolis extract could be produced when the concentration of emulsifier was in the range of 3%–12%. The quantity of emulsifier had an impact on the viscosity of semisolid systems, but practically had no effect on the release rate of polyphenols from the cream matrix. The results also demonstrated that the added amount of soft propolis extract had a less significant effect than temperature of the system.

Conclusion. It was confirmed that changes in the viscosity of emulsion dispersion systems had no effect on the stability of model dispersion systems when temperature was increased, and this has to be evaluated to determine the storage conditions of the model preparations.

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