Microencapsulation of shikonin in Pistacia lentiscus oleoresin matrix

Alkannin and shikonin (A/S) are potent pharmaceutical substances with a wide spectrum of biological activity like wound healing, antimicrobial, anti-inflammatory and anticancer [1,2]. A/S comprise the active ingredients of pharmaceutical preparations in several forms, such as powder form (A/S or a mixture of isohexenylnaphthazarin derivatives), olive oil extract of Alkanna tinctoria roots (Helixderm®, Epouloderm®) and sesame oil extract (Shiunko). Till date, A/S have not been used internally, as these are highly lipophilic substances.

The present study is a continuation of our research on formulating drug-delivery systems for bioactive naphthoquinones with improved physicochemical and pharmacokinetic properties. In these frames, shikonin has been encapsulated in microcapsules [3,4] and also inclusion complexes of alkannin, shikonin and isohexenylnaphthazarins in cyclodextrins have been formed [5].

The objective of the present study was to prepare shikonin-containing microcapsules with matrixes consisted of naturally occurring oleoresins, such as Pistacia lentiscus resin (mastic gum), as drug-delivery systems with enhanced stability and controlled release. The aim of the study was to compare the characteristics of the microcapsules prepared containing shikonin using as matrix Pistacia lentiscus resin with the ones previously reported [3,4].

Shikonin-containing microcapsules were prepared by the solvent evaporation method (o/w emulsion). Characterization of the produced microcapsules was performed by particle size analysis, optical microscopy, determination of the drug efficiency and loading and release studies.

References: 1. V.P. Papageorgiou et al. (1999) Ang Chem Int. Ed. 38: 270–300.

2. Papageorgiou, V.P. et al. (2006) Curr Org Chem 10: 2123–2142.

3. Assimopoulou, A.N. et al (2003)J Microencapsulation 20: 581–596.

4. Assimopoulou, A.N., Papageorgiou, V.P. (2004)J Microencapsulation 21: 161–173.

5. Assimopoulou, A.N., Papageorgiou, V.P. (2004) Biomedical Chromatography 18: 240–247.