Advertisement

Evaluation of Highly-Water Soluble Drug Physical State in Biodegradable Microcapsules

  • Dagnija LocaEmail author
  • O. Pugovics
  • L. Berzina-Cimdina
Conference paper
Part of the IFMBE Proceedings book series (IFMBE, volume 20)

Abstract

Microencapsulation of highly water soluble pharmaceuticals (solubility more than mg/ml) especially if high drug loading is required (more than 50%) is a big challenge. Biodegradable poly(lactic acid) (PLLA) as coating material and polyvinyl alcohol as surfactant were found suitable for this purpose. Active substance was microencapsulated using slightly modified water-in-oil-in-water technique which involves dissolving of the drug in water and polymer in methylene chloride and forming an emulsion in water using a surfactant. Procedure of microencapsulation was followed by filtration and drying of product obtained.

To evaluate the drug physical state in microcapsules powder X-Ray diffractometry (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used. Differential scanning calorimetry analysis confirmed absence of any drug-polymer interaction. At the same time decrease of glass transition temperature (Tg) of microcapsules testify that molecularly dispersed drug is forming a true solution with a polymer. X-ray diffraction patterns showed the changes of polymer crystallinity during the encapsulation procedure as well as decrease of crystallinity of the drug. SEM investigations showed the morphology of obtained product and demonstrated the drug location inside the capsule.

Keywords

microencapsulation drug delivery differential scanning calorimetry. X-Ray diffractometry 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Pistel K F, Kissel T. (2000) Effect of salt addition on the microencapsulation of proteins using w/o/w double emulsion technique. J.Microencapsulation 17:467–483CrossRefGoogle Scholar
  2. 2.
    Chaw C S, Yang Y Y, Lim I J et al (2003) Water-soluble betamethasone-loaded poly(lactide-co-glycolide) hollow microparticles as a sustained release dosage form. J.Microencapsulation 20:349–359Google Scholar
  3. 3.
    Sato T, Kanke M, Schroeder H J et al. (1988) Porous biodegradable microspheres for controlled drug delivery. I. Assessment of processing conditions and solvent removal techniques. Pharm. Res 5:21–30CrossRefGoogle Scholar
  4. 4.
    Chen X O, Yang Y Y, Wang L et al. (2001) Effects of inner water volume on the peculiar surface morphology of microspheres fabricated by double emulsion technique. J.Microencapsulation 18:637–649CrossRefGoogle Scholar
  5. 5.
    Soppimath K S, Aminabhavi T M. (2002) Ethyl acetate as a dispersing solvent in the production of poly(dl-lactide-co-glycolide) microspheres: effect of process parameters and polymer type. J.Microencapsulation 19:281–292CrossRefGoogle Scholar
  6. 6.
    Blanco M D, Sastre R L, Teijon C et al. (2006) Degradation behaviour of microspheres prepared by spray-drying poly(D,L-lactide) and poly(D,L-lactide-co-glycolide) polymers. Int J Pharm 326:139–147CrossRefGoogle Scholar
  7. 7.
    Nihant N, Schugens C, Grandfils C et al. (1994) Polylactide microparticles prepared by double emulsion/evaporation technique. I. Effect of primary emulsion stability. Pharm. Res. 11:1479–1484CrossRefGoogle Scholar
  8. 8.
    Brown M D (2003) Drug delivery systems in cancer therapy. Humana Press Inc., Totowa, NJCrossRefGoogle Scholar
  9. 9.
    Lamprecht A, Schefer U, Lehr C. (2000) Structural analysis of microparticles by confocal laser scanning microscopy. AAPS Pharmsci 6:article 17Google Scholar
  10. 10.
    Watts P J, Davies M C, Melia C D. Microencapsulation using emulsification/solvent evaporation: an overview of techniques and applications. (1990) Crit Rev Ther Drug 7:235–259Google Scholar
  11. 11.
    Tayade P T, Kale D R. (2004) encapsulation of water-insoluble drug by cross-linking technique: effect of process and formulation variables on encapsulation efficiency, particle size and in vitro dissolution rate. AAPS Pharmsci 6:article 12Google Scholar
  12. 12.
    O’Donnell P B, McGinity J W. (1997) Preparation of microspheres by the solvent evaporation technique. Adv Drug deliver rev 28:25–42CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2008

Authors and Affiliations

  1. 1.Riga Biomaterials innovation and development centerRiga Technical UniversityRigaLatvia
  2. 2.Latvian Institute of Organic SynthesisRigaLatvia

Personalised recommendations