Improved drug loading and antibacterial activity of minocycline-loaded PLGA nanoparticles prepared by solid/oil/water ion pairing method
Received 27 October 2011
Accepted for publication 13 November 2011
Published 10 January 2012 Volume 2012:7 Pages 221—234
Review by Single anonymous peer review
Peer reviewer comments 3
Tahereh Sadat Jafarzadeh Kashi1, Solmaz Eskandarion1,2, Mehdi Esfandyari-Manesh3,4, Seyyed Mahmoud Amin Marashi5, Nasrin Samadi6, Seyyed Mostafa Fatemi1,7, Fatemeh Atyabi2,3, Saeed Eshraghi8, Rassoul Dinarvand2,3
1Dental Materials Department, Faculty of Dentistry, 2Department of Pharmaceutics, 3Nanotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, 4Department of Chemistry, Amirkabir University of Technology, Tehran, 5Department of Microbiology and Immunology, Faculty of Medicine, Babol University of Medical Sciences, Babol, 6Drug and Food Control Department, Faculty of Pharmacy, 7Research Center of Science and Technology in Medicine, 8Department of Microbiology, Tehran University of Medical Sciences, Tehran, Iran
Background: Low drug entrapment efficiency of hydrophilic drugs into poly(lactic-co-glycolic acid) (PLGA) nanoparticles is a major drawback. The objective of this work was to investigate different methods of producing PLGA nanoparticles containing minocycline, a drug suitable for periodontal infections.
Methods: Different methods, such as single and double solvent evaporation emulsion, ion pairing, and nanoprecipitation were used to prepare both PLGA and PEGylated PLGA nanoparticles. The resulting nanoparticles were analyzed for their morphology, particle size and size distribution, drug loading and entrapment efficiency, thermal properties, and antibacterial activity.
Results: The nanoparticles prepared in this study were spherical, with an average particle size of 85–424 nm. The entrapment efficiency of the nanoparticles prepared using different methods was as follows: solid/oil/water ion pairing (29.9%) > oil/oil (5.5%) > water/oil/water (4.7%) > modified oil/water (4.1%) > nano precipitation (0.8%). Addition of dextran sulfate as an ion pairing agent, acting as an ionic spacer between PEGylated PLGA and minocycline, decreased the water solubility of minocycline, hence increasing the drug entrapment efficiency. Entrapment efficiency was also increased when low molecular weight PLGA and high molecular weight dextran sulfate was used. Drug release studies performed in phosphate buffer at pH 7.4 indicated slow release of minocycline from 3 days to several weeks. On antibacterial analysis, the minimum inhibitory concentration and minimum bactericidal concentration of nanoparticles was at least two times lower than that of the free drug.
Conclusion: Novel minocycline-PEGylated PLGA nanoparticles prepared by the ion pairing method had the best drug loading and entrapment efficiency compared with other prepared nanoparticles. They also showed higher in vitro antibacterial activity than the free drug.
Keywords: nanoparticle, PEGylation, PLGA, ion pairing, minocycline, antibacterial
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