Sustained release of naltrexone from poly(n-isopropylacrylamide) microgels.
The release of the opioid antagonist naltrexone from neutral poly(N-isopropylacrylamide) (PNIPAAM) microgels and negatively charged PNIPAAM microgels containing acrylic acid groups (PNIPAAM-co-PAA) has been studied at various microgel and drug concentrations. The release curves were found to be well represented by the Weibull equation. The release rates were observed to be dependent on the microgel concentration. At most conditions, the release from the charged microgels was slower than for the neutral microgels. In addition, the charged microgels exhibited a release lag time, which was dependent on the microgel concentration. No significant lag time could be observed for the neutral microgels. Increasing the naltrexone concentration did not significantly affect the release rates from the neutral microgels, but the release from the charged microgels became faster. The microgels did not exhibit any significant cytotoxic effect on HeLa cells at the tested concentrations.
Department of Pharmacy, School of Pharmacy, University of Oslo, Blindern, N-0316, Oslo, Norway; Faculty of Engineering, Østfold University College, N-1757, Halden, Norway.
Anna-Lena
AL
Kjøniksen
Maria Teresa
MT
Calejo
Kaizheng
K
Zhu
Ana Maria S
AM
Cardoso
Maria C Pedroso
MC
de Lima
Amália S
AS
Jurado
Bo
B
Nyström
Sverre Arne
SA
Sande
D000179:Acrylates / Q000737:chemistry; D000180:Acrylic Resins / Q000737:chemistry*; D045744:Cell Line, Tumor; D003692:Delayed-Action Preparations / Q000737:chemistry*; D005782:Gels / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D009271:Naltrexone / Q000737:chemistry*
D000179:Acrylates; D000180:Acrylic Resins; D003692:Delayed-Action Preparations; D005782:Gels; C052970:poly-N-isopropylacrylamide; D009271:Naltrexone; C036658:acrylic acid
controlled release; drug delivery systems; macromolecular drug delivery; microencapsulation; microparticles; polymeric drug delivery systems