title: In vitro transdermal and biological evaluation of ALA-loaded poly(N-isopropylacrylamide) and poly(N-isopropylacrylamide-co-acrylic acid) microgels for photodynamic therapy.
abstract: Poly(N-isopropylacrylamide) (PNIPA) and Poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPA-co-AA)) microgels loaded with 5-aminolevulinic acid (ALA) were prepared by the spray-drying method. The amount of drug loaded was 290 µg ALA/mg microgel for PNIPA and 244 µg ALA/mg microgel for P(NIPA-co-AA) microgels. Maximum in vitro drug release took place within 15-30 min for PNIPA and 1-1.5 h for P(NIPA-co-AA) microgels as a function of pH, at 37°C. Transdermal delivery from microgels showed permeation fluxes 10 times higher than the passive diffusion flux. The cytotoxicity of microgels synthesized in HeLa cells after the application of photodynamic therapy (PDT) was superior compared with the administration of ALA in solution alone. Finally, the use of these microgels as a delivery vehicle for ALA constitutes a system capable of enhancing its topical administration and PDT effectiveness.
authors.affiliation: Departamento Sistemas de Baja Dimensionalidad, Superficies y Materia Condensada. Instituto de Química Física Rocasolano, CSIC, Madrid, Spain. c.gomez@iqfr.csic.es
authors.forename: Clara
authors.initials: C
authors.lastname: Gómez
authors.forename: Marta
authors.initials: M
authors.lastname: Benito
authors.forename: Issa
authors.initials: I
authors.lastname: Katime
authors.forename: José María
authors.initials: JM
authors.lastname: Teijón
authors.forename: María Dolores
authors.initials: MD
authors.lastname: Blanco
mesh_terms: D000178:Acrylamides / Q000494:pharmacology*; D000180:Acrylic Resins; D000279:Administration, Cutaneous; D000622:Aminolevulinic Acid / Q000494:pharmacology*; D000818:Animals; D016503:Drug Delivery Systems; D004353:Drug Evaluation, Preclinical; D006367:HeLa Cells; D006801:Humans; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D011108:Polymers / Q000494:pharmacology*; D051381:Rats
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; C090629:N-isopropylacrylamide-acrylic acid copolymer; D017319:Photosensitizing Agents; D011108:Polymers; C052970:poly-N-isopropylacrylamide; D000622:Aminolevulinic Acid