title: Designed formulation based on α-tocopherol anchored on chitosan microspheres for pH-controlled gastrointestinal controlled release.
abstract: Chitosan microspheres were prepared and vitamin E (α-tocopherol) was anchored onto the polymer. The amount of α-tocopherol entrapped onto a gram of the microspheres based system was 13.4±0.4 mg. The microspheres modified with α-tocopherol were applied to vitamin E controlled release in a simulated gastrointestinal system. Characterizations were carried out by optical microscopy, FTIR and HPLC-UV techniques. For chitosan microspheres based system there was a 4.10% release, while for pure α-tocopherol the release was 25.53%. The percentage of α-tocopherol released at pH 6.8 was 13.10% for chitosan microspheres and 60.00% for free α-tocopherol. At pH 7.4, α-tocopherol release reached 51.30% and 92.88% for chitosan microspheres and pure α-tocopherol, respectively. α-tocopherol immobilized onto chitosan presented three distinct landings at each studied pH, whereas pure α-tocopherol presented only two established solubilization regions, one at pH 1.2, while between pH 6.8 and 7.4 it did not present any difference, establishing after 3.5h. Thus, the immobilization of α-tocopherol onto chitosan microspheres figures it as an efficient controlled release system.
authors.affiliation: QuiCSI Team, Institute of Chemistry, University of Brasília, C.P. 4478, 70904-970 Brasilia DC, Brazil. agscrixus@gmail.com
authors.forename: Alexandre G S
authors.initials: AG
authors.lastname: Prado
authors.forename: André L F
authors.initials: AL
authors.lastname: Santos
authors.forename: Alecio R
authors.initials: AR
authors.lastname: Nunes
authors.forename: Guilherme W
authors.initials: GW
authors.lastname: Tavares
authors.forename: Claudio M
authors.initials: CM
authors.lastname: de Almeida
mesh_terms: D000975:Antioxidants / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D002626:Chemistry, Pharmaceutical / Q000379:methods; D048271:Chitosan / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003692:Delayed-Action Preparations; D016503:Drug Delivery Systems / Q000379:methods; D041981:Gastrointestinal Tract / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008863:Microspheres; D015394:Molecular Structure; D010316:Particle Size; D013055:Spectrophotometry, Infrared; D024502:alpha-Tocopherol / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*
chemical_list: D000975:Antioxidants; D003692:Delayed-Action Preparations; D048271:Chitosan; D024502:alpha-Tocopherol