Designed formulation based on α-tocopherol anchored on chitosan microspheres for pH-controlled gastrointestinal...

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.