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

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 3.5 h. Thus, the immobilization of α-tocopherol onto chitosan microspheres figures it as an efficient controlled release system.

Graphical abstract.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Development of low-cost and simple system to obtain chitosan microspheres. ► Interaction of α-tocopherol onto chitosan microspheres surface. ► Development of controlled release system based on α-tocopherol anchored onto chitosan microspheres. ► Controlled release studies of α-tocopherol in pH-controlled mimetized gastrointestinal system. ► Development of new controlled release system of low-cost.