Encapsulation of folic acid (vitamin B9) into sporopollenin microcapsules: Physico-chemical characterisation, in vitro controlled release and photoprotection study

• Published in: Materials Science & Engineering C 2021-09, Vol.128, p.112271-112271, Article 112271
• Main Authors: Mohammed, Al-Shymaa Y., Dyab, Amro K.F., Taha, Fouad, Abd El-Mageed, Ahmed I.A.
• Format: Article
• Language: English
• Subjects: Bioavailability; Biocompatibility; Cellulose; Controlled release; Cytotoxicity; Drug delivery; Encapsulation; Folic acid; Food industry; Irradiation; Materials science; Microcapsules; Microencapsulation; pH effects; Photoprotection; Spores; Sporopollenin; Sunlight; Sustained release; Toxicity; Ultraviolet radiation
• ISSN: 0928-4931; 1873-0191
• DOI: 10.1016/j.msec.2021.112271

Folic acid (FA) is a crucial vitamin for all living creatures. However, it is susceptible to degradation under pH, heat, ultraviolet (UV) and day sunlight conditions, resulting in lowering its bioavailability. Therefore, a versatile protective encapsulation system for FA is highly required to overcome its inherent instability. We report the use of the robust Lycopodium clavatum sporopollenin (LCS) microcapsules, extracted from their natural micrometer-sized raw spores, for FA microencapsulation. The physico-chemical characterisation of the LCS microcapsules are comprehensively investigated before and after the microencapsulation using SEM, elemental, CLSM, FTIR, TGA/DTG and XRD analyses, revealing a successful FA encapsulation within the LCS in an amorphous form. The phenylpropanoid acids, responsible for the UV protection and the autofluorescence of the LCS, were found in the LCS as evidenced by FTIR analysis. TGA/DTG results revealed that the hemi-cellulose and cellulose are the major component of the LCS. A controlled and sustained release of FA from FA-loaded LCS were achieved where the release profile of FA-loaded LCS was found to be pH-dependent. The percentages of cumulative FA released after 10 h at 37 ± 0.5 °C were 45.5% and 76.1% in pH 1.2 and 7.4, respectively, ensuring controlled and slow release in simulated physiological conditions. The FA release kinetic studies indicated the prevalence of the Fickian diffusion mechanism in pH 1.2, while anomalous non-Fickian transport was ascribed for FA release in pH 7.4. The in vitro cytotoxicity assay revealed that the obtained formulations were biocompatible against the human skin fibroblast (HSF) cell line. The versatile LCS microcapsules exhibited intriguing photostability for FA under UV or sunlight irradiation. Concretely, the obtained FA sustained delivery and photoprotection properties of these LCS microcapsules validate their multifunctional characteristics, opening up intriguing applications in oral and topical drug delivery as well as in food industry. [Display omitted] •Folic acid, a vital vitamin, is degraded upon exposure to heat, UV, and sunlight.•Folic acid was encapsulated into natural and economic sporopollenin microcapsules.•The in vitro folic acid release from LCS was pH-dependent.•All formulations showed in-vitro biocompatibility against skin fibroblast cells.•Sporopollenin offered remarkable photoprotection for FA under UV and sunlight.