Development of slow release formulations of β-carotene employing amphiphilic polymers and their release kinetics study in water and different pH conditions.

β-carotene, a potent antioxidant, has been encapsulated and slow release (SR) formulations were prepared using laboratory synthesized poly(ethylene glycols) (PEGs) based functionalized amphiphilic copolymers. Encapsulation efficiency and loading capacity of the developed formulations were determined which ranged from 22.60 to 28.08 % and 2.2 to 2.8 % respectively. The release kinetics of β-carotene from developed formulations in water revealed increased solubility and prolonged stability of β-carotene. The formulations were further subjected to different pH conditions (viz., 1.8, 6.8 and 7.8) corresponding to human gastrointestinal tract to study the effect of pH on the release of β-carotene. The diffusion exponent (n values) ranged from the 0.1540 to 0.2342 for developed formulation. The results showed that developed slow release formulations were unaffected by the highly acidic conditions referring to the gastric environment of human body. However, the release of β-carotene was high at pH 7.8 and slightly higher at pH 6.8.