Development and in-vitro characterization of 1-cysteine loaded alginate beads for oral delivery

The purpose of this work is to develop a biodegradable calcium alginate (Ca-alginate) bead formulation to provide controlled release of 1-cysteine (Cys) amino acid for oral drug delivery. Ca-alginate bead formulations were prepared successfully and reproducibly using calcium chloride as a cross-linking agent. The beads were then evaluated in terms of morphology, particle size, swellability, thermal behaviors, encapsulation efficiency, and in-vitro drug release at pH 1.2 and pH 7.4. The size of the beads was measured between 2.23 +/- 0.11 and 2.41 +/- 0.12 mm. In terms of thermal analysis, differential scanning calorimetry was utilized to ensure the encapsulation of Cys into bead formulation. Cys encapsulation was determined as 79.49 %+/- 1.12. Swelling index of blank beads were found to be in a range of 0.31-0.35 in HCl solution at pH 1.2; 0.98-1.08 in PBS buffer at pH 7.4. Alginate beads exhibited controlled release, followed the Weibull model which is consistent with the swelling pattern. The physico-chemical properties of the developed formulation indicate that the formulation is suitable for oral Cys delivery.