Optimization and evaluation of ionically cross-linked alginate-hpmc nanospheres for encapsulation of bromelain as antiplatelet

Thrombus is blood congealment process (platelet) occurred in area of vein and is useful for preventing of bleeding occurrence. The considerable amount of thrombus in blood leads to blocked arteries and angina pectoris. The partial purification of bromelain originated from pineapple core (Ananas comosus [L.] Merr) with the specific activity of 124.38 U/mg had inhibition activity to the platelet aggregation of 86.48%. On the other hand, the proteolytic activity of bromelain was relatively stable in the first 4 hours. However, the proteolytic activity significantly decreased in the next 4 hours due to the influence of gastric fluid (pH 1.2). To overcome the problem, bromelain must be encapsulated into alginate-hpmc nanospheres cross-linked by cation (CaCl2). Based on the optimization result of the swelling index and the entrapment efficiency, the nanospheres with the composition of alginate-hpmc 1: 1 and 1:2 were the optimal formula and selected to encapsulate bromelain and be characterized by PSA and SEM. Alginate-hpmc nanospheres (1:1) had a particle size of 543.7±4.2 nm. The morphology of nanospheres were almost spherical and had a smooth surface. Moreover, the particle size of alginate-hpmc nanospheres (1:2) was 515.3±26.7 nm and the SEM micrographs showed the spherical nanospheres with slightly rough surface. The swelling degree, entrapment efficiency, PSA, and SEM data will relate to suitability of the nanospheres formulation to orally deliver bromelain.