Enhancing therapeutic effects alginate microencapsulation of thyme and calendula oils using ionic gelation for controlled drug delivery

This study focuses on encapsulating and characterizing essential oils such as thyme and calendula oils, which are known for their therapeutic properties but are limited in pharmaceutical formulations due to their low water solubility and instability, with alginate microspheres. Alginate presents an excellent option for microencapsulation due to its biocompatibility and biological degradability. The ionic gelation (IG) technique, based on the ionic binding between alginate and divalent cations, allows the formation of hydrogel materials with high water content, mechanical strength, and biocompatibility. The microspheres were characterized using FT-IR, SEM, and swelling analyses. After determining the encapsulation efficiency and drug loading capacity, the microspheres were subjected to dissolution studies under simulated digestion conditions. It was observed that the swelling percentage of the microspheres in simulated gastric fluid (SGF) ranged from ∼15% to 100%, while in simulated intestinal fluid (SIF) it ranged from ∼150% to 325%. Thyme oil, with low viscosity, exhibited higher encapsulation efficiency than marigold oil. The highest encapsulation efficiency was observed in A-TO-2 microspheres, while the highest drug loading capacity was observed in A-TO-5 microspheres. During the examination of the dissolution profiles of the microspheres, dissolution rates ranging from 10.98% to 23.56% in SGF and from 52.44% to 63.20% in SIF were observed.