Enhancing the water solubility of curcumin by encapsulating in Carrageenan using excipients

Abstract

Curcumin is a polyphenolic compound known to alleviate several ailments and can be used as a drug. However, its practical application as a nutraceutical/drug is limited due to problems such as high hydrophobicity, high photosensitivity, and low bioavailability. Therefore, encapsulation of curcumin into nanoparticle (NP) carriers has been developed to increase the aqueous (physiological) solubility of curcumin. Carrageenan, a natural polysaccharide, is widely used in the formulation of nanoparticles as a controlled-release drug delivery system. In this study, a water-soluble product was developed by encapsulating curcumin in a carrageenan matrix using surfactant excipients (Tween 20 & Tween 80). Encapsulation provides protection to drugs against physiological degradation and ensures effective release at targeted sites. The role of the surfactant excipients is to help increase the water solubility and the stability of the particles. Curcumin-encapsulated carrageenan nanoparticles were prepared via the ionic gelation method, varying the mass of the curcumin, the mass of the carrageenan, and the type of excipient used. A water solubility test for NPs was conducted to evaluate the solubility of NPs in water. The average particle sizes of the NPs were obtained as 470.4 nm. The highest encapsulation efficiency of curcumin-encapsulated carrageenan NPs was calculated as 90% for NPs prepared using both excipients. In-vitro release studies were performed on the drug-loaded NPs and the results showed that the release was pH dependant and had a high release (50%-60%) of curcumin in intestinal fluid compared to free curcumin. Confirmation of successful encapsulation and characterisation of the curcumin-encapsulated carrageenan NPs was carried out using fourier transform infrared spectroscopy (FTIR) analysis. The stability of the NPs against photodegradation and thermal degradation was checked using the accelerated shelf life method. Scanning electron microscope (SEM) images of both nanoparticles prepared using both excipients displayed a nearly spherical shape. These empirical data proved that newly formulated NPs could preserve the activities of curcumin and hence could be used in functional food production to increase the nutritional value without changing texture and colour. Also, this study successfully demonstrated that even though the hydrophilic–lipophilic balance (HLB) values of tween 20 (16.7) and tween 80 (15.0) are different, both are equally effective in enhancing the solubility, encapsulation efficiency, and stability of curcumin-loaded carrageenan NPs. Future studies could investigate the scalability of the nanoparticle formulation process for industrial applications and explore the potential of combining these NPs with other bioactive compounds to develop multifunctional delivery systems.