Development of curcumin formulations with enhanced bioavailability for oral drug delivery

[Speaker] Yishan Zheng:1
[Co-author] Ananth Pannala:1, Tu Duong Ngoc:2, John Smart:1
1:School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, BN2 4GJ, United Kingdom, UK, 2:Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Street, Hanoi, Viet Nam

Curcumin, extracted from the spice turmeric is commonly used in traditional Chinese and Indian medicine, has attracted increased interest for treating chronic inflammatory diseases owing to its antioxidant and anti-inflammatory properties. It has been reported that curcumin scavenges free radicals and their reactive metabolites due to its antioxidant activity, and blocks the free radical mediated inflammatory responses resulting in its anti-inflammatory activity. However, it has limited medical use due to its low oral bioavailability largely attributed to its low aqueous solubility. Its low intestinal adsorption is exacerbated by its rapid metabolism and excretion. Several approaches including the use of emulsions, micro-/nano-crystallised formulations, liposomes, cyclodextrin-complexes, conjugation with water soluble polymers, self-assembled particles and nanogels have been proposed to improve the oral bioavailability of curcumin. However, these approaches are difficult to manufacture in a large scale and require expensive machinery. The approach in the current work is to develop a cost-effective and scalable solid oral formulation of curcumin with enhanced bioavailability using water soluble polymers.
Curcumin formulations were prepared through melt-granulation process. Curcumin was dissolved in polyethylene glycol (PEG) and PEG-block copolymer. A series of curcumin to PEG and PEG-block copolymer compositions were tested to maximise curcumin aqueous solubility. Loading of different curcuminoids in the formulation and their aqueous solubility was determined using HPLC along with their dissolution profile. The observations from the new curcumin formulations were compared to a commercially available curcumin product.
Dissolving curcumin in PEG can ensure its dispersion at molecular level in aqueous environments, the addition of PEG-bloc-copolymer can further stabilise this dispersion thus, resulted in the increased curcumin aqueous solubility. The results demonstrated that the new formulation can deliver 60mg of curcumin per capsule and showed faster and higher rate of release of curcumin in the soluble form both in simulated gastric conditions and intestinal conditions compared to the commercial comparator.
The formulations showed enhanced dissolution and were relatively simple to produce. The PEG-block copolymer increased curcumin aqueous solubility by forming a water soluble complex with the drug. Future work involving in vivo supplementation studies are required to confirm these in vitro observations.

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