FORMULATION OF CURCUMIN NANOEMULSION FOR ENHANCED SOLUBILITY AND STABILITY

Abstract

Curcumin, a naturally occurring polyphenolic compound
derived from the rhizomes of Curcuma longa (turmeric),
has been widely investigated for its remarkable spectrum
of pharmacological activities encompassing antioxidant,
anti-inflammatory, antimicrobial, and anticancer properties. Despite its impressive bioactivity profile, the clinical
translation of curcumin remains substantially hampered
by its inherently poor aqueous solubility, rapid systemic
metabolism, photosensitivity, and consequent low oral
bioavailability. The present investigation was designed
to formulate and comprehensively evaluate a curcuminloaded nanoemulsion (NE) with the specific objective
of improving its aqueous solubility and physicochemical
stability. Curcumin NE was developed via spontaneous
emulsification complemented by high-speed homogenisation, employing oleic acid as the oil phase, Tween 80 as
the surfactant, and polyethylene glycol 400 (PEG 400)
as the co-surfactant. Six formulation batches (F1–F6)
were prepared by systematically varying the concentrations of oil, surfactant, and co-surfactant. The prepared
nanoemulsions were evaluated for physical appearance,
pH, viscosity, droplet size, polydispersity index (PDI),
zeta potential, percentage transmittance, drug content,
entrapment efficiency, and in-vitro drug release behaviour.
Thermodynamic stability testing was conducted through
centrifugation, heating–cooling cycles, and freeze–thaw cycles. Scanning Electron Microscopy (SEM) was employed
to characterise droplet morphology. The standard calibration curve of curcumin established in methanol at λmax of
425 nm yielded an excellent coefficient of determination
(R2 = 0.998). Drug content across formulations ranged
from 88.4% to 97.3%, confirming reproducible and uniform
drug incorporation. The optimised formulation displayed a
transparent, yellowish appearance with nanosized droplets,
minimal PDI, and satisfactory zeta potential, collectively
indicating enhanced physical stability. In-vitro drug release studies demonstrated markedly improved dissolution
of curcumin from the nanoemulsion relative to the pure
drug suspension. The developed formulation exhibited
superior aqueous dispersibility and protected curcumin
from environmental degradation. Collectively, these findings establish curcumin-loaded nanoemulsion as a highly
promising nanocarrier platform to overcome the inherent
biopharmaceutical limitations of curcumin and advance
its therapeutic utility.