Rungphanichkul et al. showed that curcuminoids can be
successfully formulated as niosomes by series of Span nonionic
surfactants to enhance the skin permeation of curcuminoids
and improve its properties for transdermal delivery [74]. Liu
and Chang developed aneucalyptol microemulsion system as a
promising tool for the percutaneous delivery of curcumin [75].
Microemulsions have been extensively studied for the applications
in transdermal drug delivery. The solubility of curcumin
in various oils, surfactants, and cosurfactants were studied to
find the optimal components for a transdermal delivery vehicle
and microemulsions were successfully developed for transdermal
curcumin delivery after screening various components
and adjusting the oil/water ratios [75]. Microemulsions loaded
with curcumin were successfully optimized for transdermal
delivery after screening various terpenes, cosurfactants, and
limonene/water ratios, and it was found out that the limonene
microemulsion system is a promising tool for the percutaneous
delivery of curcumin [76]. Further, Chaudhary et al. developed
and optimized a transdermal gel formulation for diclofenacdiethylamine
and curcumin. They successfully showed that permeation
rate of diclofenacdiethylamine decreased with polymer
concentration, whereas the permeation rate of curcumin
increased proportionally with polymer concentration [77]. Patel
et al. developed and studied the topical gel delivery of curcumin
for its anti-inflammatory effects and showed that Carbopol
934P gel showed better inhibition of inflammation [78]. There is
very little knowledge about the localization of the drugs within
the skin and the stratum corneum. Teichmann et al. showed
that lipophilic dye curcumin incorporated in an oil-in-water
microemulsion and as an amphiphilic cream was applied onto
the skin and a deeper part of the stratum corneum was accessible
and significantly smaller amounts of curcumin was found
on the skin surface [79]. Furthermore, curcumin was detected
in hair follicles, so it is obvious that the microemulsion led to a
penetration into the complete follicular infundibula [79]. An in
vivo animal study by Dai et al. demonstrated that sponge has
better effect than cotton gauze, and adding curcumin into the
sponge enhanced the therapeutic healing effect [80]. A biodegradable
sponge, composed of chitosan and sodium alginate,
was successfully obtained and swelling ability, in vitro drug
release and degradation behaviors, and an in vivo animal test
were used to confirm the applicability of this sponge as a
wound dressing material. The release of curcumin from the
sponges could be controlled by the cross linking degree [80].
The study by Thangapazham et al. [81] showed the enhancement
of targeted delivery of an anticancer agent, curcumin, for
cancer treatment by incorporating this agent into the liposomes
(nanodelivery vehicles primarily composed of phospholipids).
They prepared curcumin-loaded liposomes of various lipid compositions
by sonication and considered the use of liposomes as
a delivery model for curcumin [81]. The cell proliferation assays
provide strong evidence for liposomes as effective nanodelivery
vehicles that increase the bioavailability of curcumin [81].