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Background: During the past few decades, the occurrence of superficial fungal infections has rapidly increased. As
the fungal infections take longer time to get cured, concepts such as designing drugs with extended persistence and
controlled release have gained attention. In this context, nanotechnology has been identified as the latest technological
revolution which has opened up new pathways for designing new therapeutic materials. Out of the many available
nano-structures layered double hydroxides have gained increased scientific attention in applications as slow and
controlled release drug formulations. This study focuses on the encapsulation of citric acid which has anti-fungal
properties into a Mg-Al- layered double hydroxide (LDH) in order to be used as slow release topical skin formulations.
Results: Citrate ions were encapsulated into Mg-Al LDH using one step co-precipitation reaction. The successful
intercalation of citrate ions into the layered structure has been proved referring to the expansion in the interlayer
spacing as observed by the shift in the basal peak of the powder X-ray diffraction pattern. Fourier transform infra-red
spectroscopy data suggests the change in the electron density around the carboxylate groups of the citrate ion thus
providing evidences for formation of encapsulated hybrid composite. The resulting nanohybrid has been then,
introduced into a general body cream formulation containing cocoa-butter. Both citrate LDH and the resulting
body cream formulations demonstrated prolonged slow release characteristics up to 8 h in aqueous medium
under different pH values (3, 4, and 5) compared to quick and fast release of pure citric acid. It was observed that
the slow reelase was most efficient at low pH values. The encapsulation between the nano-layers and citrate ions
are the key to the slow release characteristics. The body cream has been tested for the anti-fungal activity against
three common Candida species (C. albicans, C. glabrata, C. tropicalis). The novel nanohybrid has shown an improved
activity and slow release characteristics up to 48 h against the C. albicans and C. glabrata but not for C. tropicalis.
Conclusion: The study confirms that the citrate ion intercalated LDHs have the potential for use in future slow release
antifungal drug formulation.
