A rheological and microstructural characterisation of bigels for cosmetic and pharmaceutical uses.
Bigels are biphasic systems formed by water-based hydrogels and oil-based organogels, mainly studied, in the last few years, for pharmaceutical and cosmetic application focused on the controlled delivery of both lipophilic and hydrophilic active agents. The rheological properties of bigels depend on both the amount and the rheological characteristics of single structured phases. Moreover, it can be expected that, at large fractions of one of the starting gels, systems more complex than oil-in-water or water-in-oil can be obtained, yielding bicontinuous or matrix-in-matrix arrangement. Model bigels were investigated from a microstructural (i.e. microscopy and electrical conductivity tests) and rheological point of view. The hydrogel was prepared by using a low-methoxyl pectin whereas the organogel was prepared by using olive oil and, as gelator, a mixture of glyceryl stearate and policosanol. Model bigels were obtained by increasing the amount of organogel mixed with the hydrogel, and microstructural characterisation evidenced an organogel-in-hydrogel behaviour for all investigated samples, even though at the highest organogel content a more complex structure seems to arise. A semi-empirical model, based on theoretical equations developed for suspensions of elastic spheres in elastic media, was proposed to relate bigel rheological properties to single phase properties and fractions.
Department of Information, Modeling, Electronics and System Engineering, (D.I.M.E.S.), University of Calabria, Via P. Bucci, Cubo 39C, I-87036, Rende, CS, Italy. Electronic address: francesca.lupi@unical.it.
Francesca R
FR
Lupi
Department of Information, Modeling, Electronics and System Engineering, (D.I.M.E.S.), University of Calabria, Via P. Bucci, Cubo 39C, I-87036, Rende, CS, Italy. Electronic address: ahmad_farooqi@hotmail.com.
Ahmad
A
Shakeel
Department of Information, Modeling, Electronics and System Engineering, (D.I.M.E.S.), University of Calabria, Via P. Bucci, Cubo 39C, I-87036, Rende, CS, Italy. Electronic address: valeria.greco@unical.it.
Valeria
V
Greco
Department of Chemistry and Chemical Technologies, University of Calabria, Via P. Bucci, Cubo 14D, I-87036 Rende, CS, Italy. Electronic address: cesare.oliviero@unical.it.
Cesare
C
Oliviero Rossi
Department of Information, Modeling, Electronics and System Engineering, (D.I.M.E.S.), University of Calabria, Via P. Bucci, Cubo 39C, I-87036, Rende, CS, Italy. Electronic address: noemi.baldino@unical.it.
Noemi
N
Baldino
Department of Information, Modeling, Electronics and System Engineering, (D.I.M.E.S.), University of Calabria, Via P. Bucci, Cubo 39C, I-87036, Rende, CS, Italy. Electronic address: domenico.gabriele@unical.it.
Domenico
D
Gabriele
D003358:Cosmetics / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry; D004553:Electric Conductivity; D020100:Hydrogels / Q000737:chemistry*; D008853:Microscopy; D000069463:Olive Oil / Q000737:chemistry; D010316:Particle Size; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D012212:Rheology; D013696:Temperature
D003358:Cosmetics; D004337:Drug Carriers; D020100:Hydrogels; D000069463:Olive Oil; D004364:Pharmaceutical Preparations
Bigel; Cosmetics; Hydrogel; Olive oil; Organogel; Rheology