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The current study explores the properties of starch and non‐starch polysaccharides based bigels containing sunflower oil and their application in controlled delivery of metronidazole and probiotics. The bigels were prepared by mixing span‐40 and sunflower oil organogels with the aqueous polysaccharide sol. The microstructure of the bigels was characterized by fluorescent microscope. The bigels were then characterized for their mechanical properties using texture analysis. The flow behavior of the gels was studied using rheometer. The micrographs suggested uniform distribution of the organogels in the continuous aqueous phase. The bigels were viscoelastic in nature with a shear thinning behavior. The release of metronidazole from the bigels was diffusion mediated. These bigels showed good antimicrobial efficacy. The probiotics encapsulated within the bigels were tolerant to gastric and intestinal environment compared to the free cells. The preliminary studies suggest that the developed bigels can be used effectively for the delivery of poorly soluble drugs and probiotics.

The present work deals with preparation of the olive oil (OO) based organogels using sorbitan monostearate (SMS) and sorbitan monopalmitate (SMP) as organogelators for controlled drug delivery applications. Metronidazole (MZ) was used as the model drug. Gels were prepared by solubilizing the organogelators in OO at 60°C under stirring. As the solution was cooled down, the gelator molecules precipitate as an isotropic phase having networked structures, which immobilized OO. Formation of 3D networked structure was confirmed by light, phase contrast, and scanning electron microscopy. Accelerated thermal stability studies demonstrated the thermal stability and thermoreversibility of the organogels. DSC and gel disintegration studies suggested that the SMS based organogels were having higher thermal and physical strength as compared to the SMP based organogels. Viscometric analysis suggested the pseudoplastic flow behavior of the gels. The SMS organogels were more amorphous as compared to the SMP organogels of same composition. Drug release from the organogels followed Fickian diffusion kinetics. The drug loaded gels have shown good antimicrobial property against Escherichia coli and Bacillus subtilis and were found to be highly hemocompatible in nature. On the basis of the preliminary results, the developed organogels can be used as matrices for the topical drug delivery. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

The current study describes the preparation and characterization of thermoreversible span-60 and sunflower oil (SO)-based organogels as a matrix for drug delivery. Effect of gelator concentration on the properties of the organogels was studied by physical property evaluation, stability, light microscopy, FTIR spectroscopy, XRD, thermal analysis, pH, and hemocompatibility studies. The drug release kinetics and antimicrobial efficacy of the salicylic acid loaded organogels were studied. The rate of gelation of the gels was found to be quicker in organogels with higher gelator proportions. The gels were inherently stable when stored below 25 C. The micrographs indicated the presence of needle-shaped crystals which formed aggregates resulting in the formation of three-dimensional networked structures. FTIR indicated intermolecular hydrogen bonding amongst SO and span-60 molecules responsible for the gelation. There was an increase in the crystallinity and the melting point of the organogels as the proportion of the organogelator was increased. The pH of the organogels indicated nonirritant nature of the gels, which were also found to be hemocompatible. The release of SA from organogels followed Higuchian kinetics and showed prolonged antimicrobial activity. The preliminary results indicated that the organogels may be tried as a matrix for controlled drug delivery.

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