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The present study describes the encapsulation of vegetable fats (cocoa butter and mango butter) within chitosan microparticles by double emulsion technique to prevent leaching of the internal apolar phase. Leaching studies suggested negligible leaching of the internal phase (∼12–14%) when the fats were encapsulated as compared to the control (∼40%). Fourier transform infrared spectroscopy and differential scanning calorimeter studies confirmed the successful encapsulation of fats. The release of drug (ciprofloxacin) from the microparticles was diffusion and erosion mediated and were capable to elicit antimicrobial activity againstEscherichia coli. The study suggests that the developed microparticles have the potential for controlled delivery of antimicrobials. [ABSTRACT FROM PUBLISHER]

Modulation of crystallization of stearic acid and its derivatives is important for tuning the properties of stearate oleogels. The present study delineates the crystallization of stearic acid in stearate oleogels in the presence of Span 60. Microarchitecture analysis revealed that stearic acid crystals in the oleogels changed its shape from plate-like structure to a branched architecture in the presence of Span 60. Consequently, a significant variation in the mobility of the solute molecules inside the oleogel (Fluorescence recovery after photobleaching studies, FRAP analysis) was observed. Thermal analysis (gelation kinetics and DSC) revealed shortening of nucleation induction time and secondary crystallization with an increase in the Span 60 concentration. Furthermore, isosolid diagram suggested better physical stability of the formulations at higher proportions of Span 60. XRD analysis indicated that there was a decrease in the crystal size and the crystallinity of the stearic acid crystals with an increase in Span 60 concentration in the Span 60 containing oleogels. However, crystal growth orientation was unidirectional and found unaltered with Span 60 concentration (Avarmi analysis using DSC data). The mechanical study indicated a composition-dependent variation in the viscoelastic properties (instantaneous [τ1], intermediate [τ2], and delayed [τ3] relaxation times) of the formulations. In conclusion, Span 60 can be used to alter the kinetics of the crystallization, crystal habit and crystal structure of stearic acid. This study provides a number of clues that could be used further for developing oleogel based formulation. [ABSTRACT FROM AUTHOR]

In this study, we dealt with the development of lecithin-based organogels using sunflower oil as the apolar phase. Metronidazole (MZ) was used as a model drug. The organogels were characterized by microscopy (light and phase contrast), Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, rheology, alternating-current impedance, hemocompatibility, antimicrobial analysis, and in vitro drug release. Microscopic analysis revealed the presence of spherical reverse micellar structures. There was an increase in the intermolecular hydrogen bonding among the gel components and crystallinity as MZ was incorporated into the organogels. The pH of the gel indicated that the gel may be nonirritant in nature and was hemocompatible. The release of MZ from the organogels followed Higuchi kinetics and was governed by anomalous or non-Fickian transport. The drug-loaded organogels showed antimicrobial activity against Bacillus subtilis, a Gram-positive bacteria. The preliminary results indicate that the developed organogel may be used as drug-delivery vehicle. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

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. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

Single formulation based delivery of probiotic-drug combination is envisioned as a superior therapeutic delivery modality for the diseases like Crohn's diseases, ulceritive colitis and Recurrent Clostridium difficile-Associated Diarrhoea (RCDAD). Keeping this perspective in mind, here we have developed natural gum [using a combination of aqueous solution of xantham gum (X) and guar gum (G)] modified sunflower oil based emulsion gels for the delivery of probiotics-drugs combination. FT-IR analysis and fluorescence microscopy together confirmed the formation of oil-in-water type emulsion gel by physical gelation in presence of the physical gelator sorbitan monopalmitate (SM). Other studies (XRD, DSC, mechanical properties and disintegration study) revealed that the variation in relative proportion of the two gums has a sporadic but significant effect on the physico-chemical properties of the gel. Post storage viability of commercially used probiotic Lactobacillus plantarum 299v (Lp 299v) at different storage conditions (4°C, -20°C, -196°C) was found higher in the emulsion gels with respect to the control. Moreover, the gels were found suitable for sustained delivery of metronidazole (the lipophilic drug often used with Lp 299v). In conclusion, the natural gum modified emulsion gel may be used as a delivery system for the probiotic-drug combination., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Stearic acid and its derivatives have been used as gelators in food and pharmaceutical gel formulations. However, the mechanism pertaining to the stearic acid based gelation has not been deciphered yet. Keeping that in mind, we investigated the role of stearic acid on physic-chemical properties of oleogel. For this purpose, two different oil (sesame oil and soy bean oil) formulations/oleogels were prepared. In depth analysis of gel kinetics, gel microstructure, molecular interactions, thermal and mechanical behaviors of the oleogels were done. The properties of the oleogels were dependent on the type of the vegetable oil used and the concentration of the stearic acid. Avrami analysis of DSC thermograms indicated that heterogeneous nucleation was coupled with the one-dimensional growth of gelator fibers as the key phenomenon in the formation of oleogels. Viscoelastic and pseudoplastic nature of the oleogels was analyzed in-depth by fitting the stress relaxation data in modified Peleg's model and rheological studies, respectively. Textural studies have revealed that the coexistence of hydrogen bond dissipation and formation of new bonds is possible under stress conditions in the physical oleogels., (Copyright © 2014 Elsevier B.V. All rights reserved.)