Magnetic nanoparticle incorporated oleogel as iontophoretic drug delivery system.

In this article, we validated the use of electric current as an external stimulus to induce an enhancement of drug release from magnetic nanoparticle (MNP) incorporated organogels (magnetogel) under iontophoretic conditions. For this purpose, we adopted a simple, two-step synthesis route to incorporate magnetic (Fe3O4) nanoparticles (MNP) and ciprofloxacin hydrochloride within the network of a soybean oil-based oleogel using stearic acid as gelator. We fabricated a series of MNP incorporated oleogels by varying the wt% of MNPs while keeping a constant weight ratio of soybean oil:stearic acid. The microstructures of the magnetogels were analyzed in MNP concentration-dependent manner by optical microscopy, powder X-ray diffraction, FTIR, mechanical, and electrical studies. Detailed analysis of the electrical properties revealed that the gel sample with a maximum proportion of MNP (S4) allowed the maximum passage of current through it among all the compositions. Under the iontophoretic environment of the active condition, we observed nearly 2.5 fold increase in cumulative drug release in case of sample S4 compared to the corresponding passive condition. These observations suggested that in future, our magnetogel formulation can be further developed as AC field induced 'remote controlled' agent for therapeutic application.

Natural gum modified emulsion gel as single carrier for the oral delivery of probiotic-drug combination.

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.

Effect of mechanical and electrical behavior of gelatin hydrogels on drug release and cell proliferation.

The present study was aimed to explore the effect of the mechanical and the electrical properties of the gelatin hydrogels on the mammalian cell proliferation and drug release properties. FTIR analysis of the hydrogels suggested that gelatin retained its secondary protein structure. A decrease in the diffusion constant of the water molecules was observed with the increase in the gelatin concentration in the hydrogels. The mechanical and the electrical stabilities of the hydrogels were enhanced with the increase in the gelatin content. Stress relaxation and creep studies were modeled using Weichert and Burger׳s models, respectively. The relaxation time (stress relaxation study) did not follow a concentration-dependent relationship and was found to affect the MG-63 cell (human osteoblast) proliferation. The impedance profile of the hydrogels was modeled using a (RQ)Q model. Release of ciprofloxacin from the hydrogels was inversely dependent on the rate of swelling. The release of the drug was not only dependent on the Fickian diffusion but also on the relaxation process of the gelatin chains. The inhomogeneous constant of the constant phase element representing the hydrogel-electrode interface indicated improved cell proliferation rate with a decrease in the inhomogeneous constant. In gist, the rate of cell proliferation could be related to the relaxation time (stress relaxation) and the inhomogeneous constant of the sample-electrode constant phase element (electrical study) properties, whereas, the drug release properties can be related to the bulk resistance of the formulations.

Effect of Span 60 on the Microstructure, Crystallization Kinetics, and Mechanical Properties of Stearic Acid Oleogels: An In-Depth Analysis.

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.

Modulating the properties of sunflower oil based novel emulgels using castor oil fatty acid ester: prospects for topical antimicrobial drug delivery.

The current study describes the effect of polyglycerol polyricinoleate (PGPR) on the properties of sunflower oil and span-40 based emulgels. The prepared emulgels contained PGPR in varied concentrations. The microstructure of the emulgels was characterized by bright-field microscopy. The molecular interactions amongst the components of the emulgels were studied using FTIR spectroscopy. The flow and mechanical behaviors of the emulgels were studied using cone-and-plate viscometer and static mechanical tester, respectively. The efficiency of the metronidazole-loaded emulgels as antimicrobial formulations was tested in vitro. E. coli was used as the model microorganism for the antimicrobial study. The emulgels were also explored for iontophoretic delivery applications. The biocompatibility of the emulgels was tested using human keratinocytes (HaCaT). The microscopic evaluation of the emulgels indicated formation of biphasic formulations. FTIR studies suggested a decrease in the hydrogen bonding amongst the components of the emulgels as the concentration of the PGPR was increased. Viscosity studies indicated shear-thinning property of the emulgels. An increase in the PGPR concentration resulted in the reduction in the mechanical properties of the emulgels. Incorporation of PGPR resulted in the decrease in the drug released (both passive and iontophoresis) from the emulgels. The emulgels were found to be cytocompatible in the presence of keratinocytes. The drug loaded emulgels showed good antimicrobial activity against E. coli. In gist, the developed emulgels can be tried for controlled delivery of antimicrobial drugs. The physical and the release properties of the emulgels can be modulated by incorporating PGPR in varied proportions.