Effect of pH and amphiphile concentration on the gel-emulsion of sodium salt of 2-dodecylpyridine-5-boronic acid: Entrapment and release of vitamin B_(12)

摘要

Hypothesis: Single chain pyridyl boronic acid based amphiphilic gelator, sodium salt of 2-dodecylpyridine- 5-boronic acid (SDDPB) spontaneously form emulsified morphology at buffer solutions of two different pHs at low amphiphile concentration whereas closed morphology at higher concentration in presence of fructose. Retention of structure and activity of released biomolecule at room temperature has promising prospect in the pharmaceutical industry. Experimental: The gel-emulsions were studied by XRD, Rheology, DSC, optical microscopy, FESEM, AFM and UV-vis spectroscopy. Findings: XRD study indicates presence of two recognizable morphologies of the amphiphile at pH 9 whereas at pH 13 a single type of aggregate has predominant. Rheological measurements prove mechanical stability and viscoelasticity of the gel-emulsions. FESEM images of xerogels at both pHs and at low concentration of the amphiphile establish the presence of network morphology; whereas at high concentration the xerogel at pH 9 exhibit both network and rhombic structure and at pH 13 only closed structure was observed. AFM measurement at high concentration also confirms the same observation. The gel-emulsions were used in the controlled and/or pH triggered release of entrapped vitamin B12 at two different pHs.