Effect of hydrophobic moiety on the gelation behavior of pyridyl boronic acid-derived amphiphiles: application in entrapment and release of vitamin B12

Low molecular weight organic gelators (LMOGs) have received great attention for their tremendous applications in multiple fields in the past few decades. Therefore, nowadays, synthesis of new type of LMOGs is a demanding field of research. In this work, the effect of hydrophobic moiety on gelation behavior of three synthesized pyridyl boronic acid-derived amphiphiles named sodium, 2-decylpyridine-5-boronate (SDPB), sodium, 2-oxydecylpyridine-5-boronate (SODPB) and sodium, 2-oxydodecylpyridine-5-boronate (SODDPB) has been investigated. The results confirmed that these amphiphiles are good gelators in common organic solvents in the presence of 60 μl of buffer solution and the gelation capability diminished in case of oxygen atom present in the alkyl chain. Further distortion of gelation process was observed with increase of chain length in oxy-alkyl chain. Rheological measurements established that the gel emulsion of SDPB is most stable towards external forces with highest elasticity value. XRD study was performed to analyze the orientation of the alkyl chain in the 3D network structure in the gel emulsions. The morphological changes with respect to concentration were investigated by FE-SEM study of the gel emulsions. The prepared gel emulsions with these amphiphiles are capable to entrap and release the biomolecule vitamin B 12 at room temperature keeping the structure and activity unchanged which is indicative that the amphiphiles can be successfully utilized in pharmaceutical industries as drug delivery vehicles. Highlights Efficient single-chain pyridyl boronic acid gelators of organic solvents and mineral oils. Decrease in gelation ability by the introduction of ether linkage in the hydrophobic part. Concentration-dependent morphology change was observed. Entrapment and release of biomolecule at room temperature. Graphic abstract