Facile, low-cost, and organic-free fabrication of diverse nanoporous alumina as support for drug release; on the salt effect, calcination temperature, and reaction time dependence

In a new perspective for the formulation and release of the poorly soluble drugs, γ-alumina with the variety of pore architecture was synthesized via a facile and non-expensive route without using any organic moieties or solvents, only by changing the synthetic variables such as: type of counter ion (nitrate and sulfate), calcination temperature (500 and 800 °C), and the rate of adding the precipitating agent (2 and 7 h or fast and slow). With this regard, the samples were denoted as AlN-Fa(500), AlN-Sl(500), AlS-Fa(500), AlS-Sl(500), AlN-Fa(800), AlN-Sl(800), AlS-Fa(800), AlS-Sl(800). These synthesized nanoporous alumina were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, N₂ adsorption-desorption isotherms (Brunauer–Emmett–Teller-Barrete–Joynere–Halenda), field-emission scanning electron microscope, and zeta potential instrumentation techniques. Synthetic parameters led to the nanoporous alumina with surface areas between 34 and 203 m²/g, pore sizes in the range of 4–45 nm, positive and negative zeta potential charge, as well as different structural morphologies. These miscellaneous porosities were used as support for nifedipine drug in order to increase the release of this insoluble drug in simulated gastric fluid and intestinal fluid. These conditions led to the eight different release profiles. AlN-Fa(500)@Nif nanodrug, as the best case, indicated 100% sustained release after 13 h of soaking time in simulated intestinal fluid. Finally, the potential of the mentioned formulation in protecting SH-SY5Y cells were tested from oxidative stress caused by parkinsonian toxin 6-OHDA and found that the formulation neutralizes 6-OHDA toxicity and significantly enhances cell survival.