Supercritical Solvent Impregnation of Different Drugs in Mesoporous Nanostructured ZnO

Abstract

Supercritical solvent impregnation (SSI) is a green unconventional technique for preparing amorphous drug formulations. A mesoporous nanostructured ZnO (mesoNsZnO) carrier with 8-nm pores, spherical-nanoparticle morphology, and an SSA of 75 m2/g has been synthesized and, for the first time, subjected to SSI with poorly water-soluble drugs. Ibuprofen (IBU), clotrimazole (CTZ), and hydrocortisone (HC) were selected as highly, moderately, and poorly CO2-soluble drugs. Powder X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, nitrogen adsorption analysis, and ethanol extraction coupled with ultraviolet spectroscopy were employed to characterize the samples and quantify drug loading. Successful results were obtained with IBU and CTZ while HC loading was negligible, which could be related to different solubilities in CO2, drug size, and polarity. Successful SSI resulted in amorphous multilayer confinement of the drug. The mesoNsZnO-IBU system showed double drug loading than the mesoNsZnO-CTZ one, with a maximum uptake of 0.24 g/g. Variation of contact time during SSI of the mesoNsZnO-IBU system showed that drug loading triplicated between 3 and 8 h with an additional 30% increment between 8 h and 24 h. SSI did not affect the mesoNsZnO structure, and the presence of the adsorbed drug reduced the chemisorption of CO2 on the carrier surface.

Whey Proteins–Zinc Oxide Bionanocomposite as Antibacterial Films

“…The isotherm was type IV (IUPAC classification), revealing the presence of mesopores, most likely due to the interstices between the particles, as confirmed by FESEM images. These measurements confirm that the n-ZnO sample was similar to the one previously obtained [34] using methanol as solvent (SSA = 75 m 2 /g, particle size in the range 30-60 nm, hexagonal wurtzite-type phase), thereby showing that the same synthesis can be reproduced successfully in a greener and safer way by replacing methanol with ethanol.…”

Piroxicam Loading onto Mesoporous Silicas by Supercritical CO2 Impregnation

“…At the end of the loading process, 156 mg of PRX was theoretically added to the silica. Incorporation through scCO 2 was performed according to the procedure described elsewhere [ 38 ]. Briefly, a pellet of carrier (100 mg) and a pellet of piroxicam (100 mg) were placed in a glass cylinder and separated by a filter paper disc.…”

“…Briefly, a pellet of carrier (100 mg) and a pellet of piroxicam (100 mg) were placed in a glass cylinder and separated by a filter paper disc. The glass cylinder was introduced in a high-pressure vessel [ 27 , 38 ] where the impregnation took place in a static scCO 2 atmosphere at constant temperature (120 °C) and pressure (300 bar) for a fixed time (12 h). Temperature and pressure were selected according to a previous work [ 26 ] and taking into account that, when it is mixed with a carrier and contacted with scCO 2 , piroxicam may degrade at lower temperatures (120–150 °C) than its melting point (198–200 °C) [ 26 , 27 ].…”

A Review of Microwave Synthesis of Zinc Oxide Nanomaterials: Reactants, Process Parameters and Morphologies

“…It has been proved that ZnO NPs applied in textiles effectively fight bacteria, e.g., Staphylococcus aureus or Klebsiella pneumoniae [ 182 ]. In medicine, research is in progress on the application of ZnO NMs as a potential contrast agent (imaging), drug carrier, iron delivery, gene carrier, biosensor, a potential anti-cancer agent, in a photodynamic therapy, for prophylactic and therapeutic vaccines, support for antifungal treatments, in photocatalytic antibiotics, inhibition of influenza virus infection, diagnostic-therapeutic functions, wound dressing and tissue engineering [ 70 , 166 , 168 , 183 , 184 , 185 , 186 , 187 , 188 , 189 , 190 , 191 , 192 , 193 , 194 , 195 , 196 , 197 , 198 , 199 , 200 , 201 , 202 , 203 , 204 , 205 , 206 , 207 , 208 , 209 , 210 , 211 , 212 , 213 ]. However, before implementing ZnO NMs in biomedical applications on a commercial scale, the toxicity of ZnO NMs must be carefully learnt and their toxicity mechanisms must be explained [ 121 , 162 , 171 , 174 , 178 , ...…”