Parfenyuk et al. [21] have demonstrated the SC79 possibility of the application of silica nanoparticles for topical delivery of the immunomodulatory drug glucosaminylmuramyl
dipeptide (GMDP; the chemically synthesized natural equivalent of peptidoglycan) to the peritoneal macrophages of women with endometriosis. Researchers have shown that the immunomodulatory effect of GMDP can be increased by its immobilization on silica nanoparticles. The aim of this study was to examine chemical transformations of thiophenylglycoside of MDP with silica Quisinostat surface and to characterize the structure of the adsorbed films on silica by temperature-programmed desorption mass spectrometry (TPD-MS) and Fourier transform infrared spectroscopy (FTIR). Methods Materials Powdery fumed silica (pilot plant at the Institute of the Surface Chemistry, Kalush, Ukraine; with a specific
surface area of 270 m2/g) was used in this work. Fumed silica was previously heated on air for ACY-738 ic50 2 h at 400°С to remove adsorbed organic substances. Benzyl ester of О-(phenyl-2-acetamido-2,3-dideoxy-1-thio-β-D-glucopyranoside-3-yl)-D-lactoyl-L-alanyl-D-isoglutamine (SPhMDPOBn; Figure 1) was synthesized at the Department of Biological and Organic Chemistry of Taurida National V.I. Vernadsky University: SPhMDPOBn 1H-NMR (DMSO-d6) SAr: 7.11 to 7.24 (m, CHar); GlcNac: 4.75 (d, 1 H, J = 10 Hz), 1.79 (s, NAc), 7.98 (d, NHAc), 5.58 (d, C4-OH), 4.69 (bt, C6-OH);
1.25 (d, CH3CHCO); Ala: 1.25 (d, CH3), 7.11 to 7.24 (m, NH); Glu: 12.48 (bs, CO2R), 2.10 (t, γ-CH2), 1.74, 1.95 (m, β-CH2), 6.79, 7.24 (s, CONH2), 8.28 (d, NH) [22]. Figure 1 Structure of О -(phenyl-2-acetamido-2,3-dideoxy-1-thio-β- d -glucopyranoside-3-yl)- d -lactoyl- l -alanyl- d -isoglutamine (SPhMDPOBn). The details of the synthesis procedure of SPhMDPOBn have been previously reported [22]. Loading of MDP arylthioglycosides GPX6 on the fumed silica surface The sample of SPhMDPOBn with a concentration of 0.6 mmol/g on the silica surface was obtained by impregnation. It is known that the concentration of free silanol groups (isolated ≡ Si-OH groups), the main active sites, on the silica surface is equal to 0.6 mmol/g of silica [23]. The weight of the MDP thioglycoside batch was such as to ensure a ratio of the concentration of modifier to that of silica surface silanol groups of 1:1. A 0.0121 g of SPhMDPOBn dissolved in 0.8 mL of 96% ethanol was added to 0.03 g of fumed silica in a Petri dish. The components were mixed and left on air at approximately 20°C till the solvent is evaporated (approximately 12 h). In the experiment, the air-dried sample was under investigation.