Mode of binding, kinetic and thermodynamic properties of a lipid-like drug (Fingolimod) interacting with Human Serum Albumin.

Introduction: Fingolimod is a drug that is used to treat multiple sclerosis (MS). It has pH-dependent solubility and low solubility when buffering agents are present. Multi-spectroscopic and molecular modeling methods were used to investigate the molecular mechanism of Fingolimod interaction with human serum albumin (HSA), and the resulting data were fitted to the appropriate models to investigate the molecular mechanism of interaction, binding constant, and thermodynamic properties. Methods: The interaction of Fingolimod with HSA was investigated in a NaCl aqueous solution (0.1 mM). The working solutions had a pH of 6.5. Data was collected using UV-vis, fluorescence quenching titrations, FTIR, and molecular modeling methods. Results: According to the results of the fluorescence quenching titrations, the quenching mechanism is static. The apparent binding constant value (KA = 4.26×103) showed that Fingolimod is a moderate HSA binder. The reduction of the KA at higher temperatures could be a result of protein unfolding. Hydrogen bonding and van der Waals interactions are the main contributors to Fingolimod-HSA complex formation. FTIR and CD characterizations suggested a slight decrease in the α-helix and ß-sheets of the secondary structure of HSA due to Fingolimod binding. Fingolimod binds to the binding site II, while a smaller tendency to the binding site I was observed as well. The results of the site marker competitive experiment and the thermodynamic studies agreed with the results of the molecular docking. Conclusion: The pharmacokinetic properties of fingolimod can be influenced by its HSA binding. In addition, considering its mild interaction, site II binding drugs are likely to compete. The methodology described here may be used to investigate the molecular mechanism of HSA interaction with lipid-like drugs with low aqueous solubility or pH-dependent solubility.

3-(Amino-carbon-yl)pyridinium diaqua-bis-(pyridine-2,6-dicarboxyl-ato)bis-muthate(III) monohydrate.

The asymmetric unit of the ionic title compound, (C(6)H(7)N(2)O)[Bi(C(7)H(3)NO(4))(2)(H(2)O)(2)]·H(2)O or (acpyH)[Bi(pydc)(2)(H(2)O)(2)]·H(2)O, contains an [Bi(pydc)(2)(H(2)O)(2)](-) anion (where pydcH(2) is pyridine-2,6-dicarb-oxy-lic acid), a protonated 3-(amino-carbon-yl)pyridine as counter-ion, (acpyH)(+), and one uncoordinated water mol-ecule. The anion is an eight-coordinate complex with a square-anti-prismatic geometry around the Bi(III) atom. In the crystal, extensive O-H⋯O and N-H⋯O hydrogen bonds, as well as ion pairing, C=O⋯π inter-actions [O⋯centroid distance = 3.583 (5) Å], π-π stacking [centroid-centroid distance = 3.864 (3) Å], and C-H⋯π and C-H⋯O inter-actions, play an important role in the formation and stabilization of the three-dimensional supra-molecular structure.

Pregnancy outcomes following the administration of high doses of dexamethasone in early pregnancy.

OBJECTIVE: In the present study, we aimed to evaluate the effects of high doses of dexamethasone (DEX) in early pregnancy on pregnancy outcomes. METHODS: Pregnant BALB/c mice were treated with high-dose DEX in the experimental group or saline in the control group on gestational days (GDs) 0.5 to 4.5. Pregnant mice were sacrificed on GDs 7.5, 13.5, or 18.5 and their peripheral blood, placentas, fetuses, and uterine tissue were collected. Decidual and placenta cell supernatants were examined to evaluate the effect of DEX on the proliferation of mononuclear cells, the quantity of uterine macrophages and uterine natural killer (uNK) cells, and levels of progesterone and 17ß-estradiol, as determined by an 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide assay, immunohistochemistry, and enzyme-linked immunosorbent assay, respectively. We also were measured fetal and placental growth parameters on GD 18.5. RESULTS: We found that high doses of DEX were associated with an increased abortion rate, enhancement of the immunosuppressive effect of the decidua, alterations in placental growth parameters, decreased progesterone and 17ß-estradiol levels, and a reduced frequency of macrophages and uNK cells. CONCLUSION: Our data suggest that the high-dose administration of DEX during early pregnancy negatively affected pregnancy outcomes.