Comparison of the crystal structures and physicochemical properties of novel resveratrol cocrystals

A drug-drug cocrystal and a co-amorphous form, prepared from honokiol and ligustrazine, inspired by Chinese patent medicine

A drug-drug cocrystal created with two antithrombotic-active ingredients from herbs, honokiol (HON) and ligustrazine (TMP, 1:1), was synthesized and characterized. The structure of HON-TMP (1:1) was determined by single-crystal X-ray diffraction. Then co-amorphous HON-TMP was prepared by honey-assisted grinding, which was inspired by a grinding process for a Chinese patent medicine-Shijunzi honey pill. This co-amorphous drug-drug cocrystal (20% honey) exhibits improved solubility over HON and a significantly reduced sublimation tendency than TMP.

Permeability of antioxidants through a lipid bilayer model with coarse-grained simulations

Oxidative stress caused by pollution and lifestyle changes causes an excess of free radicals that react chemically with cell constituents leading to irreversible damage. There are molecules known as antioxidants that reduce the levels of free radicals. Some pigments of fruits and vegetables known as anthocyanins have antioxidant properties. Their interaction with the cell membrane becomes a crucial step in studying these substances. In this research, molecular dynamics simulations, particularly, coarse-grained molecular dynamics (CGMD) were used. This technique aims to replace functional groups with corresponding beads that represent their level of polarity and affinities to other chemical groups. Also, umbrella sampling was carried out to obtain free energy profiles that describe well the orientation and location of antioxidants in a membrane considering Trolox, Cyanidin, Gallic Acid, and Resveratrol molecules to study the structural effects they cause on it. It was concluded in this study that an antioxidant when crossing the membrane does not cause either damage to the structural properties or the loss of packing and stratification of phospholipids. it was also observed that the most reactive part of the molecules could easily approach area A prone to lipid oxidation, which can describe the antioxidant capacity of these molecules.Communicated by Ramaswamy H. Sarma.

A novel fixed-combination timolol-netarsudil-latanoprost ophthalmic solution for the treatment of glaucoma and ocular hypertension

Currently commercial fixed-concomitant three agents have multiple problems such as multiple dosing administration, poor efficacy and side effects. Once-daily fixed-combination timolol-netarsudil-latanoprost ophthalmic solution (FC-TNL) has the ability to treat glaucoma by lowering the intraocular pressure (IOP) with great efficacy and improving patient compliance. However, the commercialized netarsudil dimesylate precipitated when the pH of the solution was above 5.4, or when maleic acid, the salt of commercial timolol maleate, was mixed with netarsudil dimesylate. Consequently, the homologous salt engineering strategy was used to make netarsudil dimesylate soluble in pH 4.8-5.2 solution by synthesizing timolol mesylate. Next, the morphology of timolol mesylate was observed by scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and powder X-ray diffraction. The prepared FC-TNL showed good stability during refrigeration storage. Additionally, FC-TNL exerted no influence on the intraocular penetration of each active compounds in the pharmacokinetic study. Importantly, once-daily FC-TNL exerted potent IOP-lowering effect and protective effect on retinal ganglion cells. The FC-TNL was stable, safe and effective, being a promising glaucoma therapeutic.

Weak intermolecular interactions in a series of biologically active 4′-methylthio-trans-stilbenes

The crystal structures of nine methoxy-substituted 4′-methylthiostilbenes, which are potential inhibitors of human recombinant cytochrome P450 enzymes, were determined. These compounds included two mono-methoxy-substituted derivatives: 2-methoxy-4′-methylthio-trans-stilbene {systematic name: 1-[(E)-2-(2-methoxyphenyl)ethenyl]-4-(methylsulfanyl)benzene} (1) and 3-methoxy-4′-methylthio-trans-stilbene (2), both C16H16OS; four dimethoxy derivatives: 2,3-dimethoxy-4′-methylthio-trans-stilbene (3), 2,5-dimethoxy-4′-methylthio-trans-stilbene (4), 3,5-dimethoxy-4′-methylthio-trans-stilbene (5) and 2,4-dimethoxy-4′-methylthio-trans-stilbene (6), all C17H18O2S; and three trimethoxy compounds: 2,4,5-trimethoxy-4′-methylthio-trans-stilbene (7), 3,4,5-trimethoxy-4′-methylthio-trans-stilbene (8) and 2,4,6-trimethoxy-4′-methylthio-trans-stilbene (9), all C18H20O3S. The geometries of the compounds in the crystal structures were compared with those found during docking studies at the active site of the receptor, and some relevant differences were identified. Intermolecular interactions were analyzed using three different methods. First, the (3,−1) critical points of the gradient field of the electron density were identified, and then the appropriate contacts were analyzed using their geometrical characteristics and interaction energy calculations. The results confirmed the importance of weak delocalized interactions in the construction of the crystal structures, and the results of different methods (PIXEL and DFT) were comparable in the absence of strong well-defined intermolecular interactions.

Cocrystals/salt of 1-naphthaleneacetic acid and utilizing Hirshfeld surface calculations for acid–aminopyrimidine synthons

Revisit of acid–aminopyrimidine synthons to explore the robustness in presence of linear hetrotetramer and heterotrimer synthon.