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14 pages, 1762 KiB

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Supramolecular Organization in Salts of Riluzole with Dihydroxybenzoic Acids—The Key Role of the Mutual Arrangement of OH Groups

by Alexander P. Voronin, Artem O. Surov, Andrei V. Churakov and Mikhail V. Vener

Pharmaceutics 2023, 15(3), 878; https://doi.org/10.3390/pharmaceutics15030878 - 8 Mar 2023

Cited by 9 | Viewed by 2275

Abstract

Intermolecular interactions, in particular hydrogen bonds, play a key role in crystal engineering. The ability to form hydrogen bonds of various types and strengths causes competition between supramolecular synthons in pharmaceutical multicomponent crystals. In this work, we investigate the influence of positional isomerism on the packing arrangements and the network of hydrogen bonds in multicomponent crystals of the drug riluzole with hydroxyl derivatives of salicylic acid. The supramolecular organization of the riluzole salt containing 2,6-dihydroxybenzoic acid differs from that of the solid forms with 2,4- and 2,5-dihydroxybenzoic acids. Because the second OH group is not at position 6 in the latter crystals, intermolecular charge-assisted hydrogen bonds are formed. According to periodic DFT calculations, the enthalpy of these H-bonds exceeds 30 kJ·mol⁻¹. The positional isomerism appears to have little effect on the enthalpy of the primary supramolecular synthon (65–70 kJ·mol⁻¹), but it does result in the formation of a two-dimensional network of hydrogen bonds and an increase in the overall lattice energy. According to the results of the present study, 2,6-dihydroxybenzoic acid can be treated as a promising counterion for the design of pharmaceutical multicomponent crystals. Full article

(This article belongs to the Special Issue New Properties of Supramolecular Complexes and Drug Nanoparticles)

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14 pages, 3333 KiB

Open AccessArticle

Stabilization of Acne Vulgaris-Associated Microbial Dysbiosis with 2% Supramolecular Salicylic Acid

by Hazrat Bilal, Yuanyuan Xiao, Muhammad Nadeem Khan, Jinyu Chen, Qian Wang, Yuebin Zeng and Xinyu Lin

Pharmaceuticals 2023, 16(1), 87; https://doi.org/10.3390/ph16010087 - 8 Jan 2023

Cited by 16 | Viewed by 6920

Abstract

Facial microbiota dysbiosis is an important factor in causing acne vulgaris. The present study aimed to analyze the effect of 2% Supramolecular Salicylic Acid (SSA) on acne-associated facial bacteria. In the current study, 30 acne vulgaris patients (treated with 2% SSA for eight weeks) and ten volunteers with no facial acne were selected. Samples from acne patients (before and after treatment) and volunteers (not treated) were analyzed via high throughput sequencing, Deblur algorithm, and R microbiome package. After treatment with 2% SSA, the total lesion count and global acne grading system (GAGS) score reduced significantly (p < 0.001). Metagenomic sequencing analysis revealed that the pre-treated acne group had low α and deviated β diversity compared to the control and post-treated acne groups. Due to the treatment with 2% SSA, α diversity index was increased and β diversity was stabilized significantly (p < 0.001). The relative abundance of bacterial genera in the pre-treated acne group was uneven and had a high proportion of Staphylococcus, Ralstonia, and Streptococcus. The proportion of these three genera was significantly decreased in the post-treated group, and overall bacteria genera distribution tends toward the healthy individual. It is concluded that 2% SSA normalizes the microbial communities associated with the skin. Full article

(This article belongs to the Topic Compounds with Medicinal Value (2nd Volume))

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16 pages, 5663 KiB

Open AccessArticle

Insight into the Structure and Properties of Novel Imidazole-Based Salts of Salicylic Acid

by Inês C. B. Martins, Dominik Al-Sabbagh, Klas Meyer, Michael Maiwald, Gudrun Scholz and Franziska Emmerling

Molecules 2019, 24(22), 4144; https://doi.org/10.3390/molecules24224144 - 15 Nov 2019

Cited by 13 | Viewed by 5574

Abstract

The preparation of new active pharmaceutical ingredient (API) multicomponent crystal forms, especially co-crystals and salts, is being considered as a reliable strategy to improve API solubility and bioavailability. In this study, three novel imidazole-based salts of the poorly water-soluble salicylic acid (SA) are reported exhibiting a remarkable improvement in solubility and dissolution rate properties. All structures were solved by powder X-ray diffraction. Multiple complementary techniques were used to solve co-crystal/salt ambiguities: density functional theory calculations, Raman and ¹H/¹³C solid-state NMR spectroscopies. In all molecular salts, the crystal packing interactions are based on a common charged assisted ⁺N-H_(SA)

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O⁻_(co-former) hydrogen bond interaction. The presence of an extra methyl group in different positions of the co-former, induced different supramolecular arrangements, yielding salts with different physicochemical properties. All salts present much higher solubility and dissolution rate than pure SA. The most promising results were obtained for the salts with imidazole and 1-methylimidazole co-formers. Full article

(This article belongs to the Special Issue Recent Development of Mechanochemical Synthesis)

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