Solid-state characterization and solubility of a genistein–caffeine cocrystal

Genistein Co-Amorphous Systems with Amino Acids: An Investigation into Enhanced Solubility and Biological Activity

Genistein, an isoflavone known for its antioxidant and antidiabetic effects, suffers from the drawback of low solubility. To overcome this limitation, co-amorphous systems were synthesized by incorporating amino acids that were chosen through computational methods. The confirmation of the amorphous state of lysine and arginine-containing systems was ascertained by X-ray powder diffraction. Subsequently, the characterization of these systems was extended by employing thermo-gravimetry, differential scanning calorimetry, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The investigation also included an assessment of the physical stability of the samples during storage. The apparent solubility of the systems was studied in an aqueous medium. To evaluate the in vitro permeability through the gastrointestinal tract, the parallel artificial membrane permeability assay was employed. The biological properties of the systems were assessed with regard to their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl and cupric ion-reducing antioxidant capacity assays, as well as their ability to inhibit α-glucosidase. The systems' glass transition temperatures were determined, and their homogeneity confirmed via differential scanning calorimetry analysis, while Fourier-transform infrared spectroscopy analysis provided data on molecular interactions. Stability was maintained for the entire 6-month storage duration. The co-amorphous system containing lysine displayed the most pronounced apparent solubility improvement, as well as a significant enhancement in antioxidant activity. Notably, both systems demonstrated superior α-glucosidase inhibition relative to acarbose, a standard drug for managing type 2 diabetes. The results indicate that co-amorphous systems with lysine and arginine have the potential to significantly enhance the solubility and biological activity of genistein.

Optimized solubility and bioavailability of genistein based on cocrystal engineering

With various potential health-promoting bioactivities, genistein has great prospects in treatment of a series of complex diseases and metabolic syndromes such as cancer, diabetes, cardiovascular diseases, menopausal symptoms and so on. However, poor solubility and unsatisfactory bioavailability seriously limits its clinical application and market development. To optimize the solubility and bioavailability of genistein, the cocrystal of genistein and piperazine was prepared by grinding assisted with solvent based on the concept of cocrystal engineering. Using a series of analytical techniques including single-crystal X-ray diffraction, powder X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis, the cocrystal was characterized and confirmed. Then, structure analysis on the basis of theoretical calculation and a series of evaluation on the stability, dissolution and bioavailability were carried out. The results indicated that the cocrystal of genistein and piperazine improved the solubility and bioavailability of genistein. Compared with the previous studies on the cocrystal of genistein, this is a systematic and comprehensive investigation from the aspects of preparation, characterization, structural analysis, stability, solubility and bioavailability evaluation. As a simple, efficient and green approach, cocrystal engineering can pave a new path to optimize the pharmaceutical properties of natural products for successful drug formulation and delivery.

Using Prenucleation Aggregation of Caffeine-Benzoic Acid as a Rapid Indication of Co-crystallization from Solutions

Co-crystal design is a convenient way to remedy the poor biopharmaceutical properties of drugs. Most studies focus on experimental co-crystal screening or computational prediction, but hardly any work has been done toward fast, efficient, and reliable prediction of solution crystallization for co-crystal formation. Here, we study the caffeine-benzoic acid co-crystal system, due to its reported difficulty to crystallize from the solution phase. With this work, we investigate whether there is a link between prenucleation aggregation in solution and co-crystal formation and how to harness this for crystallization prediction. ¹H and ¹³C NMR spectroscopy is used to study the prenucleation interaction between caffeine and benzoic acid in methanol, acetone, and acetonitrile as examples of common solvents. In this system, crystallization from methanol leads to no co-crystallization, from acetone to concomitant crystallization of co-crystal and caffeine, and from acetonitrile to pure co-crystal formation from solution. Strong heteromeric dimers were found to exist in all three solvents. Ternary phase diagrams were defined and a solution-accessible co-crystal region was found for all solvents. For this system, the prenucleation clusters found in solution could be linked to the crystallization of the co-crystal. Crystallization from DMSO did not yield the co-crystal and there were no detectable prenucleation aggregates. NMR spectroscopy to probe dimers in solution can thus be used as a fast, reliable, and promising tool to predict co-crystallization from specific solvents and to screen for suitable solvents for manufacturing and scale-up.

Recent Advances in Pharmaceutical Cocrystals: A Focused Review of Flavonoid Cocrystals

Cocrystallization is currently an attractive technique for tailoring the physicochemical properties of active pharmaceutical ingredients (APIs). Flavonoids are a large class of natural products with a wide range of beneficial properties, including anticancer, anti-inflammatory, antiviral and antioxidant properties, which makes them extensively studied. In order to improve the properties of flavonoids, such as solubility and bioavailability, the formation of cocrystals may be a feasible strategy. This review discusses in detail the possible hydrogen bond sites in the structure of APIs and the hydrogen bonding networks in the cocrystal structures, which will be beneficial for the targeted synthesis of flavonoid cocrystals. In addition, some successful studies that favorably alter the physicochemical properties of APIs through cocrystallization with coformers are also highlighted here. In addition to improving the solubility and bioavailability of flavonoids in most cases, flavonoid cocrystals may also alter their other properties, such as anti-inflammatory activity and photoluminescence properties.

Improving the Physicochemical and Biopharmaceutical Properties of Active Pharmaceutical Ingredients Derived from Traditional Chinese Medicine through Cocrystal Engineering

Active pharmaceutical ingredients (APIs) extracted and isolated from traditional Chinese medicines (TCMs) are of interest for drug development due to their wide range of biological activities. However, the overwhelming majority of APIs in TCMs (T-APIs), including flavonoids, terpenoids, alkaloids and phenolic acids, are limited by their poor physicochemical and biopharmaceutical properties, such as solubility, dissolution performance, stability and tabletability for drug development. Cocrystallization of these T-APIs with coformers offers unique advantages to modulate physicochemical properties of these drugs without compromising the therapeutic benefits by non-covalent interactions. This review provides a comprehensive overview of current challenges, applications, and future directions of T-API cocrystals, including cocrystal designs, preparation methods, modifications and corresponding mechanisms of physicochemical and biopharmaceutical properties. Moreover, a variety of studies are presented to elucidate the relationship between the crystal structures of cocrystals and their resulting properties, along with the underlying mechanism for such changes. It is believed that a comprehensive understanding of cocrystal engineering could contribute to the development of more bioactive natural compounds into new drugs.

Delivery Mechanism of the Pharmaceutical Complex of Genistein-Adenine Based on Spectroscopic and Molecular Modelling at Atomic Scale

Genistein (GS) exhibits various biological activities, but its clinical application is limited because of the low bioavailability. In this study, a GS-adenine pharmaceutical complex was prepared through solvent evaporation to improve the bioavailability of GS, and a molecular model of a two-component supramolecular pharmacological transport mechanism was established. The structure of GS-adenine was characterized, in addition, interaction patterns between GS and adenine were investigated using density functional theory. The results showed that the solubility of GS-adenine was five times higher than that of GS, and the cumulative release rate of GS-adenine was 86 %. The results of fluorescence spectroscopy and molecular dynamic simulations showed that GS-adenine bound to the Sudlow's site I of HSA mainly through hydrophobic interactions. This study provides a useful reference for synthesizing pharmaceutical complexes to improve solubility and for exploring the mechanism of multiple pharmaceutical components in vivo.

The role of 3-OH in the self-assembly of pharmaceutical cocrystals of dihydroflavonol with 4,4′-bipyridine

The 3-OH group of nonplanar dihydroflavonols participates in the formation of hydrogen bonds with BPY, thereby forming cocrystals with different structures.

Molecular interaction between MeOH and genistein during soy extraction

Genistein has received great attention due to its possible anti-oxidant properties. The interaction between genistein and the extraction solvent helps in understanding the extraction efficiency. Hydrogen bonding plays a crucial role in liquid systems. Density functional theory quantum chemical computations in both gas phase and solution were performed to investigate the molecular interaction between genistein and methanol. All the resulting complexes (MeOH : genistein = 1 : 1, 2 : 1, 3 : 1, 6 : 1) were studied using the B3LYP-D3 computational level and the cc-pVTZ basis set. Binding energies demonstrate that more MeOH molecules surrounding genistein could stabilize the system more. Geometry optimizations show that there are strong O–H⋯O interactions between MeOH and genistein. The electron density and the corresponding Laplacian of charge density at bond critical points were also calculated using AIM theory, and the results are in line with the structural and energetic analysis of the studied system. Moreover, energy decomposition analysis shows that the exchange energy term has the largest contribution to the attraction interaction energy as compared with other energy terms. Meanwhile, this study shows that the MeOH–genistein system is more stable under basic conditions. This study could help increase the efficiency of extraction.

The interaction between genistein and extraction solvent helps in understanding the extraction efficiency.

DSC, FTIR and Raman Spectroscopy Coupled with Multivariate Analysis in a Study of Co-Crystals of Pharmaceutical Interest

Co-crystals have garnered increasing interest in recent years as a beneficial approach to improving the solubility of poorly water soluble active pharmaceutical ingredients (APIs). However, their preparation is a challenge that requires a simple approach towards co-crystal detection. The objective of this work was, therefore, to verify to what extent a multivariate statistical approach such as principal component analysis (PCA) and cluster analysis (CA) can be used as a supporting tool for detecting co-crystal formation. As model samples, physical mixtures and co-crystals of indomethacin with saccharin and furosemide with p-aminobenzoic acid were prepared at API/co-former molar ratios 1:1, 2:1 and 1:2. Data acquired from DSC curves and FTIR and Raman spectroscopies were used for CA and PCA calculations. The results obtained revealed that the application of physical mixtures as reference samples allows a deeper insight into co-crystallization than is possible with the use of API and co-former or API and co-former with physical mixtures. Thus, multivariate matrix for PCA and CA calculations consisting of physical mixtures and potential co-crystals could be considered as the most profitable and reliable way to reflect changes in samples after co-crystallization. Moreover, complementary interpretation of results obtained using DSC, FTIR and Raman techniques is most beneficial.

Pharmaceutical cocrystals of naringenin with improved dissolution performance

Four pharmaceutical cocrystals of naringenin were obtained, which demonstrate improved dissolution performance.