Piperine-hydroxybenzoate as phytochemistry antiosteoarthritis combination: Structural, solubility, and in vivo antiinflammatory study

This study discusses the composition and structure determination of a new multicomponent system from antiinflammatory natural ingredients, consisting of piperine (Pip) and 4-hydroxybenzoic acid (HBA), named Pip-HBA. In addition, this research studied its solubility and anti-inflammatory activity. After screening the stoichiometric proportions, this multicomponent system formation reaction was carried out using the solvent-dropped grinding and evaporation methods. Characterizations using solid analysis including differential scanning calorimetry (DSC), powder X-ray diffractometry (PXRD), and Fourier transform infrared spectroscopy (FTIR), confirmed the formation of Pip-HBA. These multicomponent systems showed different thermograms and diffractograms. Furthermore, the FTIR spectrum of Pip-HBA multicomponent system differs from the physical mixture and its constituent components. Single crystal diffractometry (SCXRD) determined Pip-HBA to be a new multicomponent system structure in three dimensions. Pip-HBA showed increased solubility and anti-inflammatory activity compared to single piperine. Therefore, Pip-HBA multicomponent system has quite potential for further preparation development.

Oleogels for the ocular delivery of epalrestat: formulation, in vitro, in ovo, ex vivo and in vivo evaluation

The ocular administration of lipophilic and labile drugs such as epalrestat, an aldose reductase inhibitor with potential for diabetic retinopathy treatment, demands the development of topical delivery systems capable of providing sufficient ocular bioavailability. The aim of this work was to develop non-aqueous oleogels based on soybean oil and gelators from natural and sustainable sources (ethyl cellulose, beeswax and cocoa butter) and to assess their reproducibility, safety and efficiency in epalrestat release and permeation both ex vivo and in vivo. Binary combinations of gelators at 10% w/w resulted in solid oleogels (oleorods), while single gelator oleogels at 5% w/w remained liquid at room temperature, with most of the oleogels displaying shear thinning behavior. The oleorods released up to 4 µg epalrestat per mg of oleorod in a sustained or burst pattern depending on the gelator (approx. 10% dose in 24 h). The HET-CAM assay indicated that oleogel formulations did not induce ocular irritation and were safe for topical ocular administration. Corneal and scleral ex vivo assays evidenced the permeation of epalrestat from the oleorods up to 4 and 2.5 µg/cm2 after six hours, respectively. Finally, the capacity of the developed oleogels to sustain release and provide significant amounts of epalrestat to the ocular tissues was demonstrated in vivo against aqueous-based niosomes and micelles formulations loaded with the same drug concentration. Overall, the gathered information provides valuable insights into the development of oleogels for ocular drug delivery, emphasizing their safety and controlled release capabilities, which have implications for the treatment of diabetic neuropathy and other ocular conditions.

The bioavailability enhancement and insight into the action mechanism of poorly soluble natural compounds from co-crystals preparation: Oridonin as an example

BACKGROUND

Natural bioactive molecules are important sources for the development of new drugs. However, most of them were limited in clinical applications due to their low aqueous solubility and bioavailability. Oridonin (ORI) is a powerful anticancer compound with above characteristics.

OBJECTIVE

This study aimed to find an effective method to improve the bioavailability of poorly soluble natural compounds, and explore the action mechanisms of them to promote their application.

RESULTS

In this study, ORI-nicotinamide (NCT) cocrystal was successfully prepared for the first time to overcome the defects of ORI. The solubility and oral bioavailability of cocrystal (COC) increased 1.34 and 1.18 times compared with ORI. Moreover, MTT assay was applied to compare the cytotoxicity of positive control drug sorafenib with ORI and COC. The IC50 values of sorafenib, ORI and COC on HepG2 cells were 7.61, 8.79 and 7.36 nmol·mL-1, which indicated that the cytotoxicity of ORI could be enhanced by cocrystal preparation. The cellular metabolomics was innovatively introduced to gain insight into the difference of cytotoxicity mechanism between ORI and COC. The results showed that there were 78 metabolites with significant differences in content between the two groups, while these differential metabolites were related to 11 metabolic pathways. Among these, glycerophospholipid metabolism and cysteine and methionine metabolism were the significant differential pathways, and the downregulation of PC(14:0/16:1(9z)) and upregulation of homocysteine were the likely main reasons for higher cytotoxicity of COC.

CONCLUSIONS

This study has presented novel approaches for enhancing the bioavailability and drug efficacy of natural compounds, while also offering fresh insights into the underlying action mechanisms of pharmaceutical cocrystals.

Towards the Development of Novel Diclofenac Multicomponent Pharmaceutical Solids

Multicomponent pharmaceutical materials offer new opportunities to address drug physicochemical issues and to obtain improved drug formulation, especially on oral administration drugs. This work reports three new multicomponent pharmaceutical crystals of the non-steroidal anti-inflammatory drug diclofenac and the nucleobases adenine, cytosine, and isocytosine. They have been synthesized by mechanochemical methods and been characterized in-depth in solid-state by powder and single crystal X-ray diffraction, as well as other techniques such as thermal analyses and infrared spectroscopy. Stability and solubility tests were also performed on these materials. This work aimed to evaluate the physicochemical properties of these solid forms, which revealed thermal stability improvement. Dissociation of the new phases was observed in water, though. This fact is consistent with the reported observed layered structures and BFDH morphology calculations.

Dual-Loaded Liposomes Tagged with Hyaluronic Acid Have Synergistic Effects in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most lethal subtypes of breast cancer. Although chemotherapy is considered the most effective strategy for TNBC, most chemotherapeutics in current use are cytotoxic, meaning they target antiproliferative activity but do not inhibit tumor cell metastasis. Here, a TNBC-specific targeted liposomal formulation of epalrestat (EPS) and doxorubicin (DOX) with synergistic effects on both tumor cell proliferation and metastasis is described. These liposomes are biocompatible and effectively target tumor cells owing to hyaluronic acid (HA) modification on their surface. This active targeting, mediated by CD44-HA interaction, allows DOX and EPS to be delivered simultaneously to tumor cells in vivo, where they suppress not only TNBC tumor growth and the epithelial-mesenchymal transition, but also cancer stem cells, which collectively suppress tumor growth and metastasis of TNBC and may also act to prevent relapse of TNBC.

Enhanced Oral Bioavailability of Epalrestat SBE7-β-CD Complex Loaded Chitosan Nanoparticles: Preparation, Characterization and in-vivo Pharmacokinetic Evaluation

Background

Epalrestat (EPL) is a carboxylic acid derivative with poor aqueous solubility and its pharmacokinetic features are not fully defined.

Purpose

Current research aimed to fabricate inclusion complexation of EPL with SBE₇ β-CD (IC) and EPL/SBE₇ β-CD CS NPs (NP).

Methods

EPL was complexed with SBE₇ β-CD using the co-precipitation method, and the prepared complex was fabricated into nanoparticles using the ionic gelation method. The prepared formulations were characterized for particle size analysis, surface morphology, and in vitro dissolution study. The % inhibition of EPL against α-glucosidase enzyme was also conducted to check the drug’s antidiabetic activity. Finally, an in vivo pharmacokinetic investigation was carried out to determine the concentration of EPL in rabbit plasma of the prepared formulation. In vivo pharmacokinetic studies were conducted by giving a single dose of pure EPL, IC, and NP.

Results

The size of NP was found to be 241.5 nm with PDI 0.363 and zeta potential of +31.8 mV. The surface of the prepared NP was non-porous, smooth and spherical when compared with pure EPL, SBE₇ β-CD and IC. The cumulative drug release (%) from IC and NP was 73% and 88%, respectively, as compared to pure drug (25%). The % inhibition results for in vitro α-glucosidase was reported to be 74.1% and the predicted binding energy for in silico molecular docking was calculated to be −6.6 kcal/mol. The calculated C_max values for EPL, IC and NP were 4.75±3.64, 66.91±7.58 and 84.27±6.91 μg/mL, respectively. The elimination half-life of EPL was 4 h and reduced to 2 h for IC and NP. The AUC_0-α for EPL, IC and NP were 191.5±164.63, 1054.23±161.77 and 1072.5±159.54 μg/mL*h, respectively.

Conclusion

Taking these parameters into consideration it can be concluded that IC and NP have prospective applications for greatly improved delivery and regulatedt release of poorly water soluble drugs, potentially leading to increase therapeutic efficacy and fewer side effects.

Structure analysis of inclusion crystals of diimide-based macrocycles with halocarbons

Inclusion crystals containing several halocarbons were formed by three types of diimide-based macrocycles. Iodomethane was encapsulated within the cavity of the macrocycle through halogen-related interactions.

Energy framework and solubility: a new predictive model in the evaluation of the structure–property relationship of pharmaceutical solid forms

Crystal structures with lower interaction energy tend to present higher aqueous solubility.

Crystal Structures of Antiarrhythmic Drug Disopyramide and Its Salt with Phthalic Acid

Disopyramide (DPA) is as a class IA antiarrhythmic drug and its crystallization from cyclohexane at ambient condition yields lower melting form crystals which belong to the monoclinic centrosymmetric space group P21/n, having two molecules in an asymmetric unit. Crystal structure analysis of pure DPA revealed closely associated DPA molecules aggregates via amide–amide dimer synthon through the N–H∙∙∙O hydrogen bond whereas the second amide hydrogen N–H engaged in an intramolecular N–H∙∙∙N hydrogen bond with N-nitrogen of 2-pyridine moieties. Crystallization of DPA and phthalic acid (PA) in 1: 1 stoichiometric molar ratio from acetone at ambient condition yielded block shape crystals of 1:1 DPA_PA salt. Its X-ray single crystal structure revealed the formation of salt by transfer of acidic proton from one of the carboxylic acidic groups of PA to the tertiary amino group of chain moiety (N3-nitrogen atom) of DPA molecules. DPA_PA salt crystals belong to the monoclinic centrosymmetric space group P21/n, comprising one protonated DPA and one PA¯ anion (hydrogen phthalate counterion) in an asymmetric unit and linked by N–H∙∙∙O and C–H∙∙∙O hydrogen bonds. Pure DPA and DPA_PA salt were further characterized by differential calorimetric analysis, thermal gravimetric analysis, powder x-ray diffraction and infrared spectroscopy.

Structural variety of heterosynthons in linezolid cocrystals with modified thermal properties

In a search for new crystalline forms of linezolid with modified thermal properties five cocrystals of this wide range antibiotic with aromatic acids were obtained via mechanochemical grinding and analyzed with single crystal X-ray diffraction, solid-state NMR spectroscopy, powder X-ray diffraction and DSC measurements. The coformers used in this study were benzoic acid, p-hydroxybenzoic acid, protocatechuic acid, γ-resorcylic acid and gallic acid. In each of the cocrystals distinct structural features have been found, including a variable amount of water and different heterosynthons, indicating that there is more than one type of intermolecular interaction preferred by the linezolid molecule. Basing on the frequency of the observed supramolecular synthons, the proposed hierarchy of the hydrogen-bond acceptor sites of linezolid (LIN) is C=O_amide > C=O_oxazolidone > C-O-C_morpholine > C-N-C_morpholine > C-O-C_oxazolidone. In addition, aromatic-aromatic interactions were found to be important in the stabilization of the analyzed structures. The obtained cocrystals show modified thermal properties, with four of them having melting points lower than the temperature of the phase transition from linezolid form II to linezolid form III. Such a change in this physicochemical property allows for the future application of melting-based techniques of introducing linezolid into drug delivery systems. In addition a change in water solubility of linezolid upon cocrystalization was evaluated, but only in the case of the cocrystal with protocatechuic acid was there a significant (43%) improvement in solubility in comparison with linezolid.

Composing Novel Diclofenac Potassium and l-Proline Salt Cocrystal as a Strategy to Increase Solubility and Dissolution

This research dealt with the multicomponent crystal developed from diclofenac potassium and l-proline to improve the pharmaceutical performance of this anti-inflammatory drug. Slow evaporation of the component mixture at a 1:1 M ratio, supported by ultrasonication, yielded a new salt cocrystal, which was characterized using thermal analysis, Karl Fischer titration, infrared spectrophotometry, powder diffractometry, and single crystal diffractometry. This salt cocrystal was confirmed as a tetrahydrate that comprised diclofenac potassium, l-proline, and water (1:1:4), named DKPH. The new salt cocrystal enhanced the solubility of diclofenac potassium by up to 3.56 folds and accelerated the intrinsic dissolution rate of 3.36 folds. It was supported by the solid and solution phase intermolecular interaction study. A different phase, which indicated a monohydrate form of the salt cocrystal, was found from the low humidity chamber during the isotherm sorption study. However, the tetrahydrate, DKPH, was proven as a stable form under ambient conditions.

Salt Cocrystal of Diclofenac Sodium-L-Proline: Structural, Pseudopolymorphism, and Pharmaceutics Performance Study

Previously, we have reported on a zwitterionic cocrystal of diclofenac acid and L-proline. However, the solubility of this multicomponent crystal was still lower than that of diclofenac sodium salt. Therefore, this study aimed to observe whether a multicomponent crystal could be produced from diclofenac sodium hydrate with the same coformer, L-proline, which was expected to improve the pharmaceutics performance. Methods involved screening, solid phase characterization, structure determination, stability, and in vitro pharmaceutical performance tests. First, a phase diagram screen was carried out to identify the molar ratio of the multicomponent crystal formation. Next, the single crystals were prepared by slow evaporation under two conditions, which yielded two forms: one was a rod-shape and the second was a flat-square form. The characterization by infrared spectroscopy, thermal analysis, and diffractometry confirmed the formation of the new phases. Finally, structural determination using single crystal X-ray diffraction analysis solved the new salt cocrystals as a stable diclofenac-sodium-proline-water (1:1:1:4) named NDPT (natrium diclofenac proline tetrahydrate), and unstable diclofenac-sodium-proline-water (1:1:1:1), named NDPM (natrium diclofenac proline monohydrate). The solubility and dissolution rate of these multicomponent crystals were superior to those of diclofenac sodium alone. The experimental results that this salt cocrystal is suitable for further development.

Improved Solubility and Dissolution Rates in Novel Multicomponent Crystals of Piperine with Succinic Acid

The objectives of this study were to prepare and characterize a novel piperine–succinic acid multicomponent crystal phase and to evaluate the improvement in the solubility and dissolution rate of piperine when prepared in the multicomponent crystal formation. The solid-state characterization of the novel multicomponent crystal was performed by powder X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform-infrared (FT-IR) spectroscopy. Solubility and dissolution rate profiles were evaluated in distilled water. The physical stability was evaluated under high relative humidity (75% and 100% RH). The determination of the single crystal X-ray diffraction structure revealed that this novel multicomponent crystal was a cocrystalline phase of piperine–succinic acid (2:1 molar ratio). The differential scanning calorimetry thermogram of the cocrystal showed a single and sharp endothermic peak at 110.49 °C. The cocrystal resulted in greater solubility and a faster dissolution rate of piperine than intact piperine. This improvement was a result of the formation of a channel structure in the cocrystal. In addition, the cocrystal was stable under a humid condition.

Characterizations and Assays of α-Glucosidase Inhibition Activity on Gallic Acid Cocrystals: Can the Cocrystals be Defined as a New Chemical Entity During Binding with the α-Glucosidase?

Cocrystallization with co-former (CCF) has proved to be a powerful approach to improve the solubility and even bioavailability of poorly water-soluble active pharmaceutical ingredients (APIs). However, it is still uncertain whether a cocrystal would exert the pharmacological activity in the form of a new chemical entity, an API-CCF supramolecule. In the present study, gallic acid (GA)-glutaric acid and GA-succinimide cocrystals were screened. The solubility, dissolution rate and oral bioavailability of the two cocrystals were evaluated. As expected, AUCs of GA-glutaric acid and GA-succinimide cocrystals were 1.86-fold and 2.60-fold higher than that of single GA, respectively. Moreover, experimental evaluations on α-glucosidase inhibition activity in vitro and theoretical simulations were used to detect whether the two cocrystals would be recognized as a new chemical entity during binding with α-glucosidase, a target protein in hypoglycemic mechanisms. The enzyme activity evaluation results showed that both GA and glutaric acid displayed α-glucosidase inhibition activity, and GA-glutaric acid cocrystals showed strengthened α-glucosidase inhibition activity at a moderate concentration, which is attributed to synergism of the two components. Molecular docking displayed that the GA-glutaric acid complex deeply entered the active cavity of the α-glucosidase in the form of a supramolecule, which made the guest-enzyme binding configuration more stable. For the GA and succinimide system, succinimide showed no enzyme inhibition activity, however, the GA-succinimide complex presented slightly higher α-glucosidase inhibition activity than that of GA. Molecular docking simulation indicated that the guest molecules entering the active cavity of the α-glucosidase were free GA and succinimide, not the GA-succinimide supramolecule.

Crystal Structural Analysis of DL-Mandelate Salt of Carvedilol and Its Correlation with Physicochemical Properties

A 1:1 salt of carvedilol (CVD), an anti-hypertensive drug, with DL-mandelic acid (DL-MA) was crystallized from ethanol and the structure was characterized by X-ray single-crystal diffraction, revealing salt formation by transfer of an acidic proton from the COOH group of MA to the aliphatic (acyclic) secondary amino NH group of CVD. The crystal structure is triclinic, with a P-1 space group and unit cell parameters a = 9.8416(5) Å, b = 11.4689(5) Å, c = 14.0746(7) Å, α = 108.595(8), β = 95.182(7), γ = 107.323(8), V = 1406.95(15) Å3, and Z = 2. The asymmetric unit contained one protonated CVD and one MA anion, linked via an N+–H∙∙∙O¯ strong hydrogen bond and a ratio of 1:1. As previously reported, the thermal, spectroscopic, and powder X-ray diffraction properties of the salt of CVD with DL-MA (CVD_DL-MA) differed from CVD alone. The intrinsic dissolution rate of CVD_DL-MA was about 10.7 times faster than CVD alone in a pH 6.8 buffer.

A peculiar dehydration and solid–solid phase transition of the active pharmaceutical ingredient AZD9898 based on in situ single crystal-to-single crystal transformations

Isostructural dehydration from form A hydrate to form B, and solid–solid phase transition from form B to C of AZD9898 were revealed by in situ single crystal-to-single crystal transformations.

Mechanochemical synthesis of drug–drug and drug–nutraceutical multicomponent solids of olanzapine

Drug–drug and drug–nutraceutical multicomponent solids of an antipsychotic drug olanzapine (OLN) are prepared using mechanochemistry.

Co-Inclusion of cyclic ethers and chloroform by a macrocycle with benzophenone-3,3′,4,4′-tetracarboxylic diimide units

Crystallization of a diimide-based macrocycle having adamantane parts and several cyclic ethers in chloroform provided inclusion crystals, where both guests were cooperatively accommodated within inner spaces between the macrocycles.

A New Ferulic Acid-Nicotinamide Cocrystal With Improved Solubility and Dissolution Performance

Among the various strategies for increasing aqueous solubility of pharmaceutical substances, cocrystals have been emerging as a promising alternative. The ferulic acid (FEA) is a molecule with limited aqueous solubility, but with an interesting pharmacological activity, highlighting its antitumor potential. This study presents the characterization and physicochemical properties of a new cocrystal based on FEA and nicotinamide (NIC). The FEA-NIC cocrystal was obtained by solvent evaporation technique and physicochemically characterized by differential scanning calorimetry, powder X-ray diffraction, Fourier transform infrared spectroscopy, solid-state nuclear magnetic resonance and scanning electron microscopy. The content determination and dissolution profile in different media were analyzed by high-performance liquid chromatography. The results obtained with the characterization techniques indicated the obtainment of an anhydrous cocrystal of FEA and NIC at a 1:1 molar ratio. The method was reproducible and obtained a high yield, of approximately 99%. In addition, a 70% increase in the FEA solubility in the cocrystal and a better dissolution performance than the physical mixture in pH 6.8 were achieved.

Understanding the formation of apremilast cocrystals

Apremilast (APR), an anti-psoriatic agent, easily forms isostructural cocrystals and solvates with aromatic entities, often disobeying at the same time Kitaigorodsky's rule as to the saturation of possible hydrogen-bonding sites. In this paper the reasons for this peculiar behavior are investigated, employing a joint experimental and theoretical approach. This includes the design of cocrystals with coformers having a high propensity towards the formation of both aromatic-aromatic and hydrogen-bonding interactions, determination of their structure, using solid-state NMR spectroscopy and X-ray crystallography, as well as calculations of stabilization energies of formation of the obtained cocrystals, followed by crystal structure prediction calculations and solubility measurements. The findings indicate that the stabilization energies of cocrystal formation are positive in all cases, which results from strain in the APR conformation in these crystal forms. On the other hand, solubility measurements show that the Gibbs free energy of formation of the apremilast:picolinamide cocrystal is negative, suggesting that the formation of the studied cocrystals is entropy driven. This entropic stabilization is associated with the disorder observed in almost all known cocrystals and solvates of APR.

Multicomponent Crystal of Mefenamic Acid and N-Methyl-d-Glucamine: Crystal Structures and Dissolution Study

A novel multicomponent crystal (MC) of mefenamic acid (MA) and N-methyl-d-glucamine (MG) had been prepared to improve the physicochemical properties of poorly soluble drugs, and was characterized for its physicochemical properties by powder X-ray diffraction analysis, differential scanning calorimetry thermal analysis, FT-IR spectroscopy, in vitro dissolution rate, and physical stability. In addition, the crystal structure was determined by single-crystal X-ray diffraction analysis. The differential scanning calorimetry thermogram of the MA-MG binary system exhibits a single and sharp endothermic peak at 151.20°C, which was attributed to the melting point of a MC of MA-MG. FT-IR spectroscopy analysis showed the occurrence of solid-state interaction by involving proton transfer between MA and MG. The crystal structure analysis confirmed that MA-MG formed 1:1 ratio salt type MC. The formation of a MC of MA with MG significantly improved the dissolution rate of MA in compared to intact MA, and also the crystal demonstrated a good stability under a high relative humidity. These good properties would be attributed to the layer structure of MA and MG in the crystal.

Confocal Raman micro-spectral evidence and physicochemical evaluation of triamterene salts

Discrimination of active pharmaceutical ingredients (APIs) existing as neutral molecules or salts is essential and complicated. However, the discrimination of pharmaceutical salts by confocal Raman micro-spectroscopy remains relatively poorly understood. In this paper, four new salts of triamterene (Tri) cocrystallized with nicotinic acid (NA), benzoic acid (BA), p-toluenesulfonic acid (TA), or isonicotinic acid (INA) were prepared and characterized comprehensively by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), polarized light microscopy (PLM), and dynamic vapor sorption (DVS). Ionized pteridine is identified by marker peaks in the confocal Raman micro-spectra that are characteristic of C[double bond, length as m-dash]N. The single crystal structures of Tri-NA·H2O and Tri-TA further demonstrate that a proton transfers from the carboxylic group of NA or TA to the pyrimidine N1 atom of Tri and their salts formation take place. The intrinsic dissolution rate (IDR) and apparent equilibrium solubility of these four salts are improved compared to the pure Tri component, especially for Tri-BA. This study provides a valuable insight into pharmaceutical salt discrimination by vibrational spectroscopy and presents that the combination of Tri with an acid can be a possible and promising alternative formulation of Tri.

The effects of pH, surfactant, ion concentration, coformer, and molecular arrangement on the solubility behavior of myricetin cocrystals

Pharmaceutical cocrystals are a promising technology that can be used to improve the solubility of poor aqueous compounds. The objective of this study was to systematically investigate the solubility of myricetin (MYR) cocrystals, including their kinetic solubility, thermodynamic solubility, and intrinsic dissolution rate (IDR). The effects of pH, surfactant, ion concentration, and coformers on the cocrystal solubility were evaluated. Furthermore, single crystal structures of MYR, myricetin–isonicotinamide (MYR–INM) and myricetin–caffeine (MYR–CAF) cocrystals were analyzed to discuss the possible reasons for the enhancement of cocrystal solubility from the perspective of the spatial structure. The results indicated that the kinetic solubility of MYR cocrystals was modulated by pH and cocrystal coformer (CCF) ionization in buffer solution, while it primarily depended on the CCF solubility in pure water. In addition, the solubility of MYR cocrystals was increased in a concentration dependent fashion by the surfactant or ion concentration. The thermodynamic solubility of MYR–INM (1:3) cocrystals decreased with the increases of the pH value of the dissolution media. The IDR of MYR cocrystals was faster than that of MYR in the same medium and extremely fast in pH 4.5 buffer. The improved solubility of MYR cocrystals was probably related to the alternate arrangements of MYR and INM/CAF molecules and increased intermolecular distance. The present study provides some references to investigate the solubility behavior of pharmaceutical cocrystals.

Cocrystal of Ibuprofen⁻Nicotinamide: Solid-State Characterization and In Vivo Analgesic Activity Evaluation

Ibuprofen is classified as a BCS class II drug which has low solubility and high permeability. We conducted the formation of the cocrystalline phase of ibuprofen with coformer nicotinamide to increase its solubility. The purpose of this study was to characterize the solid state of cocrystalline phase of ibuprofen-nicotinamide, determine the solubility, and evaluate its in vivo analgesic activity. The cocrystal of ibuprofen-nicotinamide was prepared by a slow evaporation method. The solid-state characterization was conducted by powder X-ray diffraction (PXRD) analysis, differential thermal analysis (DTA), and scanning electron microscopy (SEM). To investigate the in vivo analgesic activity, 28 male Swiss-Webster mice were injected with acetic acid 0.5% following oral administration of intact ibuprofen, physical mixture, and its cocrystalline phase with nicotinamide (equivalent to 26 mg/kg ibuprofen). The number of writhes was counted, and pain inhibition was calculated. All data were analyzed with one-way ANOVA followed by Duncan's Multiple Range Test (95% confidence interval). The results revealed that a new cocrystalline phase was successfully formed. The solubility testing showed that the cocrystal formation enhanced the solubility significantly as compared with the physical mixture and intact ibuprofen. A significant increase in the analgesic activity of cocrystal ibuprofen-nicotinamide was also confirmed.

Solubility Improvement of Benexate through Salt Formation Using Artificial Sweetener

Benexate, a drug used clinically as a defensive type anti-ulcer agent, has poor solubility and a bitter taste. To improve its solubility, a crystal engineering approach was proposed with the formation of novel salts using an artificial sweetener as a salt co-former. This was also expected to address the bitter taste of the drug. In this work, we report on the preparation and evaluation of the physicochemical properties of the novel salts benexate saccharinate monohydrate and benexate cyclamate whose crystal structures were determined by single-crystal X-ray structure analysis. These novel salts showed higher solubility and faster dissolution profiles that were associated with the occurrence of local layered-like structures. They also showed better moisture uptake profiles and were classified as non-hygroscopic materials. Therefore, benexate saccharinate monohydrate and benexate cyclamate expedited the development of sweet pharmaceutical salts of benexate with improved performances.

Anhydrates and hemihydrate of tasimelteon: Synthesis, structure, and pharmacokinetic study

Two new crystal forms of tasimelteon TSM-I and TSM-II were reported here. Crystallization of crude in methanol or mixture solvent results in anhydrate crystal form (TSM-I) and hemihydrate crystal form (TSM-II) respectively. To the best of our knowledge, it is the first report about crystalline form of tasimelteon. The two crystal forms were exhaustively characterized by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, Raman Spectra, Differential Scanning Calorimetry, Thermogravimetric Analysis, Solid State NMR Spectroscopy and Powder X-ray diffraction and Single Crystal X-ray Diffraction. Furthermore, the pharmacokinetic behavior of TSM-I and TSM-II in rats were measured. We found that though TSM-II is considerably more soluble than TSM-I under water (pH = 7.0) and pH 1.2 buffer conditions, the bioavailability of TSM-Ivia oral administration was better compared to that of TSM-II.

Suppressed hydration in metoclopramide hydrochloride by salt cocrystallisation

Salt cocrystallisation method successfully suppressed hydration and lowered the dissolution rate of the pharmaceutical salt crystals.

Epalrestat tetra-hydro-furan monosolvate: crystal structure and phase transition

The title compound, epalrestat {systematic name: (5Z)-5-[(2E)-2-methyl-3-phenyl-prop-2-en-1-yl-idene]-4-oxo-2-sulfanyl-idene-1,3-thia-zolidine-3-acetic acid}, crystallized as a tetra-hydro-furan monosolvate, C15H13NO3S2·C4H8O. Epalrestat, an important drug for diabetic neuropathy, has been reported to exist in polymphic, solvated and co-crystal forms. In the mol-ecule reported here, the phenyl ring is inclined to the rhodamine ring by 22.31 (9)°, and the acetic acid group is almost normal to the rhodamine ring, making a dihedral angle of 88.66 (11)°. In the crystal, pairs of O-H⋯O hydrogen bonds are observed between the carb-oxy-lic acid groups of epalerstat mol-ecules, forming inversion dimers with an R22(8) loop. The dimers are linked by pairs of C-H⋯O hydrogen bonds, forming chains along [101]. The solvate mol-ecules are linked to the chain by a C-H⋯O(tetra-hydro-furan) hydrogen bond. A combination of thermal analysis and powder X-ray diffraction revealed that title compound desolvated into epalerstat Form II. One C atom of the tetra-hydro-furan solvate mol-ecule is positionally disordered and has a refined occupancy ratio of 0.527 (18):0.473 (18).

Investigation of the solid forms of deferasirox: solvate, co-crystal, and amorphous form

Five solid forms of deferasirox were prepared, characterized and preliminarily investigated.