Drug-Drug Cocrystal Alloy and Nanoformulation of Cytarabine: Optimized Biopharmaceutical Property and Synergistic Antitumor Efficacy.

An integrated strategy by combining cocrystallization with nanotechnology is developed to optimize in vitro/vivo performances of marine antitumor drug cytarabine (ARA) and further obtain innovative insights into the exploitation of cocrystal alloy nanoformulation. Therein, the optimization of properties and synergistic effects of ARA mainly depends on assembling with uracil (U) and antitumor drug 5-fluorouracil (FU) into the same crystal by cocrystallization technology, while the long-term efficacy is primarily maintained by playing the superiority of nanotechnology. Along this line, the first cocrystal alloy of ARA, viz., ARA-FU-U (0.6:0.4), is successfully obtained and then transformed into a nanocrystal. Single-crystal X-ray diffraction analysis demonstrates that this cocrystal alloy consists of two isomorphic cocrystals of ARA, namely, ARA-FU and ARA-U, in 0.6:0.4 ratio. An R22(8) hydrogen-bonding cyclic system formed by a cytosine fragment of ARA with U or FU can protect and stabilize the amine group on ARA, laying the foundation for regulating its properties. The in vitro/in vivo properties of the cocrystal alloy and its nanocrystals are investigated by theoretical and experimental means. It reveals that both the alloy and nanocrystal can improve physicochemical properties and promote drug absorption, thus bringing to optimized pharmacokinetic behaviors. The nanocrystal produces superior effects than the alloy that helps to extend therapeutic time and action. Particularly, relative to the corresponding binary cocrystal, the synergistic antitumor activity of ARA and FU in the cocrystal alloy is heightened obviously. It may be that U contributes to reducing the degradation of FU, specifically increasing its concentration in tumors to enhance the synergistic effects of FU and ARA. These findings provide new thoughts for the application of cocrystal alloys in the marine drug field and break fresh ground for cocrystal alloy formulations to optimize drug properties.

Cocrystallization-Driven Double-Optimized Stratagem toward Directional Self-Assembly for the First Ternary Salt Cocrystal of Cardiotonic Drug Milrinone with Different Phenolic Acids Exhibits Optimal In Vitro/Vivo Biopharmaceutical Peculiarities.

The current research leverages the structural features and property superiorities along with benefits in protecting cardiovascular system of gallic acid (GLC) and gentisic acid (HGA) to optimize in vitro/vivo peculiarities of cardiotonic drug milrinone (MIL) through developing a stratagem of cocrystallization-driven double-optimized ternary salt cocrystal. This strategy assembles MIL ternary salt cocrystal by shaping a cocrystallization moiety relying on noncovalent interplays with GLC to obtain permeability advancement and molding a salt segment via the salification of proton transfer between HGA and MIL molecules to facilitate solubility enhancement. While the ameliorative in vitro properties further modulate the in vivo pharmacokinetic behaviors, thus fulfilling a dual optimization of MIL's biopharmaceutical characteristics on both in vitro and in vivo aspects. Along this line, the first MIL ternary salt cocrystal, viz., [HMIL+-GA-]-MIL-GLC-H2O (denoted as MTSC hereinafter), has been satisfactorily constructed and precisely structurally identified by diversified techniques. The single-crystal X-ray diffraction experiment validates that a molecular salt [HMIL+-GA-] species cocrystallizes with one neutral MIL, two GLC, and five solvent water molecules, among which the organic constituents compose laminated hydrogen bond networks, and then are self-assembled by water molecules to a 3D supramolecular structure. The unique structural feature and stacking pattern of MTSC make both the permeability and solubility be respectively enhanced by 9.69 times and 5.17- to 6.03-fold compared with the parent drug per se. The experimental outcomes are powerfully supported by associated calculations based on density functional theory. Intriguingly, these optimal in vitro physicochemical natures of MTSC have been potently converted into strengths of in vivo pharmacokinetics, showcasing the elevated drug plasma concentration, elongated half-life, alongside advanced bioavailability. Consequently, this presentation not just contributes a brand-new crystalline form with utility values, but ushers in a new dimension of ternary salt cocrystals for improving in vitro/vivo limitations of poor drug bioavailability.

Correction: Supramolecular self-assembly of amantadine hydrochloride with ferulic acid via dual optimization strategy establishes a precedent of synergistic antiviral drug-phenolic acid nutraceutical cocrystal.

Correction for 'Supramolecular self-assembly of amantadine hydrochloride with ferulic acid via dual optimization strategy establishes a precedent of synergistic antiviral drug-phenolic acid nutraceutical cocrystal' by Ling-Yang Wang et al., Analyst, 2021, 146, 3988-3999, https://doi.org/10.1039/D1AN00478F.

Supramolecular self-assembly of amantadine hydrochloride with ferulic acid via dual optimization strategy establishes a precedent of synergistic antiviral drug-phenolic acid nutraceutical cocrystal.

To display the capability of the phenolic acid nutraceutical ferulic acid (FLA) in optimizing the in vitro/in vivo properties of the antiviral drug amantadine hydrochloride (AMH) and achieve synergistically enhanced antiviral effects, thereby gaining some new insights into pharmaceutical cocrystals of antiviral drugs with phenolic acid nutraceuticals, a cocrystallization strategy of dual optimization was created. Based on this strategy, the first drug-phenolic acid nutraceutical cocrystal of AMH with FLA, namely AMH-FLA-H2O, was successfully assembled and completely characterized by employing single-crystal X-ray diffraction and other analytical techniques. The cocrystal was revealed to be composed of AMH, FLA, and water molecules in the ratio of 3 : 1 : 1.5, and charge-assisted hydrogen bonds containing chloride ions crucially maintained the crystal lattice together with water molecules. The in vitro/in vivo properties of the cocrystal were systematically evaluated via both theoretical and experimental methods, and the results indicate that the dissolubility of AMH is down-regulated by two-thirds in the cocrystal, resulting in its potential for sustained pharmacokinetic release and the elimination of the adverse effects of AMH. More importantly, the enhanced antiviral effects of the current cocrystal were proven against four viral strains, and the pharmaceutical synergy between AMH and FLA was realized with a combination index (CI) of less than 1. Thus, the present work provides a novel crystalline product with bright commercial prospect for the classical antiviral drug AMH and also establishes an avenue for the synergetic antiviral application of nutraceutical phenolic acids via the cocrystallization strategy of dual optimization.

Supramolecular self-assembly and perfected in vitro/vivo property of 5-fluorouracil and ferulic acid on the strength of double optimized strategy: the first 5-fluorouracial-phenolic acid nutraceutical cocrystal with synergistic antitumor efficacy.

For highlighting the predominance of phenolic acid nutraceutical ferulic acid (FR) in regulating the in vivo/vitro performances of anticancer drug 5-fluorouracil (Flu) and strengthening their cooperativity in antitumor effect, thus achieving a major breakthrough in the development of drug-nutraceutical cocrystal with synergistic antitumor action, a cocrystallization strategy of dual optimization is created, in which both the in vivo and vitro natures of Flu are improved by exploiting the FR's excellent physicochemical property. Moreover, Flu's anticancer effects were promoted by exerting the assistant antitumor peculiarity of FR. Such dual optimization of FR for Flu in physicochemical properties and anticancer activities is beneficial for realizing synergistic augmentation effect by taking the benefit of the cooperativeness of Flu and FR in the anticancer ability. Based on this idea, a novel cocrystal of Flu and FR, namely, Flu-FR-H2O, is successfully assembled as the first 5-fluorouracil-nutraceutical cocrystal with synergistic antitumor effect and its explicit structure is resolved. The single-crystal X-ray diffraction demonstrates that Flu and FR have a ratio of 1 : 1 with one equivalent of solvent water in the cocrystal, where one-dimensional hydrogen-bonding helices and FR-Flu hydrogen-bonding pairs, together construct a three-dimensional supramolecular network. By combining experimental evaluation with theoretical analysis, in vitro/vivo pharmaceutical properties are scientifically investigated. Results show that the permeability and aqueous solubility of Flu are respectively elevated by 5.08 and 1.64 folds, which has brought about ameliorated pharmacokinetics, thus providing prolonged retention time and increased oral bioavailability. More interestingly, the cocrystal shows synergistic inhibition ability of Flu and FR against tested tumor cell strains, hence laying the groundwork for reducing the dosage and even the toxic side effects of Flu. As a result of this, the present research not only provides a new strategy for Flu to optimize its physicochemical properties and antitumor activities simultaneously but also offers some opinions for the development of synergistic antitumor pharmaceutical cocrystals.

Cocrystallization with syringic acid presents a new opportunity for effectively reducing the hepatotoxicity of isoniazid.

Objective: With the aim of surmounting the severe hepatotoxicity induced by antituberculosis drug isoniazid (INH), a novel cocrystal of INH with hepatoprotective nutraceutical syringic acid (SYA), namely INH-SYA, was designed and prepared through cocrystallization strategy, which is an intriguing attempt to reduce the toxic side effects of INH.Significance: The study not only provides new thinking for inhibiting toxic side effects of drugs through cocrystallization strategy, but also opens a new pathway for the application of nutraceuticals in the pharmacy.Methods: INH and SYA were successfully crystallized into the same crystal lattice through combining volatilization with solvent assisted methods. The resulting cocrystal was structurally characterized by single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), and differential scanning calorimetry (DSC).Results: The SCXRD analysis for the present cocrystal revealed that it has a 1:1 ratio of INH to SYA with two molecules INH homodimers and two SYA molecules, in which they are arranged alternately linked by hydrogen bonds to form a six molecules ring structure (R66(40)) in crystal. The systematic evaluation of the in vitro/in vivo suggested that, owing to the formation of cocrystal, the dissolution efficiency of SYA was increased 5.85-fold compared with that of coarse SYA, and the oral bioavailability of the cocrystal in rats was enhanced by 3.66 times. As a result, the present INH-SYA cocrystal almost removed INH induced serious hepatotoxicity, which was further demonstrated by the hepatotoxicity studies in rats.Conclusion: INH-SYA cocrystal could effectively reduce the hepatotoxicity of INH.

Synthesis, structure, and biological active evaluation of a new cyclic tetranuclear copper(II) complex bridged both by oxamido and carboxylate groups.

A new tetracopper(II) complex bridged both by oxamido and carboxylato groups, namely [Cu4 (dmaepox)2 (bpy)2 ](NO3 )2 ·2H2 O, where H3 dmaepox and bpy represent N-benzoato-N'- (3-methylaminopropyl)oxamide and 2,2'-bipyridine, was synthesized, and its structure reveals the presence of a centrosymmetric cyclic tetracopper(II) cation assembled by a pair of cis-dmaepox3- - bridged dicopper(II) units through the carboxylato groups, in which the endo- and exo-copper(II) ions bridged by the oxamido group have a square-planar and a square-pyramidal coordination geometries, respectively. The aromatic packing interactions assemble the complex molecules to a two-dimensional supramolecular structure. The reactivity toward DNA and protein bovine serum albumin (BSA) indicates that the complex can interact with herring sperm DNA through the intercalation mode and the binding affinity is dominated by the hydrophobicity and chelate ring arrangement around copper(II) ions and quenches the intrinsic fluorescence of BSA via a static process. The cytotoxicity of the complex shows selective cancer cell antiproliferative activity.

Synthesis and structure of a new trinuclear nickel(II) complex bridged by N-[3-(Dimethylamino)propyl]-N'-(2-hydroxyphenyl)oxamido: in vitro anticancer activities, and reactivities toward DNA and protein.

A new trinickel(II) complex bridged by N-[3-(dimethylamino)propyl]- N'-(2-hydroxylphenyl)oxamido (H3 pdmapo), namely [Ni3 (pdmapo)2 (H2 O)2 ]⋅4CH3 OH, was synthesized and characterized by X-ray single-crystal diffraction and other methods. In the molecule, two symmetric cis-pdmapo3- mononickel(II) complexes as a "complex ligand" using the carbonyl oxygen atoms coordinate to the center nickel(II) ion situated on an inversion point. The Ni···Ni distance through the oxamido bridge is 5.2624(4) Å. The center nickel(II) ion and the lateral ones have octahedral and square-planar coordination geometries, respectively. In the crystal, a three-dimensional supramolecular network dominated by hydrogen bonds is observed. The reactivity toward DNA/protein bovine serum albumin (BSA) revealed that the complex could interact with herring sperm DNA (HS-DNA) through the intercalation mode and quench the intrinsic fluorescence of BSA via a static mechanism. The in vitro anticancer activities suggested that the complex is active against the selected tumor cell lines.

Synthesis, structure, and biological activities of a new µ-oxamido-bridged dicopper(II) complex: the influence of hydrophobicity of bridging ligand on DNA binding and cytotoxic activities.

A new µ-oxamido-bridged dicopper(II) complex, [Cu2 (papo)(H2 O)- (phen)]Cl·CH3 OH·H2 O, where H3 papo and phen represent N-(2-hydroxyphenyl)-N'-(3-aminopropyl)oxamide and 1,10-phenanthroline, respectively, has been synthesized and characterized by elemental analysis, molar conductivity measurement, infrared and electronic spectra studies, and single-crystal X-ray diffraction. The complex crystallizes in the triclinic space group P-1. Each copper(II) ion is located in a slightly distorted square-pyramidal environment. The Cu···Cu distance through the oxamide bridge is 5.1848(7) Å. The three-dimensional supramolecular structure is built-up by hydrogen bonds and π-π stacking interactions. The dicopper(II) complex exhibits cytotoxic activity against the SMMC-7721 and A549 cell lines. The reactivity toward herring sperm DNA and protein bovine serum albumin (BSA) reveals that the dicopper(II) complex can interact with the DNA by the intercalation mode, and effectively quench the intrinsic fluorescence of BSA via a static mechanism. The influence of hydrophobicity of the bridging ligand on DNA-binding properties and in vitro cytotoxic activities of this kind of dicopper(II) complexes was investigated.

Synthesis and Structure of a Ternary Copper(II) Complex with Mixed Ligands of Diethylenetriamine and Picrate: DNA/Protein-Binding Property and In Vitro Anticancer Activity Studies.

Based on the importance of the design and synthesis of transition metal complexes with noncovalent DNA/protein-binding abilities in the field of metallo pharmaceuticals, a new mononuclear ternary copper(II) complex with mixed ligands of diethylenetriamine (dien) and picrate anion (pic), identified as [Cu(dien)(pic)](pic), was synthesized and characterized by elemental analysis, molar conductivity measurement, infrared spectrum, electronic spectral studies, and single-crystal X-ray diffractometry. The structure analysis reveals that the copper(II) complex crystallizes in the monoclinic space group P21 /c, and the copper(II) ion has a distorted square pyramidal coordination geometry. A two-dimensional supramolecular structure is formed through hydrogen bonds. The DNA/bovine serum albumin (BSA)-binding properties of the complex are explored, indicating that the complex can interact with herring sperm DNA via intercalation mode and bind to BSA responsible for quenching of tryptophan fluorescence by static quenching mechanism. The in vitro anticancer activity shows that the copper(II) complex is active against the selected tumor cell lines.

Synthesis and Structure of a New Copper(II) Coordination Polymer Alternately Bridged by Oxamido and Carboxylate Groups: Evaluation of DNA/BSA Binding and Cytotoxic Activities.

A new one-dimensional (1D) copper(II) coordination polymer {[Cu2 (dmaepox)(dabt)](NO3) · 0.5 H2 O}n , where H3 dmaepox and dabt denote N-benzoato-N'-(3-methylaminopropyl)oxamide and 2,2'-diamino-4,4'-bithiazole, respectively, was synthesized and characterized by single-crystal X-ray diffraction and other methods. The crystal structure analysis revealed that the two copper(II) ions are bridged alternately by cis-oxamido and carboxylato groups to form a 1-D coordination polymer with the corresponding Cu · · · Cu separations of 5.1946(19) and 5.038(2) Å. There is a three-dimensional supramolecular structure constructed by hydrogen bonding and π-π stacking interactions in the crystal. The reactivity towards herring sperm DNA (HS-DNA) and bovine serum albumin (BSA) indicated that the copper(II) polymer can interact with the DNA in the mode of intercalation, and bind to BSA responsible for quenching of tryptophan fluorescence by the static quenching mechanism. The in vitro cytotoxicity suggested that the copper(II) polymer exhibits cytotoxic effects against the selected tumor cell lines.

In vitro cytotoxic activities, DNA-, and BSA-binding studies of a new dinuclear copper(II) complex with N-[3-(dimethylamino)propyl]-N'-(2-carboxylatophenyl)-oxamide as ligand.

A new dinuclear copper(II) complex bridged by N-[3-(dimethylamino)propyl]-N'- (2-carbo-xylatophenyl)oxamide (H3 dmapob), and endcapped with 2,2'-diamino-4,4'-bithiazole (dabt), namely [Cu2(dmapob)(dabt)(CH3OH)(pic)]·(DMF)0.75 ·(CH3OH)0.25 has been synthesized and characterized by elemental analysis, molar conductivity measurement, infrared and electronic spectra studies, and single-crystal X-ray diffraction. In the crystal structure, both copper(II) ions have square-pyramidal coordination geometries. The Cu···Cu separation through the oxamido bridge is 5.176(9) Å. A two-dimensional supramolecular framework is formed through hydrogen bonds and π-π stacking interactions. The reactivities toward herring sperm DNA and bovine serum albumin (BSA) show that the complex can interact with the DNA via intercalation mode and bind to the BSA responsible for quenching of tryptophan fluorescence by the static quenching mechanism. The in vitro anticancer activities suggest that the copper(II) complex is active against the selected tumor cell lines. The influence of different bridging ligands in dinuclear complexes on the DNA- and BSA-binding properties as well as anticancer activities is preliminarily discussed.

Bifonazole caffeate: The first molecular salt of bifonazole with enhanced biopharmaceutical property based on experiments and quantum chemistry research.

In order to make novel breakthroughs in molecular salt studies of BCS class-IV antifungal medication bifonazole (BIF), a salification-driven strategy towards ameliorating attributes and aiding augment efficiency is raised. This strategy fully harnesses structural characters together attributes and benefits of caffeic acid (CAF) to concurrently enhance dissolvability and permeability of BIF by introducing the two ingredients into the identical molecular salt lattice through the salification reaction, which, coupled with the aroused potential activity of CAF significantly amplifies the antifungal efficacy of BIF. Guided by this route, the first BIF-organic molecular salt, BIF-CAF, is directionally designed and synthesized with satisfactorily structural characterizations and integrated theoretical and experimental explorations on the pharmaceutical properties. Single-crystal X-ray diffraction resolving confirms that there is a lipid-water amphiphilic sandwich structure constructed by robust charge-assistant hydrogen bonds in the salt crystal, endowing the molecular salt with the potential to enhance both dissolvability and permeability relative to the parent drug, which is validated by experimental evaluations. Remarkably, the comprehensive DFT-based theoretical investigations covering frontier molecular orbital, molecular electrostatic potential, Hirshfeld surface analysis, reduced density gradient, topology, sphericity and planarity analysis strongly support these observations, thereby allowing some positive relationships between macroscopic properties and microstructures of the molecular salt can be made. Intriguingly, the optimal properties, together with the stimulated activity of CAF markedly augment in vitro antifungal ability of the molecular salt, with magnifying inhibition zones and reducing minimum inhibitory concentrations. These findings fill in the gaps on researches of BIF-organic molecular salt, and adequately exemplify the feasibility and validity by integrating theoretical and experimental approaches to resolve BIF's problems via the salification-driven tactic.

Synthesis and crystal structure of binuclear copper(II) complex bridged by N-(2-hydroxyphenyl)-N'-[3-(diethylamino)propyl]oxamide: in vitro anticancer activity and reactivity toward DNA and protein.

A new oxamido-bridged bicopper(II) complex, [Cu2(pdpox)(bpy)(CH3OH)](ClO4), where H3pdpox and bpy stand for N-(2-hydroxyphenyl)-N'-[3-(diethylamino)propyl]oxamide and 2,2'-bipyridine, respectively, has been synthesized and characterized by elemental analyses, molar conductivity measurements, infrared and electronic spectra studies, and X-ray single crystal diffraction. In the crystal structure, the pdpox(3-) ligand bridges two copper(II) ions as cisoid conformation. The inner copper(II) ion has a {N3O} square-planar coordination geometry, while the exo- one is in a {N2O3} square-pyramidal environment. There are two sets of interpenetrating two-dimensional hydrogen bonding networks parallel to the planes (2 1 0) and (21¯0), respectively, to form a three-dimensional supramolecular structure. The bicopper(II) complex exhibits cytotoxic activity against the SMMC7721 and A549 cell lines. The reactivity toward herring sperm DNA and bovine serum albumin revealed that the bicopper(II) complex can interact with the DNA by intercalation mode, and the complex binds to protein BSA responsible for quenching of tryptophan fluorescence by static quenching mechanism.

The first nano-cocrystal formulation of marine drug cytarabine with uracil based on cocrystal nanonization strategy for long-acting injection exhibiting enhanced antitumor activity.

To emphasize the superiority of uracil (UR) in ameliorating biopharmaceutical characteristics of marine antitumor medicine cytarabine (ARA), thus gaining some innovative opinions for the exploitation of nanococrystal formulation, a cocrystal nanonization strategy is proposed by integrating cocrystallization and nanosize preparation techniques. For one thing, based on UR's unique structural features and natures together with advantages of preferential uptake by tumor cells, cocrystallizing ARA with UR is expected to improve the in vitro/vivo performances. For another, the nanonization procedure is oriented towards maintaining the long-term effective drug level. Along this route, a cocrystal of ARA with UR, viz., ARA-UR, is successfully synthesized and then transformed into nano-cocrystal. The cocrystal structure is precisely confirmed by various methods, demonstrating that a 1:1 ARA and UR in the crystal forms cytosine-UR hydrogen-bonding interactions, thus constructing supramolecular frameworks by strong π-π stacking interplays; while the nano-cocrystal is block-shaped particles of 562.70 nm with zeta potential -33.40 mV. The properties of cocrystal ARA-UR and its nano-cocrystal in vitro/vivo are comparatively explored by theoretical calculations and experimental analyses, revealing that permeability of both is significantly increased than ARA per se. Notably, the meliorative natures of both the cocrystal and nano-cocrystal in vitro bring excellent antitumor activity, but the latter has greater strengths over the former. More notably, the nano-cocrystal can sustain effective concentration for a relatively longer time, causing lengthened retention time and better absorption in vivo. The contribution offers a fire-new dosage form of ARA for long-lasting delivery, thus filling the vacancy in nanococrystal studies about marine drugs.

First cocrystal of esculetin: Simultaneously optimized in vitro/vivo properties and antioxidant effect.

Esculetin (ELT) is one of the best-known and simplest coumarins with powerful natural antioxidant effects but insoluble and difficult to absorb. In order to overcome the problems, cocrystal engineering was first applied to ELT in this paper. Nicotinamide (NAM) was selected as the coformer for its excellent water solubility and potential synergistic antioxidant effect with ELT. The structure of the ELT-NAM cocrystal was successfully prepared and characterized by IR, SCXRD, PXRD, and DSC-TG. Furthermore, the in vitro/vivo properties and antioxidant effects of the cocrystal were adequately studied. The results highlight that the ELT obtained tremendous improvements in water solubility and bioavailability after cocrystal formation. Meanwhile, the synergistic enhancement of ELT with NAM in antioxidant effect was demonstrated by the DPPH assay. Ultimately, the simultaneously optimized in vitro/vivo properties and antioxidant activity of the cocrystal created an improved practical effect of hepatoprotective in rat experiments. The investigation is significant for developing coumarin drugs represented by ELT.

Adjuvant activity of Sargassum pallidum polysaccharides against combined Newcastle disease, infectious bronchitis and avian influenza inactivated vaccines.

This study evaluates the effects of Sargassum pallidum polysaccharides (SPP) on the immune responses in a chicken model. The adjuvanticity of Sargassum pallidum polysaccharides in Newcastle disease (ND), infectious bronchitis (IB) and avian influenza (AI) was investigated by examining the antibody titers and lymphocyte proliferation following immunization in chickens. The chickens were administrated combined ND, IB and AI inactivated vaccines containing SPP at 10, 30 and 50 mg/mL, using an oil adjuvant vaccine as a control. The ND, IB and AI antibody titers and the lymphocyte proliferation were enhanced at 30 mg/mL SPP. In conclusion, an appropriate dose of SPP may be a safe and efficacious immune stimulator candidate that is suitable for vaccines to produce early and persistent prophylaxis.

DNA-Binding and Topoisomerase-I-Suppressing Activities of Novel Vanadium Compound Van-7.

Vanadium compounds were studied during recent years to be considered as a representative of a new class of nonplatinum metal anticancer agents in combination to its low toxicity. Here, we found a vanadium compound Van-7 as an inhibitor of Topo I other than Topo II using topoisomerase-mediated supercoiled DNA relaxation assay. Agarose gel electrophoresis and comet assay showed that Van-7 treatment did not produce cleavable complexes like HCPT, thereby suggesting that Topo I inhibition occurred upstream of the relegation step. Further studies revealed that Van-7 inhibited Topo I DNA binding involved in its intercalating DNA. Van-7 did not affect the catalytic activity of DNase I even up to100 µM. Van-7 significantly suppressed the growth of cancer cell lines with IC(50) at nanomolar concentrations and arrested cell cycle of A549 cells at G2/M phase. All these results indicate that Van-7 is a potential selective Topo I inhibitor with anticancer activities as a kind of Topo I suppressor, not Topo I poison.

The first marine dual-drug cocrystal of cytarabine with 5-fluorouracil having synergistic antitumor effects shows superior biopharmaceutical peculiarities by oral administration.

In order to highlight the advantages of cocrystallization technique in perfecting in vitro/vivo natures of marine drug cytarabine (ARC), and fill the gap of the research of marine pharmaceutical cocrystals with synergistic antitumor effects, the first dual-drug cocrystal simultaneously containing ARC and antitumor drug 5-fluorouracil (FU), viz. ARC-FU, is successfully designed and assembled. The accurate structure is perfectly resolved by single-crystal X-ray diffraction and other approaches. The analytical outcomes demonstrate that the codrug cocrystal consists of ARC and FU with a molar ratio of 1:1, in which FU molecule plays an important role by participating in the formation of both "pyrimidine-pyrimidine" and "pyrimidine-sugar" cyclic hydrogen-bonding systems with ARC molecules. In the cocrystal, there are twofold hydrogen-bonding helixes of ARC molecules and a whole three-dimensional hydrogen-bonding network which also contains the aromatic stacking interaction between pyrimidine rings of both components. Such structural feature and aggregation model have crucial influences on the improvements of in vitro/vivo properties, which is methodically verified by the combination of theoretical analyses and experimental measurements. The in vitro studies exhibit the suitably reduced solubility and obviously increased permeability for the cocrystal that is in accord with the theoretical prediction. Importantly, the ameliorated in vitro peculiarities realize in vivo pharmacokinetic optimization including the extended residence time and enhanced relative bioavailability. Of greater significance, ARC exerts synergistic antitumor effects in association with FU that brings about potentiation of cell growth inhibition with lower IC50. Thus, this research not only provides a novel crystalline form for ARC with forward-looking development value, but also breaks new ground for the development of synergistic antitumor pharmaceutical cocrystals with marine characteristics.

5-fluorouracil-caffeic acid cocrystal delivery agent with long-term and synergistic high-performance antitumor effects.

Aim: To explore how to transform cocrystals of the anticancer drug 5-fluorouracil (FL) with caffeic acid (CF; FL-CF-2H2O) into a nanoformulation, a self-assembly strategy of cocrystal-loaded micelles is proposed. Methods: Nanomicelles were assembled to deliver cocrystal FL-CF-2H2O with synergistic activity, and their in vitro/vivo properties were evaluated by combining theoretical and experimental methods. Result: More cocrystal was packed into the polymers due to the stronger interaction energy during micellar assembly, producing excellent cytotoxicity and pharmacokinetic behavior, especially synergistic abilities and long-term therapy. Conclusion: This case exemplifies the particular benefits of the self-assembly strategy of cocrystal-loaded micelles in keeping a delicate balance between long-term effects and high efficiency for FL, and offers a feasible technical scheme for cocrystal delivery agents for antitumor drugs.

To exemplify the feasibility of the cocrystal conversion of anticancer drug 5-fluorouracil (FL) with phenolic acid nutrient caffeic acid (CF) into a nanomicelle formulation, and further provide new options for the development of slowed-release cocrystal formulations with long-acting and synergistic antitumor effects, in this study, a cocrystalline complex of FL and CF (cocrystal FL-CF-2H₂O) was loaded into polymer PEG-PCL to successfully assemble the cocrystal nanomicelles by a self-assembly strategy. The morphology of the cocrystal nanomicelles was characterized, and in vitro/vivo properties were evaluated by combining theoretical with experimental methods. The results showed that the cocrystal nanomicelles with regular sphericity and homogeneous particle size had greater drug loading and entrapment efficiency than FL nanomicelles, which is also supported by theoretical predictions of the interaction energy between the cocrystal FL-CF-2H₂O and polymer PEG-PCL. The excellent encapsulation effects give rise to more potent cytotoxicity, better absorption and prolonged retention time in vivo. Relative to FL nanomicelles, the present cocrystal nanomicelles with synergistic antitumor abilities exhibited prominent slowed-release behavior that was more conducive to the long-term maintenance of therapeutic concentrations in vivo. The present case offers a feasible technical scheme for successful nanoformulation research on synergistic antitumor pharmaceutical cocrystals.