Enhanced solubility and self-assembly of amphiphilic sulfasalazine-PEG-OMe (S-PEG) conjugate into core-shell nanostructures useful for colonic drug delivery

Co-amorphous systems of sulfasalazine with matrine-type alkaloids: Enhanced solubility behaviors and synergistic therapeutic potential

Sulfasalazine (SULF), a sulfonamide antibiotic, has been utilized in the treatment of rheumatoid arthritis (RA) and inflammatory bowel disease (IBD) since its discovery. However, its poor water solubility causes the high daily doses (1---3 g) for patients, which may lead to the intolerable toxic and side effects for their lifelong treatment for RA and IBD. In this work, two water-soluble natural anti-inflammatory alkaloids, matrine (MAR) and sophoridine (SPD), were employed to construct the co-amorphous systems of SULF for addressing its solubility issue. These newly obtained co-amorphous forms of SULF were comprehensively characterized by powder X-ray diffraction (PXRD), temperature-modulated differential scanning calorimetry (mDSC), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). We also investigated their dissolution behavior, including powder dissolution, in vitro release, and intrinsic dissolution rate. Both co-amorphous systems exhibited superior dissolution performance compared to crystalline SULF. The underlying mechanism responsible for the enhanced dissolution behaviors in co-amorphous systems were also elucidated. These mechanisms include the inhibition of nucleation, complexation, increased hydrophilicity, and robust intermolecular interactions in aqueous solutions. Importantly, these co-amorphous systems demonstrated satisfactory physical stability under various storage conditions. Network pharmacological analysis was utilized to investigate the potential therapeutic targets of both co-amorphous systems against RA, revealing similar yet distinct multi-target synergistic therapeutic mechanisms in the treatment of this condition. Our study suggests these drug-drug co-amorphous systems hold promise for optimizing SULF dosage in the future and providing a potential drug combination strategy.

Nanoparticle-Based Drug Delivery Systems for Inflammatory Bowel Disease Treatment

Inflammatory bowel disease (IBD) is a chronic, non-specific inflammatory condition characterized by recurring inflammation of the intestinal mucosa. However, the existing IBD treatments are ineffective and have serious side effects. The etiology of IBD is multifactorial and encompasses immune, genetic, environmental, dietary, and microbial factors. The nanoparticles (NPs) developed based on specific targeting methodologies exhibit great potential as nanotechnology advances. Nanoparticles are defined as particles between 1 and 100 nm in size. Depending on their size and surface functionality, NPs exhibit different properties. A variety of nanoparticle types have been employed as drug carriers for the treatment of inflammatory bowel disease (IBD), with encouraging outcomes observed in experimental models. They increase the bioavailability of drugs and enable targeted drug delivery, promoting localized treatment and thus enhancing efficacy. Nevertheless, numerous challenges persist in the translation from nanomedicine to clinical application, including enhanced formulations and preparation techniques, enhanced drug safety profiles, and so forth. In the future, it will be necessary for scientists and clinicians to collaborate in order to study disease mechanisms, develop new drug delivery strategies, and screen new nanomedicines. Nevertheless, numerous challenges persist in the translation from nanomedicine to clinical application, including enhanced formulations and preparation techniques, enhanced drug safety profiles, and so forth. In the future, it will be necessary for scientists and clinicians to collaborate in order to study disease mechanisms, develop new drug delivery strategies, and screen new nanomedicines.

Integrating Nanotechnological Advancements of Disease-Modifying Anti-Rheumatic Drugs into Rheumatoid Arthritis Management

Disease-modifying anti-rheumatic drugs (DMARDs) is a class of anti-rheumatic medicines that are frequently prescribed to patients suffering from rheumatoid arthritis (RA). Methotrexate, sulfasalazine, hydroxychloroquine, and azathioprine are examples of non-biologic DMARDs that are being used for alleviating pain and preventing disease progression. Biologic DMARDs (bDMARDs) like infliximab, rituximab, etanercept, adalimumab, tocilizumab, certolizumab pegol, and abatacept have greater effectiveness with fewer adverse effects in comparison to non-biologic DMARDs. This review article delineates the classification of DMARDs and their characteristic attributes. The poor aqueous solubility or permeability causes the limited oral bioavailability of synthetic DMARDs, while the high molecular weights along with the bulky structures of bDMARDs have posed few obstacles in their drug delivery and need to be addressed through the development of nanoformulations like cubosomes, nanospheres, nanoemulsions, solid lipid nanoparticles, nanomicelles, liposome, niosomes, and nanostructured lipid carrier. The main focus of this review article is to highlight the potential role of nanotechnology in the drug delivery of DMARDs for increasing solubility, dissolution, and bioavailability for the improved management of RA. This article also focusses on the different aspects of nanoparticles like their applications in biologics, biocompatibility, body clearance, scalability, drug loading, and stability issues.

Interaction of sulfasalazine with outer surface of boron-nitride nanotube as a drug carrier in aqueous solution: insights from quantum mechanics and Monte Carlo simulation

The improvement of the solubility of sulfasalazine in physiological media was the major aim of this study. Accordingly, BNNT inspected as a notable candidate for the carriage of this drug in aqueous media. For this purpose, four possible interactions of two tautomer of sulfasalazine with (9,0) boron-nitride nanotube were considered in aqueous media. The compounds were optimized in gas phase using density functional calculations. Solvation free energies and association free energies of the optimized structures were then studied by Monte Carlo simulation and perturbation method in water environment. Outcomes of quantum mechanical calculations presented that interaction of keto form of sulfasalazine produce the most stable complexes with boron-nitride nanotube in gas phase. Simulation results revealed that electrostatic interactions play a vital role in the intermolecular interaction energies after binding of drug and nanotube in aqueous solution. Results of association free energy calculations indicated that complexes of both two sulfasalazine tautomers (keto and enol) and nanotube were stable in solution. Computed solvation free energies in water showed that the interaction with boron-nitride nanotube significantly improved the solubility of sulfasalazine, which could improve its in vivo bioavailability.

Exploring the Crystal Structure Landscape of Sulfasalazine through Various Multicomponent Crystals

Sulfasalazine is used as an anti-inflammatory drug to treat large intestine diseases and atrophic arthritis. In the solid state, two tautomers are known: an amide tautomer (triclinic polymorph) and an imide tautomer (monoclinic polymorph). Crystallization of six new multicomponent solids of sulfasalazine with three cocrystal formers and three salt formers has been achieved by slurry, liquid-assisted grinding and slow evaporation methods. All of the solid forms are characterized by X-ray diffraction techniques, thermal analysis, and Fourier transform infrared spectroscopy. The crystal structural analysis reveals that two sulfasalazine molecules or anions arrange in a head-to-head fashion involving their pyridyl, amide, and sulfonyl groups in an R22(7):R22(8):R22(7) motif. This is the key structural unit appearing in both sulfasalazine imide polymorph and all six multicomponent crystals. In addition, sulfasalazine exists in the amide form in all unsolvated multicomponent crystals obtained in this work and adopts the imide tautomer in the solvated cocrystals and salt. Hirshfeld surface analysis and the associated two-dimensional (2D) fingerprint plots demonstrate that sulfasalazine has significant hydrogen bond donor capability when cocrystallized and is a significant hydrogen bond acceptor in the salts. The frontier molecular orbital analysis indicates that sulfasalazine cocrystals are chemically more stable than the salts.

Emerging Nanotechnologies and Microbiome Engineering for the Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is characterized by the chronic inflammation of the gastrointestinal tract and impacts almost 7 million people across the globe. Current therapeutics are effective in treating the symptoms, but they often do not address the root cause or selectively target areas of inflammation. Notably, self-assembled nanoparticles show great promise as drug delivery systems for the treatment of IBD. Nanoparticles can be designed to survive the harsh gastric conditions and reach inflamed areas of the gastrointestinal tract. Oral drug delivery with nanoparticles can localize drugs to the impacted inflamed region using active and/or passive targeting and promote a high rate of drug dispersion in local tissues, thus reducing potential off-target toxicities. Since a dysregulated gut microbiome is implicated in the development and progression of IBD, it is also important to develop nanoparticles and biomaterials that can restore symbiotic microbes while reducing the proliferation of harmful microbes. In this review, we highlight recent advances in self-assembled nanosystems designed for addressing inflammation and dysregulated gut microbiomes as potential treatments for IBD. Nanoparticles have a promising future in improving the delivery of current therapeutics, increasing patient compliance by providing an oral method of medication, and reducing side effects. However, remaining challenges include scale-up synthesis of nanoparticles, potential side effects, and financial obstacles of clinical trials. It would be in the patients' best interest to continue research on nanoparticles in the pursuit of more effective therapeutics for the treatment of IBD.

Discovery of a Colon-Targeted Azo Prodrug of Tofacitinib through the Establishment of Colon-Specific Delivery Systems Constructed by 5-ASA-PABA-MAC and 5-ASA-PABA-Diamine for the Treatment of Ulcerative Colitis

To mitigate the systemic adverse effects of tofacitinib, 5-ASA-PABA-MAC and 5-ASA-PABA-diamine colon-specific delivery systems were constructed, and tofacitinib azo prodrugs 9 and 20a-20g were synthesized accordingly. The release studies suggested that these systems could effectively release tofacitinib in vitro, and the 5-ASA-PABA-diamine system could successfully realize the colon targeting of tofacitinib in vivo. Specifically, compound 20g displayed a 3.67-fold decrease of plasma AUC_{(tofacitinib, 0-∞)} and a 9.61-fold increase of colonic AUC_{(tofacitinib, 0-12h)}, compared with tofacitinib at a molar equivalent oral dose. Moreover, mouse models suggested that compound 20g (1.5 mg/kg) could achieve roughly the same efficacy against ulcerative colitis compared with tofacitinib (10 mg/kg) and did not impair natural killer cells. These results demonstrated the feasibility of compound 20g as an effective alternative to mitigate the systemic adverse effects of tofacitinib, and 5-ASA-PABA-MAC and 5-ASA-PABA-diamine systems were proven to be effective for colon-specific drug delivery.

Azithromycin-loaded linolenic acid-modified methoxy poly(ethylene glycol) micelles for bacterial infection treatment

In the study, new polymeric micelles loaded with azithromycin were prepared to enhance azithromycin's solubility and evaluate its in vitro/in vivo antibacterial activity against Staphylococcus aureus. Amphiphilic α-Linolenic acid-methoxy poly (ethylene glycol) polymer (MPEG-LNA) was synthesized through DCC-DMAP esterification procedure. Through thin-film hydration method, optimized azithromycin-loaded micelles (AZI-M) were prepared with 87.15% of encapsulation efficiency and 11.07% of drug loading capacity when the ratio of LNA to MPEG was 4. Azithromycin's water-solubility was obviously enhanced due to its loading into the polymeric micelles. The azithromycin-loaded micelles were characterized in terms of x-ray diffraction, Fourier transform infrared spectroscopy, in vitro release, and in vitro/in vivo antibacterial experiments. Although the drug-loaded micelles provided a slow and continuous azithromycin's release in comparison with free azithromycin, in vitro antibacterial activity results confirmed that its effect on the inhibition of bacterial growth and biofilm formation was similar to free azithromycin. It is more interesting that the azithromycin-loaded micelles achieved good in vivo antibacterial therapeutic effect like QiXian® (azithromycin lactobionate injection) in mouse model of intraperitoneal infection. AZI-M can be considered as a potential candidate for in vivo antibiotic therapy of Staphylococcus aureus infections.

A dendritic polyamidoamine supramolecular system composed of pillar[5]arene and azobenzene for targeting drug-resistant colon cancer

Fusobacterium nucleatum caused drug-resistant around tumor sites often leads to the failure of chemotherapy during colorectal cancer (CRC) treatment. Multifunctional cationic quaternary ammonium materials have been widely used as broad-spectrum antibacterial agents in antibacterial and anticancer fields. Herein, we design a smart supramolecular quaternary ammonium nanoparticle, namely quaternary ammonium PAMAM-AZO@CP[5]A (Q-P-A@CP[5]A), consisting of azobenzene (AZO)-conjugated dendritic cationic quaternary ammonium polyamidoamine (PAMAM) as the core and carboxylatopillar[5]arene (CP[5]A)-based switch, for antibacterial and anti-CRC therapies. The quaternary ammonium-PAMAM-AZO (Q-P-A) core endows the supramolecular system with enhanced antibacterial and anticancer properties. -N⁺CH₃ groups on the surface of Q-P-A are accommodated in the CP[5]A cavity under normal conditions, which significantly improves the biocompatibility of Q-P-A@CP[5]A. Meanwhile, the CP[5]A host can be detached from -N⁺CH₃ groups under pathological conditions, achieving efficient antibacterial and antitumor therapies. Furthermore, azoreductase in the tumor site can break the -NN- bonds of AZO in Q-P-A@CP[5]A, leading to the morphology recovery of supramolecular nanoparticles and CRC therapy through inducing cell membrane rupture. Both in vitro and in vivo experiments demonstrate that Q-P-A@CP[5]A possesses good biocompatibility, excellent antibacterial effect, and CRC treatment capability with negligible side effects. This supramolecular quaternary ammonium system provides an effective treatment method to overcome chemotherapy-resistant cancer caused by bacteria.

A self-assembled polymer therapeutic for simultaneously enhancing solubility and antimicrobial activity and lowering serum albumin binding of fusidic acid

The global antimicrobial resistance crisis has prompted worldwide efforts to develop new and more efficient antimicrobial compounds, as well as to develop new drug delivery strategies and targeting mechanisms. This study aimed to synthesize a novel polyethylene glycol-fusidic acid (PEG-FA) conjugate for self-assembly into nano-sized structures and explore its potential for simultaneously enhancing aqueous solubility and antibacterial activity of FA. In addition, the ability of PEG-FA to bind to HSA with lower affinity than FA is also investigated. Haemolysis and in vitro cytotoxicity studies confirmed superior biosafety of the novel PEG-FA compared to FA. The water solubility of FA after PEG conjugation was increased by 25-fold compared to the bare drug. PEG-FA nanoparticles displayed particle size, polydispersity index and zeta potential of 149.3 ± 0.21 nm, 0.267 ± 0.01 and 5.97 ± 1.03 mV, respectively. Morphology studies using high-resolution transmission electron microscope revealed a homogenous spherical shape of the PEG-FA nanoparticles. In silico studies showed that Van der Waals forces facilitated PEG-FA self-assembly. HSA binding studies showed that PEG-FA had very weak or no interaction with HSA using in silico molecular docking (-2.93 kcal/mol) and microscale thermophoresis (K_d=14999 ± 1.36 µM), which may prevent bilirubin displacement. Conjugation with PEG did not inhibit the antibacterial activity of FA but rather enhanced it by 2.5-fold against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus, compared to the bare FA. These results show that PEG-FA can simultaneously enhance solubility and antibacterial activity of FA, whilst also reducing binding of HSA to decrease its side effects.

Bioactivatable reductive cleavage of azobenzene for controlling functional dumbbell oligodeoxynucleotides

Application of stimuli-responsive bioactive molecules is an attractive strategy due to use for target special tissues and cells. Here, we reported synthesis of an azo-linker, 2,2'-dimethoxyl-4,4'-dihydroxymethylazobenzene (mAzo), which was more effectively recognized and cleaved by reducing glutathione (GSH) via comparing with 4,4'-dihydroxymethylazobenzene (Azo). In addition, mAzo is further exploited to engineer dumbbell asODNs, which could result in the release of asODNs and thus modulate their hybridization to target nucleic acids. The present study is the first example to disclose efficient reductive cleavage of azobenzene by GSH to generate aromatic amine. This would provide a valuable strategy for tunable cell-specific release of ODNs and modulation of known disease-causing gene expression in cancer cells.

A review on 5-aminosalicylic acid colon-targeted oral drug delivery systems

Site-specific colon drug delivery is a practical approach for the treatment of local diseases of the colon with several advantages such as rapid onset of action and reduction of the dosage of the drug as well as minimization of harmful side effects. 5-aminosalicylic acid (5-ASA) is a drug of choice in the treatment of inflammatory bowel disease and colitis. For the efficient delivery of this drug, it is vital to prevent 5-ASA release in the upper part of the gastrointestinal tract and to promote its release in the proximal colon. Different approaches including chemical manipulation of drug molecule for production of prodrugs or modification of drug delivery systems using pH-dependent, time-dependent and/or bacterially biodegradable materials have been tried to optimize 5-ASA delivery to the colon. In the current review, the different strategies utilized in the design and development of an oral colonic delivery dosage form of 5-ASA are presented and discussed.