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Background/Objectives: In addition to oncological applications, poly(ADP-ribose) polymerase (PARP) inhibitors have potential as anti-inflammatory agents. Colon-targeted delivery of PARP inhibitors has been evaluated as a pharmaceutical strategy to enhance their safety and therapeutic efficacy against gut inflammation. Methods: Colon-targeted PARP inhibitors 5-aminoisoquinoline (5-AIQ) and 3-aminobenzamide (3-AB) were designed and synthesized by azo coupling with salicylic acid (SA), yielding 5-AIQ azo-linked with SA (AQSA) and 3-AB azo-linked with SA (ABSA). Additional conjugation of AQSA with acidic amino acids yielded glutamic acid-conjugated AQSA (AQSA-Glu) and aspartic acid-conjugated AQSA, which further increased the hydrophilicity of AQSA. Results: The distribution coefficients of PARP inhibitors were lowered by chemical modifications, which correlated well with drug permeability via the Caco-2 cell monolayer. All derivatives were effectively converted to their corresponding PARP inhibitors in the cecal contents. Compared with observations in the oral administration of PARP inhibitors, AQSA-Glu and ABSA resulted in the accumulation of much greater amounts of each PARP inhibitor in the cecum. ABSA accumulated mesalazine (5-ASA) in the cecum to a similar extent as sulfasalazine (SSZ), a colon-targeted 5-ASA prodrug. In the DNBS-induced rat colitis model, AQSA-Glu enhanced the anticolitic potency of 5-AIQ. Furthermore, ABSA was more effective against rat colitis than SSZ or AQSA-Glu, and the anticolitic effects of AQSA-Glu were augmented by combined treatment with a colon-targeted 5-ASA prodrug. In addition, the colon-targeted delivery of PARP inhibitors substantially reduced their systemic absorption. Conclusions: Colon-targeted PARP inhibitors may improve the therapeutic and toxicological properties of inhibitors and synergize the anticolitic effects of 5-ASA. [ABSTRACT FROM AUTHOR]

Background/Objectives: Owing to the growing resistance of methicillin-resistant Staphylococcus aureus (MRSA) to conventional antibiotics, the development of innovative therapeutic strategies for the treatment of MRSA-infected cutaneous wounds poses a significant challenge. Methods: Here, by using polyhydroxyalkanoates (PHA), emerging biodegradable and biocompatible polymers naturally produced by various microorganisms, we developed clindamycin-loaded PHA nanoparticles (Cly-PHA NPs) as a novel approach for the treatment of MRSA-infected cutaneous wounds. Results: Cly-PHA NPs were characterized in terms of mean particle size (216.2 ± 38.9 nm), polydispersity index (0.093 ± 0.03), zeta potential (11.3 ± 0.5 mV), and drug loading (6.76 ± 0.19%). Owing to the sustained release of clindamycin over 2 days provided by the PHA, Cly-PHA NPs exhibited potent antibacterial effects against MRSA. Furthermore, Cly-PHA NPs significantly facilitated wound healing in a mouse model of MRSA-infected full-thickness wounds by effectively eradicating MRSA from the wound bed. Conclusions: Therefore, our results suggest that Cly-PHA NPs offer a promising approach for combating MRSA infections and accelerating cutaneous wound healing. [ABSTRACT FROM AUTHOR]

In our previous study, riluzole azo-linked to salicylic acid (RAS) was prepared as a colon-targeted prodrug of riluzole (RLZ) to facilitate the repositioning of RLZ as an anticolitic drug. RAS is more effective against rat colitis than RLZ and sulfasalazine, currently used as an anti-inflammatory bowel disease drug. The aim of this study is to further improve colon specificity, anticolitic potency, and safety of RAS. N-succinylaspart-1-ylRLZ (SAR) and N-succinylglutam-1-ylRLZ (SGR) were synthesized and evaluated as a "me-better" colon-targeted prodrug of RLZ against rat colitis. SAR but not SGR was converted to RLZ in the cecal contents, whereas both conjugates remained intact in the small intestine. When comparing the colon specificity of SAR with that of RAS, the distribution coefficient and cell permeability of SAR were lower than those of RAS. In parallel, oral SAR delivered a greater amount of RLZ to the cecum of rats than oral RAS. In a DNBS-induced rat model of colitis, oral SAR mitigated colonic damage and inflammation and was more potent than oral RAS. Moreover, upon oral administration, SAR had a greater ability to limit the systemic absorption of RLZ than RAS, indicating a reduced risk of systemic side effects of SAR. Taken together, SAR may be a "me-better" colon-targeted prodrug of RLZ to improve the safety and anticolitic potency of RAS, an azo-type colon-targeted prodrug of RLZ. [ABSTRACT FROM AUTHOR]

Alizarin (1,2‐dihydroxyanthraquinone) is an anthraquinone reddish dye widely used for painting and textile dyeing. As the biological activity of alizarin has recently attracted increasing attention from researchers, its therapeutic potential as complementary and alternative medicine is of interest. However, no systematic research has been conducted on the biopharmaceutical and pharmacokinetic aspects of alizarin. Therefore, this study aimed to comprehensively investigate the oral absorption and intestinal/hepatic metabolism of alizarin using a simple and sensitive tandem mass spectrometry method developed and validated in‐house. The present method for the bioanalysis of alizarin has merits, including a simple pretreatment procedure, small sample volume, and adequate sensitivity. Alizarin exhibited pH‐dependent moderate lipophilicity and low solubility with limited intestinal luminal stability. Based on the in vivo pharmacokinetic data, the hepatic extraction ratio of alizarin was estimated to be 0.165–0.264, classified as a low level of hepatic extraction. In an in situ loop study, considerable fractions (28.2%–56.4%) of the alizarin dose were significantly absorbed in gut segments from the duodenum to ileum, suggesting that alizarin may be classified as the Biopharmaceutical Classification System class II. An in vitro metabolism study using rat and human hepatic S9 fractions revealed that glucuronidation and sulfation, but not NADPH‐mediated phase I reactions and methylation, are significantly involved in the hepatic metabolism of alizarin. Taken together, it can be estimated that the fractions of oral alizarin dose unabsorbed from the gut lumen and eliminated by the gut and liver before reaching the systemic circulation are 43.6%–76.7%, 0.474%–36.3%, and 3.77%–5.31% of the dose, respectively, resulting in a low oral bioavailability of 16.8%. Therefore, the oral bioavailability of alizarin depends primarily on its chemical degradation in the gut lumen and secondarily on first‐pass metabolism. [ABSTRACT FROM AUTHOR]

The gut microbiome is closely linked to gastrointestinal health and disease status. Oral administration of known probiotic strains is now considered a promising therapeutic strategy, especially for refractory diseases such as inflammatory bowel disease. In this study, we developed a nanostructured hydroxyapatite/alginate (HAp/Alg) composite hydrogel that protects its encapsulated probiotic Lactobacillus rhamnosus GG (LGG) by neutralizing hydrogen ions that penetrate the hydrogel in a stomach without inhibiting LGG release in an intestine. Surface and transection analyses of the hydrogel revealed characteristic patterns of crystallization and composite‐layer formation. TEM revealed the dispersal of the nanosized HAp crystals and encapsulated LGG in the Alg hydrogel networks. The HAp/Alg composite hydrogel maintained its internal microenvironmental pH, thereby enabling the LGG to survive for substantially longer. At intestinal pH, the encapsulated LGG was completely released upon disintegration of the composite hydrogel. In a dextran sulfate sodium‐induced colitis mouse model, we then assessed the therapeutic effect of the LGG‐encapsulating hydrogel. This achieved intestinal delivery of LGG with minimal loss of enzymatic function and viability, ameliorating colitis by reducing epithelial damage, submucosal edema, inflammatory cell infiltration, and the number of goblet cells. These findings reveal the HAp/Alg composite hydrogel as a promising intestinal‐delivery platform for live microorganisms including probiotics and live biotherapeutic products. [ABSTRACT FROM AUTHOR]

N‐Acetylserotonin (NAS) is an intermediate in the melatonin biosynthetic pathway. We investigated the anti‐inflammatory activity of NAS by focusing on its chemical feature oxidizable to an electrophile. NAS was readily oxidized by reaction with HOCl, an oxidant produced in the inflammatory state. HOCl‐reacted NAS (Oxi‐NAS), but not NAS, activated the anti‐inflammatory nuclear factor erythroid 2‐related factor 2 (Nrf2)‐heme oxygenase (HO)‐1 pathway in cells. Chromatographic and mass analyses demonstrated that Oxi‐NAS was the iminoquinone form of NAS and could react with N‐acetylcysteine possessing a nucleophilic thiol to form a covalent adduct. Oxi‐NAS bound to Kelch‐like ECH‐associated protein 1, resulting in Nrf2 dissociation. Moreover, rectally administered NAS increased the levels of nuclear Nrf2 and HO‐1 proteins in the inflamed colon of rats. Simultaneously, NAS was converted to Oxi‐NAS in the inflamed colon. Rectal NAS mitigated colonic damage and inflammation. The anticolitic effects were significantly compromised by the coadministration of an HO‐1 inhibitor. [ABSTRACT FROM AUTHOR]

We designed colon-targeted trans-cinnamic acid (tCA) and synthesized its conjugates with glutamic acid (tCA-GA) and aspartic acid (tCA-AA). We evaluated the anti-colitic activity of colon-targeted tCA using a dinitrobenzenesulfonic acid-induced rat colitis model. The conjugates lowered the distribution coefficient and Caco-2 cell permeability of tCA and converted to tCA in the cecum, with higher rates and percentages with tCA-GA than with tCA-AA. Following oral gavage, tCA-GA delivered a higher amount of tCA to the cecum and exhibited better anti-colitic effects than tCA and sulfasalazine (SSZ), which is the current treatment for inflammatory bowel disease. In the cellular assay, tCA acted as a full agonist of GPR109A (EC50: 530 µM). The anti-colitic effects of tCA-GA were significantly compromised by the co-administration of the GPR109A antagonist, mepenzolate. Collectively, colon-targeted tCA potentiated the anti-colitic activity of tCA by effectively activating GPR109A in the inflamed colon, enabling tCA to elicit therapeutic superiority over SSZ. [ABSTRACT FROM AUTHOR]