Background: Nabumetone (NAB) is a poorly soluble nonsteroidal anti-inflammatory prodrug (BCS class II drug) whose solubility is significantly improved by complexation with cyclodextrins (CDs). Methods: The solid complexes, in a 1:1 molar ratio, were prepared by mechanochemical activation by grinding, using β-cyclodextrin (β-CD) and its derivatives, hydroxypropyl- and sulfobutylether-β-cyclodextrin (HP-β-CD and SBE-β-CD). The complexation was confirmed by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and attenuated total reflectance Fourier-transformed infrared spectroscopy (ATR–FTIR). Obtained products were further characterized regarding their solubility, in vitro dissolution, permeability and chemical stability. Results: Co-grinding with HP-β-CD and SBE-β-CD yielded products that showed in vitro dissolution profiles in hydrochloric acid medium (pH 1.2) that were substantially different from that of pure NAB, yielding dissolution efficiency enhancements of 34.86 ± 1.64 and 58.30 ± 0.28 times, respectively, for the optimized products. Their in vitro dissolution and gastrointestinal permeability were also studied in a low-volume environment at pH 6.8, corresponding to the intestinal environment. Both β-CD derivatives increased NAB dissolution rate and NAB mass transport across the biomimetic membrane. The effect of β-CD derivatives on NAB chemical stability was studied under the stress conditions by the developed and validated UHPLC–DAD–HRMS method. In acidic conditions, pure and complexed NAB was prone to hydrolytic degradation, yielding one degradation product—pharmacologically inactive NAB metabolite. However, under the oxidative conditions at elevated temperatures, 10 NAB degradation products were identified from co-ground samples. All systems were stable during photo- and long-term stability studies. Conclusions: NAB complexes with HP-β-CD and SBE-β-CD are promising candidates for pharmaceutical product development.

Background: Cinnarizine (CIN) is a poorly soluble drug used in the treatment of vestibular disorders. Its solubility can be improved by complexation with cyclodextrins (CDs). This study focused on the preparation of 1:1 CIN/CD complexes with β-cyclodextrin (βCD) and its derivatives hydroxypropyl-β-cyclodextrin (HPβCD) and sulfobutylether-β-cyclodextrin (SBEβCD) by mechanical activation. Methods: Complexes were obtained under optimized grinding conditions using a high-energy vibrational mill with ZrO₂ grinding media. Solid products were characterized by DSC, TGA, XRPD, and FTIR spectroscopy. Dissolution studies were performed in phosphate buffer (pH 4.5). The effect of βCD and HPβCD on CIN stability was assessed under hydrolytic (acidic, neutral, and basic) and oxidative conditions. A stability-indicating UHPLC-DAD-HRMS method was developed and validated, enabling CIN quantification in the presence of degradation products, whose structures were proposed based on HRMS/MS data. Potential toxicity, bioaccumulation, and mutagenicity of degradation products were predicted using QSAR modeling. Accelerated stability studies (40 °C, 75% RH) were conducted to evaluate long-term stability. Results: Solid-state analyses confirmed CIN/CD interactions in the ground products. The highest dissolution efficiency was observed for CIN/HPβCD complexes, while CD complexation did not alter CIN permeability in biomimetic membrane assays. CIN and its complexes demonstrated satisfactory chemical stability, with no degradation products detected under accelerated conditions. Conclusions: Solid-state complexes of CIN with CDs enhanced dissolution without compromising stability, supporting their potential as promising candidates for novel pharmaceutical formulations.

The complexation of nabumetone (NAB) and naproxen (NAP) with cucurbit[7]uril (CB7) was investigated in aqueous solution by isothermal titration microcalorimetry, mass spectrometry, NMR spectroscopy, and computation methods. High-resolution mass spectrometry was used for the determination of the binding stoichiometry and the gas-phase stability of the drug–CB7 complex. The doubly charged NH₄⁺ or Na⁺ adducts of the 1:1 complex were observed in the mass spectra. The dissociation of complexes was monitored at different collision energies, (1–16) eV, leading to the neutral loss of NH₃ and the drug, with charge retention observed on CB7. By performing ITC experiments, all the thermodynamic parameters were determined for the NAB-CB7 complex in water at 25 °C. The corresponding values amounted to the following: logK = 4.66 ± 0.01; Δ_rG° = −26.7 ± 0.1 kJ/mol; Δ_rH° = −20.2 ± 0.7 kJ/mol; TΔ_rS° = 6.4 ± 0.8 kJ/mol, i.e., the formation of the inclusion complex is enthalpy driven and has a favorable entropy. The inclusion phenomena were further confirmed by NMR spectroscopy (¹H, ROESY, and DOSY), suggesting the encapsulation of the naphthalene ring of both drugs inside the CB7 cavity. The results of the DFT calculations and the IGMH analysis were in accordance with the experimental ones, suggesting that van der Waals interactions play a major role in drug–CB7 complexation.

Advanced oxidation processes (AOPs), including ionizing radiation treatment, are increasingly recognized as an effective method for the degradation of pharmaceutical pollutants, including non-steroidal anti-inflammatory drugs (NSAIDs). Nabumetone (NAB), a widely used NSAID prodrug, poses an environmental risk due to its persistence in aquatic ecosystems and its potential toxicity to non-target organisms. In this study, the radiolytic degradation of NAB was investigated under different experimental conditions (dose rate, radical scavenging, pH, matrix effect), and the toxicity of its degradation products was evaluated. NAB was rapidly degraded at 300 Gy with prolonged irradiation. Mineralization of about 88% of NAB solutions was observed based on the evaluation of total organic carbon (TOC). The most efficient degradation of NAB occurred under N₂O conditions, while it was retarded in the presence of thiourea. The water matrix components had a significant influence on the efficiency of degradation. In addition, the main degradation products were identified by LC-HRMS. Toxicity studies on different bacteria showed no significant impact of the NAB degradation products, while in silico predictive methods revealed their slightly increased toxicity compared to the parent compound, but considerably lower toxicity in comparison to its main active form 6-methoxy-2-naphthylacetic acid (MNA). Additionally, significantly lower toxicities are predicted for degradation products in N₂O saturated solution. These results underline the importance of optimizing irradiation parameters for effective degradation and minimizing the formation of harmful by-products. Understanding all aspects of the AOP processes and the toxicological effects of the degradation products ensures effective mitigation of potential environmental and health risks of water treatment processes.

Discovery of photodegradation pathways for oxazolidine, dioxazepine and ethanolamine facilitates the design of light-triggered self-destruct antibiotics with reduced environmental persistence.