The evaluation of the efficacy of incorporation of quercetin in nanoparticles is crucial, both for the development and quality control of pharmaceutical formulations. The validation of analytical methods for the precise quantification of quercetin is useful for the evaluation of various potential quercetin delivery systems and quercetin pharmacokinetics. This work aimed to validate a high-performance liquid chromatography with diode array detection (HPLC-DAD) method for quercetin detection and quantification in nanoparticles. Different mobile phase conditions and detection wavelengths (254 and 368 nm) were tested, and the major validation parameters were assessed (precision, accuracy, linearity, sensitivity, stability, and selectivity). The best peak resolution was obtained when quercetin was analyzed at 368 nm with a mobile phase of 1.5% acetic acid and a water/acetonitrile/methanol ratio of 55:40:5. Under these conditions, quercetin also eluted rapidly (retention time of 3.6 min). The method proved to be linear (R² > 0.995), specific, and repeatable (variation coefficient between 2.4% and 6.7%) and presented intermediate precision (variation coefficient between 7.2% and 9.4%). The accuracy of the analysis ranged between 88.6% and 110.7%, and detection and quantification limits were 0.046 and 0.14 µg/mL, respectively. Quercetin solutions were more stable when stored at 4 °C than at room temperature or −20 °C. This validated method satisfied more parameters of bias assessment than most recent methods for quercetin determination and presented itself as more sensitive and efficient than general spectrophotometric methods. The method was successfully used for the analysis of quercetin incorporation in nanoparticles and will be evaluated in the future for its adequacy for the determination of quercetin in more complex matrices.

Quercetin (QUE) is the most widely used flavonoid for therapeutic purposes. To improve the available knowledge about the properties of some natural products, determining the amount of QUE is crucial. The main objective of this systematic review is to identify the analytical methods validated for detecting and quantifying QUE in different matrices and characterize their sensitivity. A search was conducted until 30 June 2023 in the PubMed database for experimental studies that addressed the validation of chromatographic analytical methods to detect and quantify QUE from consumable natural products. Only studies published between 2018 and 2022, written in English, were included. The risk of bias was assessed by emphasizing methods of comparison according to previously published studies. Descriptive statistics were used to depict the obtained results. The studies were analyzed based on the type of QUE source, chromatographic method, and validation parameters. A total of 17 studies were included in this review. Plants were the most commonly analyzed source of QUE. Among the detection methods, spectrophotometry proved to be the most widely used, surpassing mass spectrometry (MS). After analyzing the bias, all the included studies mentioned/presented, totally or partially, at least four of the eight parameters.

Background/Objectives: The leakage of 5-fluorouracil (5-FU) from elastomeric infusion pumps used in cancer therapy poses a potential risk of unintentional exposure to multiple individuals, including patients’ relatives and healthcare professionals, and may also compromise the accurate administration of 5-FU dosages to patients. This study aimed to develop, validate, and apply an analytical method to detect and quantify 5-FU residues on the external surfaces of infusion pumps. Methods: A high-performance liquid chromatography with diode-array detection (HPLC-DAD) method was optimized for the quantification of 5-FU contamination across different components of the infusion pump, including the hard casing, infusion tubing, and catheter connection port. A mobile phase containing 5% acetic acid was used to obtain more efficient separation of 5-FU and the detection was performed at 260 nm. The method was evaluated for linearity, sensitivity, precision, accuracy, selectivity, robustness, and stability. Results: The method demonstrated linearity within the range of 0.150 to 3.000 µg/cm², with limits of detection and quantification of 0.05 µg/cm² and 0.14 µg/cm², respectively. Relative standard deviations ranged from 1.8% to 12.7%, and accuracy exceeded 85%. In real sample analysis, detectable residues were found around the catheter connection port. Conclusions: This screening-oriented method addresses an existing gap, as previous contamination reports were based solely on self-reported user observations. The detection of 5-FU residues highlights the critical need for safe handling practices and the consistent use of personal protective equipment (PPE) to protect healthcare workers, especially nursing staff involved in the removal of the infusion pumps, after treatment.

The main function of bladder tissue is urine accumulation and excretion, and it is composed of five layers (mucus layer, epithelial layer, lamina propria, muscular layer, and perivesical tissue). Distinct conditions can compromise morphology and function of the bladder tissue, including congenital disorders, trauma, inflammation and/or cancer. Bladder cancer (BC) is one of the most common genitourinary tract complications, being classified as non-muscle invasive BC (NMIBC) or muscle-invasive BC (MIBC). NMIBC usually affects the mucosa and submucosa of the bladder tissue, requiring tumor resection, followed by intravesical administration of mitomycin-C. MIBC commonly affects the deeper layers of bladder, being associated with the origin of metastases, and it is recommended to perform a radical cystectomy followed by cisplatin-based neoadjuvant chemotherapy. In vitro techniques have been explored as drug screening platforms to test new therapeutic regimens, specifically 3D models that are gaining more attention with a wide range of applications. These 3D structures suitably recreate morphology, complexity and function of bladder tissue or tumor microenvironment (cell-cell and cell-extracellular matrix interactions). Additionally, 3D models represent a useful tool prior to in vivo assays. Different platforms can be developed for closer resembling in vivo urothelial epithelium and bladder tumor, and therefore, for studying tissue and/or tumor morphology, drugs permeability, among others. Following these purposes, 3D bladder models are already being designed, namely spheroids, multilayer models, organ-on-chip, bioprinting, and organoids. Hence, this review aims to highlight and summarize the current advances in the development of 3D in vitro bladder models. STATEMENT OF SIGNIFICANCE: Bladder cancer is classified as NMIBC or MIBC by tissue layer involvement. NMIBC and MIBC are treated with surgery and chemotherapy accordingly. 3D in vitro models accurately mimic bladder tissue and tumor environment. Organoids, spheroids, and hydrogels are established drug screening tools. 3D models show strong potential for translation into clinical applications.