Gustavo Henrique Rodrigues da Silva

Glucose-6-phosphate dehydrogenase (G6PDH), the first enzyme of the oxidative pentose phosphate pathway, is essential for redox homeostasis in trypanosomatids, making it an attractive target. Here, we synthesized and evaluated a new series of non-steroidal dihydroquinazolinone derivatives against Trypanosoma cruzi G6PDH (TcG6PDH). Biochemical profiling revealed clear quantitative (QSAR) and structure–activity relationships (SAR); increasing halogen size on the aniline moiety enhanced enzymatic potency. The iodinated analogue 26 displayed submicromolar inhibition (IC50 = 0.12 µM) and nearly 200-fold selectivity over human G6PDH, though its enzymatic potency did not translate into antiparasitic efficacy, likely due to intracellular exposure limitations. Conversely, compound 17 exhibited the most balanced phenotypic profile, combining selective TcG6PDH inhibition with potent activity against epimastigotes and intracellular amastigotes (EC50 = 2.59 µM) without host cytotoxicity. In vitro ADME characterization of 17 revealed a potential solubility liability under neutral conditions but demonstrated high membrane permeability in both cellular and artificial barrier models. However, 17 failed to reduce parasitemia or tissue parasite burden in an acute murine model of Chagas disease. Pharmacological scaling using the well-stirred liver model reconciled this in vivo failure, identifying a critical combination of rapid microsomal metabolic clearance (t1/2 = 7 min in mouse) and high plasma protein binding (97.2%), which severely restricted the free, bioactive fraction (fu = 2.8%) in circulation. These findings expand the SAR and QSAR landscape of dihydroquinazolinone-based antitrypanosomal agents and demonstrate that future optimization must balance enzymatic potency with heterocyclic bioisosteric modifications to overcome metabolic susceptibility and plasma protein binding liabilities.

Chronic kidney disease (CKD) is characterized by systemic metabolic disturbances and oxidative stress. Nutritional interventions using bioactive compounds such as sulforaphane (SFN) may represent a promising adjuvant strategy to attenuate these alterations. This study evaluated the effects of SFN supplementation on the untargeted metabolomic profile of non-dialysis CKD patients. A randomized, placebo-controlled clinical trial was conducted in 14 patients with CKD stages 3–5 who received either 400 µg per day of SFN or placebo for 30 days. Serum samples were analyzed using proton nuclear magnetic resonance (¹H NMR) spectroscopy to identify metabolomic alterations and their correlations with markers of oxidative stress, inflammation, and gene expression. SFN supplementation tended to reduce 2-hydroxyisovalerate and glycerol levels, metabolites associated with insulin resistance and oxidative stress, and attenuated methanol elevation. Correlations were identified between heme oxygenase-1 (HO-1) and several amino acids, and between NRF2 and glycerol, suggesting an interplay between amino acid metabolism and antioxidant defense. Overall, SFN modulated the metabolomic profile of CKD patients, particularly metabolites related to mitochondrial function, lipid metabolism, and oxidative balance. These findings demonstrate that NMR-based metabolomics is a powerful non-invasive approach for elucidating the molecular effects of nutritional therapies in CKD and support SFN as a potential nutraceutical strategy in renal care.

Although chemotherapy regimens are well-established in clinical practice, chemoresistance and adverse side effects pose significant obstacles in cancer treatment. Paclitaxel (PTX), a widely used chemotherapeutic agent, faces formulation challenges due to its poor solubility and permeability. Research suggests that the phytochemical Cannabidiol (CBD) holds potential not only in targeting cancer cells but also in alleviating pain and nausea, thereby improving the quality of life for cancer patients. However, CBD’s clinical application is also limited by its poor solubility, low bioavailability, and susceptibility to oxidation. Nanostructured lipid carriers (NLCs) represent a promising drug delivery system for hydrophobic compounds like PTX and CBD and allow their coencapsulation. Nonetheless, achieving a stable formulation requires the identification of suitable preparation methods and excipients. The aim of this study was to develop and optimize an NLC formulation for the coencapsulation of PTX and CBD. Using factorial design, an optimized formulation was obtained with homogeneous particle sizes (200 nm), negative ZPs (−16.1 mV), a particle concentration of 10¹³ particles/mL, spherical morphology (TEM images), and a lipid core with low crystallinity (confirmed by XRD). To evaluate the therapeutic potential of the drug combination, cell viability assays were conducted on murine melanoma cells (B16–F10) at different exposure times (24 and 48 h). The NLC–CBD-PTX formulation significantly reduced cell viability in a time- and concentration-dependent manner, demonstrating at least 75% greater activity at 24 h compared to each drug individually, whether free (PTX, CBD) or encapsulated (NLC-PTX, NLC–CBD). This indicates a synergistic effect between CBD and PTX when coencapsulated, particularly at higher concentrations and shorter exposure times. In conclusion, an innovative pharmaceutical formulation coencapsulating PTX and CBD was validated, showing potential to enhance antitumor efficacy, overcome chemoresistance, reduce side effects, and broaden therapeutic applications. The resulting NLCs exhibited favorable physicochemical properties, supporting their suitability for various routes of administration.

Recent studies have highlighted the potential of local anesthetics (LA) as adjuvants in cancer treatment, specifically by increasing survival rates when used in surgical excisions. However, the clinical use of LA is restricted due to their systemic toxicity. The development of drug delivery systems could address this issue and advance the utilization of these molecules. In this research, we explored the pharmacokinetics (using microdialysis probes) and antitumor properties of a nanostructured lipid carrier (NLC) formulation containing the commercially available enantiomeric excess form of bupivacaine (BVC_S75). This NLC was prepared with lavender oil (NLC-L-BVC), an excipient with inherent antitumor properties. We compared this formulation to a control (NLC-BVC) using synthetic lipids. Pharmacokinetic assessments of the NLCs confirmed the sustained release of BVC_S75 within the tumor, characterized by a reduced elimination rate constant and longer half-life (∼6×). The encapsulation of BVC_S75 within nanoparticles (whether natural or synthetic) enhanced its effectiveness in treating the primary tumor, resulting in the inhibition of tumor growth (70% with NLC-L-BVC and 72% with NLC-BVC), outperforming free BVC (17% inhibition). However, the association of lavender oil with BVC_S75 in an NLC did not yield synergistic properties. Furthermore, all BVC_S75 treatments (whether free or encapsulated) improved animal survival rates. These findings confirm that encapsulation of bupivacaine in NLC can prolong drug action at the local site, contributing to improved local antitumor therapy while mitigating systemic effects.

Although chemotherapy regimens are well-established in clinical practice, chemoresistance and adverse side effects pose significant obstacles in cancer treatment. Paclitaxel (PTX), a widely used chemotherapeutic agent, faces formulation challenges due to its poor solubility and permeability. Research suggests that the phytochemical Cannabidiol (CBD) holds potential not only in targeting cancer cells but also in alleviating pain and nausea, thereby improving the quality of life for cancer patients. However, CBD’s clinical application is also limited by its poor solubility, low bioavailability, and susceptibility to oxidation. Nanostructured lipid carriers (NLCs) represent a promising drug delivery system for hydrophobic compounds like PTX and CBD and allows their co-encapsulation. Nonetheless, achieving a stable formulation requires identifying suitable preparation methods and excipients. The aim of this study was to develop and optimize an NLC formulation for the co-encapsulation of PTX and CBD. Using factorial design, an optimized formulation was obtained with homogeneous particle sizes (200 nm), negative zeta potentials (−17 mV), particle concentration of 10 ¹³ particles/mL, spherical morphology (TEM images), and a lipid core with low crystallinity (as confirmed by XRD). To evaluate the therapeutic potential of the drug combination, cell viability assays were conducted on murine melanoma cells (B16-F10) at different exposure times (24 and 48 hours). The NLC-CBD-PTX formulation significantly reduced cell viability in a time- and concentration-dependent manner, demonstrating at least 75% greater activity at 24 hours compared to each drug individually whether free (PTX, CBD) or encapsulated (NLC-PTX, NLC-CBD). This indicates a synergistic effect of the encapsulated drugs on cytotoxicity. In conclusion, an innovative pharmaceutical formulation co-encapsulating PTX and CBD was validated, showing potential to enhance antitumor efficacy, overcome chemoresistance, reduce side effects, and broaden therapeutic applications. The resulting NLCs exhibited favorable physicochemical properties, supporting their suitability for various routes of administration.

Unsuccessful anesthesia often occurs under an inflammatory tissue environment, making dentistry treatment extremely painful and challenging. Articaine (ATC) is a local anesthetic used at high (4%) concentrations. Since nanopharmaceutical formulations may improve the pharmacokinetics and pharmacodynamics of drugs, we encapsulated ATC in nanostructured lipid carriers (NLCs) aiming to increase the anesthetic effect on the inflamed tissue. Moreover, the lipid nanoparticles were prepared with natural lipids (copaiba (Copaifera langsdorffii) oil and avocado (Persia gratissima) butter) that added functional activity to the nanosystem. NLC-CO-A particles (~217 nm) showed an amorphous lipid core structure according to DSC and XDR. In an inflammatory pain model induced by λ-carrageenan in rats, NLC-CO-A improved (30%) the anesthetic efficacy and prolonged anesthesia (3 h) in relation to free ATC. In a PGE2-induced pain model, the natural lipid formulation significantly reduced (~20%) the mechanical pain when compared to synthetic lipid NLC. Opioid receptors were involved in the detected analgesia effect since their blockage resulted in pain restoration. The pharmacokinetic evaluation of the inflamed tissue showed that NLC-CO-A decreased tissue ATC elimination rate (ke) by half and doubled ATC’s half-life. These results present NLC-CO-A as an innovative system to break the impasse of anesthesia failure in inflamed tissue by preventing ATC accelerated systemic removal by the inflammatory process and improving anesthesia by its association with copaiba oil.

Breast cancer is the neoplasia of highest incidence in women worldwide. Docetaxel (DTX), a taxoid used to treat breast cancer, is a BCS-class-IV compound (low oral bioavailability, solubility and intestinal permeability). Nanotechnological strategies can improve chemotherapy effectiveness by promoting sustained release and reducing systemic toxicity. Nanostructured lipid carriers (NLC) encapsulate hydrophobic drugs in their blend-of-lipids matrix, and imperfections prevent drug expulsion during storage. This work describes the preparation, by design of experiments (2³ factorial design) of a novel NLC formulation containing copaiba oil (CO) as a functional excipient. The optimized formulation (NLC_DTX) showed approximately 100% DTX encapsulation efficiency and was characterized by different techniques (DLS, NTA, TEM/FE-SEM, DSC and XRD) and was stable for 12 months of storage, at 25 °C. Incorporation into the NLC prolonged drug release for 54 h, compared to commercial DTX (10 h). In vitro cytotoxicity tests revealed the antiproliferative effect of CO and NLC_DTX, by reducing the cell viability of breast cancer (4T1/MCF-7) and healthy (NIH-3T3) cells more than commercial DTX. NLC_DTX thus emerges as a promising drug delivery system of remarkable anticancer effect, (strengthened by CO) and sustained release that, in clinics, may decrease systemic toxicity at lower DTX doses.