Carboxymethylcellulose biofunctionalized ternary quantum dots for subcellular-targeted brain cancer nanotheranostics

Among the most lethal forms of cancer, malignant brain tumors persist as one of the greatest challenges faced by oncologists, where nanotechnology-driven theranostics can play a critical role in developing novel polymer-based supramolecular nanoarchitectures with multifunctional and multi-modal characteristics to fight cancer. However, it is virtually a consensus that, besides the complexity of active delivering anticancer drugs by the nanocarriers to the tumor site, the current evaluation methods primarily relying on in vitro assays and in vivo animal models have been accounted for the low translational effectiveness to clinical applications. In this view, the chick chorioallantoic membrane (CAM) assay has been increasingly recognized as one of the best preclinical models to study the effects of anticancer drugs on the tumor microenvironment (TME). Thus, in this study, we designed, characterized, and developed novel hybrid nanostructures encompassing chemically functionalized carboxymethylcellulose (CMC) with mitochondria-targeting pro-apoptotic peptide (KLA) and cell-penetrating moiety (cysteine, CYS) with fluorescent inorganic semiconductor (Ag-In-S, AIS) for simultaneously bioimaging and inducing glioblastoma cancer cell (U-87 MG, GBM) death. The results demonstrated that the CMC-peptide macromolecules produced supramolecular vesicle-like nanostructures with aqueous colloidal stability suitable as nanocarriers for passive and active targeting of cancer tumors. The optical properties and physicochemical features of the nanoconjugates confirmed their suitability as photoluminescent nanoprobes for cell bioimaging and intracellular tracking. Moreover, the results in vitro demonstrated a notable killing activity towards GBM cells of cysteine-bearing CMC conjugates coupled with pro-apoptotic KLA peptides. More importantly, compared to doxorubicin (DOX), a model anticancer drug in chemotherapy that is highly toxic, these innovative nanohybrids nanoconjugates displayed higher lethality against U-87 MG cancer cells. In vivo CAM assays validated these findings where the nanohybrids demonstrated a significant reduction of GBM tumor progression (41% area) and evidenced an antiangiogenic activity. These results pave the way for developing polymer-based hybrid nanoarchitectonics applied as targeted multifunctional theranostics for simultaneous imaging and therapy against glioblastoma while possibly reducing the systemic toxicity and side-effects of conventional anticancer chemotherapeutic agents.

Successful growth of fresh retinoblastoma cells in chorioallantoic membrane

The authors developed a retinoblastoma model using fresh harvested cells from an enucleated eye that were transplanted in chick embryos (chorioallantoic membrane model). The transplanted embryos were treated with escalating doses of Melphalan. This exploratory model was developed with the goal of testing drug sensitivity. Our findings suggest this tumor model could be employed to personalize treatment for patients with retinoblastoma, especially those with bilateral and more refractory disease.

Development and chemical characterization of biodegradable polymeric implants containing sirolimus for the treatment of malignant solid tumors

The use of sirolimus and its analogs has been evaluated in studies aimed at combating several types of cancer; however, because of the limited bioavailability of the drug, the search for new forms of administration is required. Biodegradable polymeric implants containing sirolimus were developed and assessed as an alternative method of drug administration. Implants containing 25 % (w/w) sirolimus were prepared employing the polymer matrices chitosan, polycaprolactone and poly(lactic-co-glycolic acid) (PLGA) in two proportions: PLGA 50:50 and PLGA 75:25. Thermal analysis techniques such as thermogravimetry and differential scanning calorimetry, combined with x-ray diffraction were used to characterize and evaluate the compatibility of the constituents of the formulation. No incompatibilities were found between the components, but drug amorphization was observed in all samples. Implants made from the polymers chitosan and PCL may accelerate the degradation of SRL when these polymers are dissolved in methanol at 50 °C. HPLC analysis showed that the implant prepared with PLGA 75:25 did not present degradation products and maintained its appropriate drug content, even when dissolved in methanol and heated to 50 °C. Therefore, it represents the most suitable biodegradable polymer for use in implants developed for the treatment of malignant solid tumors. However, it is still necessary to further study the drug effects after amorphization of the crystal and also to perform stability and solubility analysis.

PLGA Implants containing vancomycin and dexamethasone: development, characterization and bactericidal effects

Post-operative endophthalmitis is an infection and an inflammation of the eye following a surgical procedure. Its treatment is based on drug injections into the eye. However, this treatment can lead to ocular complications. Intraocular implants could substitute the conventional therapy. Poly(lactic-co-glycolic acid) (PLGA) implants comprising on vancomycin and dexamethasone were evaluated as drug delivery system to treat endophthalmitis after cataract surgery. Implants were characterized by drug content uniformity, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Wide Angle X-ray Scattering (WAXS), Scanning Electron Microscopy (SEM) and in vitro drug release. The bactericidal effect of vancomycin, eluted from the implants, was demonstrated against Staphylococcus aureus and Staphylococcus epidermidis. The drugs were uniformly distributed in the polymer. The analytical techniques revealed the chemical integrity of the drugs incorporated into the polymer and the modification of dexamethasone semi-crystalline nature. Drugs were controlled released from implants; and the eluted vancomycin showed bactericidal effects. In conclusion, PLGA implants containing vancomycin and dexamethasone may represent a therapeutic alternative to treat post-operative endophthalmitis.

Analysis of acyclovir in vitreous humor by a validated HPLC method

An HPLC-UV method was developed and validated for the determination of acyclovir in vitreous humor. The method was carried out in isocratic mode using 0.02 mol/L acetic acid/methanol (95:5) as mobile phase, a C18 column at 25 degrees C and UV detection at 254 nm. The method was linear (r2> 0.99) over the range of 35-700 microg/mL, precise (RSD <5%), accurate (recovery ranged from 98.18 to 99.64%), robust, selective regarding of the vitreous humor, and robust remaining unaffected by deliberate variations in relevant parameters. The validated HPLC-UV method can be successfully applied to determine acyclovir directly injected into the vitreous cavity of rabbits' eye.

Safety and Pharmacokinetics of an Intravitreal Biodegradable Implant of Dexamethasone Acetate in Rabbit Eyes

The treatment of vitreoretinal diseases is limited and, nowadays, new drug delivery approaches have been reported in order to increase drug bioavailability. The objective of the current study was to determine the pharmacokinetic profile of a biodegradable dexamethasone acetate implant inserted into the vitreous of rabbits and to evaluate its potential signs of toxicity to the rabbits' eyes. The results showed that the intravitreous drug concentration remained within the therapeutic range along the 8-week period of evaluation. The system under study was not toxic to the normal rabbit retina, and no significant increase in intraocular pressure was observed.

Solid state evaluation of some thalidomide raw materials

Thalidomide presents polymorphism and is a problematic drug due to its poor solubility and difficult tablet processability, which is the dosage form available in Brazil. In most cases, the pharmacopoeias specify do not address solid state characterization of drugs precisely. In this work, different thalidomide commercial samples were characterized by infrared spectroscopy, particle size analysis, scanning electron microscopy, and X-ray diffraction. In addition, the polymorphic forms were quantified for Rietveld analysis and their intrinsic dissolution rates were evaluated. The results demonstrated the market availability of different raw materials which lack of homogeneity due to differences related to crystalline constitution, crystal habit and intrinsic dissolution rate.