ABSTRACT
OBJECTIVES: To evaluate the combination of more than one release system in the same formulation as a useful strategy to achieve paclitaxel delivery in a more sustained and controlled manner. METHODS: The present study deals with the preparation of poly(lactide-co-glycolide) microparticles loaded with paclitaxel and included in a chitosan thermo-sensitive gelling solution. The microparticles were characterized by their size, shape and drug loading. The formulation was characterized by scanning electron microscopy, in vitro release experiments and was evaluated in mice bearing mammary adenocarcinoma. KEY FINDINGS: The formation of paclitaxel crystals in a pharmaceutical formulation reduces its efficacy. In this work, the use of microparticles avoided this phenomenon. Combining more than one delivery system allowed delivering paclitaxel in a more sustained and controlled manner leading to a long-term effect in the site of action. The formulation showed an inhibition in tumour volume of 63.0% in comparison with the control group. CONCLUSIONS: One intratumour injection of gelling solution containing the microparticles was at least as efficacious as four intraperitoneal injections of a commercial formulation. In addition, the delivery system was nontoxic, and the treated mice presented the highest percentage of tumour regression and median survival time.
Subject(s)
Adenocarcinoma/drug therapy , Antineoplastic Agents, Phytogenic/pharmacology , Chitosan/chemistry , Drug Carriers , Mammary Neoplasms, Animal/drug therapy , Paclitaxel/pharmacology , Polyglactin 910/chemistry , Temperature , Adenocarcinoma/pathology , Animals , Antineoplastic Agents, Phytogenic/chemistry , Chemistry, Pharmaceutical/methods , Delayed-Action Preparations , Drug Compounding , Drug Liberation , Female , Gels , Kinetics , Mammary Neoplasms, Animal/pathology , Mice, Inbred BALB C , Paclitaxel/chemistry , Particle Size , Tumor Burden/drug effectsABSTRACT
The interaction of polymer nanocapsules (NC) prepared from four biodegradable polyesters with variable polymer hydrophobicity (PCL, PLA, PLGA and PLA-PEG) was investigated in the non-phagocytic Vero, Caco-2 and HepG2 cell lines. The NC, labeled with the highly lipophilic fluorescent indocarbocyanine dye DIL, had very similar sizes (approx. 140â¯nm) and negative zeta-potentials. Asymmetric flow field-flow fractionation evidenced NC colloidal stability and negligible transfer of the dye to serum proteins in the incubation medium. The cytotoxicity of the NC was evaluated via MTT assay over a large polymer concentration range (1-1000⯵g/mL) and time of exposure (2, 24 and 48â¯h). The NC were safe in vitro up to a concentration of approx. 100⯵g/mL or higher, depending on the cell line and nature of the polymer. Vero cells were more sensitive to the NC, in particular NC of the more hydrophobic polymer. The cells were exposed to endocytosis inhibitors, incubated with NC, and the cell-associated fluorescence was quantified by spectrofluorometry. HepG2 cells presented a 1.5-2-fold higher endocytic capacity than Caco-2 and Vero cells. The main mechanism of NC uptake was caveolin-mediated endocytosis in HepG2 and Vero cells, and macropinocytosis in Caco-2 cells. Polymer hydrophobicity had an effect on the level of NC associated to HepG2 cells and to a lesser extent on the endocytosis mechanisms in Vero and Caco-2 cells. The NC uptake levels and endocytosis mechanisms differed significantly between cell lines tested.
Subject(s)
Nanocapsules/administration & dosage , Polymers/administration & dosage , Animals , Caco-2 Cells , Chlorocebus aethiops , Endocytosis , Hep G2 Cells , Humans , Hydrophobic and Hydrophilic Interactions , Nanocapsules/chemistry , Polymers/chemistry , Vero CellsABSTRACT
Copolymers of l-lactide and poly(propylene glycol) diglycidyl ether (PPGDGE380) were synthesized by ring opening polymerization (ROP). Stannous octoate was used as the catalyst and 1-dodecanol as the initiator. The effect of the variables on the thermal properties of the copolymers was investigated by differential scanning calorimetry (DSC). Contact angle measurements were made in order to study the wettability of the synthesized copolymers. The copolymers differed widely in their physical characteristics, ranging from weak elastomers to tougher thermoplastics, according to the ratio of l-lactide and PPGDGE380. The results showed that the copolymers were more hydrophilic than neat Poly(lactide) (PLA) and the monomer ratio had a strong influence on the hydrophilic properties.
ABSTRACT
The aim of the study has been to evaluate the morphology, proliferation, and pluripotency maintenance of mouse embryonic stem cells (mESCs) cultivated on poly(lactic-co-glycolic acid) scaffolds. The scaffolds were hydrolyzed with NaOH (treated) and nonhydrolyzed (untreated). Morphological and mechanical characterization of the scaffolds was performed. mESC were evaluated for cell viability, cytotoxicity, expression of pluripotency markers, colony morphology, and overall distribution. The treatment generated a reduction in the hydrophobic characteristics of the scaffolds, leading to a higher wettability compared to the untreated group. The viability, cytotoxicity, number of colonies, and the thickness of the cell layer presented similar results between the scaffold groups. The viability test showed that it was possible to cultivate the mESCs on the scaffolds. The cytotoxicity analysis showed that the PLGA scaffolds were not harmful for the cells. The cells maintained the expression of the pluripotency markers Oct4 and Sox2. The number of colonies and the thickness of the cell layer on the scaffold showed that they were not able to colonize the entire volume of the scaffolds. The area occupied by the mESCs was the same between the treated and untreated groups after 14 days in culture. It is possible to conclude that both conditions are equally suitable for maintaining mESC culture. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 424-432, 2017.
Subject(s)
Cell Proliferation , Materials Testing , Mouse Embryonic Stem Cells/metabolism , Polyglactin 910/chemistry , Tissue Scaffolds/chemistry , Animals , Female , Mice , Mouse Embryonic Stem Cells/cytologyABSTRACT
ABSTRACT The development and validation of a simple and efficient method for the quantification of ferulic acid in poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles coated with chitosan (CS) by reverse phase high performance liquid chromatography coupled to photodiode array detection was described. For the chromatographic analysis, a reverse phase C-18 column was used, mobile phase consisting of acetonitrile and 0.5% acetic acid (37:63, v/v), isocratically eluted at a flow rate of 1 mL/min. Drug determination was performed at 320 nm. The method was validated in terms of the selectivity, linearity, precision, accuracy, robustness, limits of detection and quantification. The method was linear in the range of 10 to 100 µg/mL (r=0.999) and presented limit of detection and quantification of 102 ng/mL and 310 ng/mL, respectively. The method was precise (intra and inter-day) based on relative standard deviation values (less than 3.20%). The recovery was between 101.06 and 102.10%. Robustness was demonstrated considering change in mobile phase proportion. Specificity assay showed no interference from the components of nanoparticles or from the degradation products derived from acidic and oxidative conditions. The proposed method was suitable to be applied in determining the encapsulation efficiency of ferulic acid in PLGA-CS nanoparticles and can be employed as stability indicating one.