Effect of different formulation variables on some particle characteristics of poly (DL-lactide-co-glycolide) nanoparticles

Ferri-Liposomes: Preformulation and Selective Cytotoxicity against A549 Lung Cancer Cells

Liposomes have become successful nanostructured systems used in clinical practices. These vesicles are able to carry important drug loadings with noteworthy stability. The aim of this work was to develop iron oxide-loaded stealth liposomes as a prospective alternative for the treatment of lung cancer. In this study, citric acid iron oxide nanoparticles (IONPs-Ac) were synthesized and encapsulated in stealth liposomes. Their cytotoxicity and selectivity against lung tumor cells were assessed. Stealth liposomal vesicles, with relevant content of IONPs-Ac, named ferri-liposomes (SL-IONPs-Ac), were produced with an average size of 200 nm. They displayed important cytotoxicity in a human lung cancer cells model (A549 cells), even at low concentrations, whereas free IONPs-Ac displayed adequate biocompatibility. Nevertheless, the treatment at the same concentration of ferri-liposomes against HEK-293 cells, a normal human cell lineage, was not significantly cytotoxic, revealing a probable lung tumor selectiveness of the fabricated formulation. Furthermore, from the flow cytometry studies, it was possible to infer that ferri-liposomes were able to induce A549 tumor cells death through apoptosis/ferroptosis processes, evidenced by a significant reduction of the mitochondrial membrane potential.

Optimising poly(lactic-co-glycolic acid) microparticle fabrication using a Taguchi orthogonal array design-of-experiment approach

The objective of this study was to identify, understand and generate a Taguchi orthogonal array model for the formation of 10-50 μm microparticles with applications in topical/ocular controlled drug delivery. Poly(lactic-co-glycolic acid) (PLGA) microparticles were fabricated by the single emulsion oil-in-water method and the particle size was characterized using laser diffraction and scanning electronic microscopy (SEM). Sequential Taguchi L12 and L18 orthogonal array (OA) designs were employed to study the influence of ten and eight parameters, respectively, on microparticle size (response). The first optimization step using the L12 design showed that all parameters significantly influenced the particle size of the prepared PLGA microparticles with exception of the concentration of poly(vinyl alcohol) (PVA) in the hardening bath. The smallest mean particle size obtained from the L12 design was 54.39 μm. A subsequent L18 design showed that the molecular weight of PLGA does not significantly affect the particle size. An experimental run comprising of defined parameters including molecular weight of PLGA (89 kDa), concentration of PLGA (20% w/v), concentration of PVA in the emulsion (0.8% w/v), solvent type (ethyl acetate), organic/aqeuous phase ratio (1:1 v/v), vortexing speed (9), vortexing duration (60 seconds), concentration of PVA in hardening bath (0.8% w/v), stirring speed of hardening bath (1200 rpm) and solvent evaporation duration (24 hours) resulted in the lowest mean particle size of 23.51 μm which was predicted and confirmed by the L18 array. A comparable size was demonstrated during the fabrication of BSA-incorporated microparticles. Taguchi OA design proved to be a valuable tool in determining the combination of process parameters that can provide the optimal condition for microparticle formulation. Taguchi OA design can be used to correctly predict the size of microparticles fabricated by the single emulsion process and can therefore, ultimately, save time and costs during the manufacturing process of drug delivery formulations by minimising experimental runs.

New Trends on Antineoplastic Therapy Research: Bullfrog (Rana catesbeiana Shaw) Oil Nanostructured Systems

Bullfrog oil is a natural product extracted from the Rana catesbeiana Shaw adipose tissue and used in folk medicine for the treatment of several diseases. The aim of this study was to evaluate the extraction process of bullfrog oil, to develop a suitable topical nanoemulsion and to evaluate its efficacy against melanoma cells. The oil samples were obtained by hot and organic solvent extraction processes and were characterized by titration techniques and gas chromatography mass spectrometry (GC-MS). The required hydrophile-lipophile balance and the pseudo-ternary phase diagram (PTPD) were assessed to determine the emulsification ability of the bullfrog oil. The anti-tumoral activity of the samples was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay for normal fibroblast (3T3) and melanoma (B16F10) cell lines. Both extraction methods produced yielded around 60% and the oil was mainly composed of unsaturated compounds (around 60%). The bullfrog oil nanoemulsion obtained from PTPD presented a droplet size of about 390 nm and polydispersity = 0.05 and a zeta potential of about -25 mV. Both the bullfrog oil itself and its topical nanoemulsion did not show cytotoxicity in 3T3 linage. However, these systems showed growth inhibition in B16F10 cells. Finally, the bullfrog oil presented itself as a candidate for the development of pharmaceutical products free from cytotoxicity and effective for antineoplastic therapy.

Resveratrol-loaded nanocarriers: formulation, optimization, characterization and in vitro toxicity on cochlear cells

The present work aimed to investigate the suitability of polymeric nanoparticles (NPs) loaded with resveratrol (RES) for drug delivery to cochlear cells. RES-loaded NPs were prepared by a solvent-diffusion method without surfactant. The Box-Behnken design was used to study the effect of the formulation variables on the particle mean diameter (PMD), polydispersity index (PDI), zeta-potential (ζ), percent drug encapsulation efficiency (EE%), and ratio between NP size before and after freeze-drying (Sf/Si). The physicochemical stability of the RES-loaded NPs during freeze-drying was investigated using four well-known cryoprotectants (i.e., lactose, mannitol, sucrose, and trehalose) at different concentrations. The RES-loaded NPs were also characterized by powder X-ray diffraction (PXRD) and in vitro drug release studies. Finally, the in vitro toxicity of the synthesized NPs was evaluated on two cochlear cell lines: HEI-OC1 and SVK-1 cells. The optimal formulation (desirability: 0.86) had 135.5±37.3nm as PMD, 0.126±0.080 as PDI, -26.84±3.31mV as ζ, 99.83±17.59% as EE%, and 3.30±0.92 as Sf/Si ratio. The PMD and PDI of the RES-loaded NPs were maintained within the model space only when trehalose was used at concentrations higher than 15% (w/v). Results from the in vitro cytotoxicity studies showed that blank NPs did not alter the viability of both cells lines, except for concentrations higher than 600μg/mL. However, the cell viability was significantly decreased at high concentrations of native RES (>50μM, p<0.05) in both cell lines. Overall, the results suggested that the RES-loaded polymeric NPs could be a suitable template for cochlea antioxidant delivery and otoproctection.