ABSTRACT
OBJECTIVES: The objective of this study was to investigate the efficiency of uptake of PEGylated polylactide-co-gycolide (PLGA) nanoparticles by breast cancer cells. METHODS: Nanoparticles of PLGA containing various amounts of polyethylene glycol (PEG, 5%-15%) were prepared using a double emulsion solvent evaporation method. The nanoparticles were loaded with coumarin-6 (C6) as a fluorescence marker. The particles were characterized for surface morphology, particle size, zeta potential, and for cellular uptake by 4T1 murine breast cancer cells. KEY FINDINGS: Irrespective of the amount of PEG, all formulations yielded smooth spherical particles. However, a comparison of the particle size of various formulations showed bimodal distribution of particles. Each formulation was later passed through a 1.2 µm filter to obtain target size particles (114-335 nm) with zeta potentials ranging from -2.8 mV to -26.2 mV. While PLGA-PEG di-block (15% PEG) formulation showed significantly higher 4T1 cellular uptake than all other formulations, there was no statistical difference in cellular uptake among PLGA, PLGA-PEG-PLGA tri-block (10% PEG), PLGA-PEG di-block (5% PEG) and PLGA-PEG di-block (10% PEG) nanoparticles. CONCLUSION: These preliminary findings indicated that the nanoparticle formulation prepared with 15% PEGylated PLGA showed maximum cellular uptake due to it having the smallest particle size and lowest zeta potential.
Subject(s)
Biocompatible Materials/chemistry , Coumarins/pharmacokinetics , Drug Carriers , Lactic Acid/chemistry , Nanoparticles/chemistry , Polyglycolic Acid/chemistry , Sulfhydryl Compounds/pharmacokinetics , Animals , Cell Line, Tumor , Drug Delivery Systems , Flow Cytometry , Mice , Microscopy, Fluorescence , Particle Size , Polylactic Acid-Polyglycolic Acid CopolymerABSTRACT
OBJECTIVES: The aim of this project was to develop a novel lipid-based formulation suitable for gene therapy. METHODS: Novel nanosize liposome (nanosome) formulations containing pDNA (plasmid DNA) were developed using high-pressure homogenization (HPH). The effect of lipid concentration was studied at two levels: 3 mm and 20 mm. The preformed nanosomes were incubated for 18-20 h with pDNA or pDNA/protamine sulfate (PS) complex. The physical properties of the pDNA nanosomes were compared by particle size distribution and zeta-potential measurements. Their biological properties were also compared by pDNA efficiency of encapsulation/complexation, integrity, nuclease digestion, transfection efficiency and cell cytotoxicity. KEY FINDINGS: pDNA nanosomes prepared with 20 mM lipid (nanosomes:pDNA:PS at a ratio of 8.6:1:2) had particle sizes of 170-422 nm (90% confidence). The zeta-potential of the formulation was 49.2 +/- 1.5 mV, and the pDNA encapsulation/complexation efficiency was approximately 98%. pDNA nanosomes prepared with 3 mM lipid (nanosomes:pDNA PS at a ratio of 2.09:1:2) had particle sizes of 140-263 nm (90% confidence). The zeta-potential of this formulation was 36.4 +/- 1.2 mV, and the pDNA encapsulation/complexation efficiency was approximately 100%. However, a comparison of the efficiency of transfection indicated that pDNA nanosomes prepared with low-concentration lipids (3 mM) showed significantly higher transfection efficiency compared with the pDNA nanosomes prepared with high-concentration lipids (20 mM), as well as those prepared with Fugene-6 (a commercially available transfection reagent). This particular formulation (pDNA nanosomes, 3 mM lipids) also showed significantly less cytotoxicity compared with the other pDNA nanosome formulations. CONCLUSIONS: To conclude, these results indicate that condensing pDNA with PS followed by subsequent complexation with low-concentration nanosomes generated from HPH can produce a pDNA nanosome formulation that will boost transfection efficiency, while minimizing cytotoxicity. This new technology appears to be an efficient tool for future commercial or large-scale manufacture of DNA delivery systems for gene therapy.
Subject(s)
Chemistry, Pharmaceutical/methods , DNA/chemistry , Genetic Therapy/methods , Genetic Vectors , Lipids/chemistry , Liposomes , Nanocapsules , Animals , Cell Line, Tumor , Gene Transfer Techniques , Mice , Plasmids , Pressure , Protamines/chemistry , TransfectionABSTRACT
The objective of this study was to prepare and evaluate a novel spray-dried tableting excipient using a mixture of chitosan and lactose. Three different grades of chitosan (low-, medium-, and high-molecular-weight) were used for this study. Propranolol hydrochloride was used as a model drug. A specific amount of chitosan (1, 1.9, and 2.5 g, respectively) was dissolved in 50 mL of an aqueous solution of citric acid (1%) and later mixed with 50 mL of an aqueous solution containing lactose (20, 19.1, and 18.5 g, respectively) and propanolol (2.2 g). The resultant solution was sprayed through a laboratory spray drier at 1.4 mL/min. The granules were evaluated for bulk density, tap density, Carr index, particle size distribution, surface morphology, thermal properties, and tableting properties. Bulk density of the granules decreased from 0.16 to 0.13 g/mL when the granules were prepared using medium- or high-molecular-weight chitosan compared with the low-molecular-weight chitosan. The relative proportion of chitosan also showed a significant effect on the bulk density. The granules prepared with 1 g of low-molecular-weight chitosan showed the minimum Carr index (11.1%) indicating the best flow properties among all five formulations. All three granules prepared with 1 g chitosan, irrespective of their molecular weight, showed excellent flow properties. Floating tablets prepared by direct compression of these granules with sodium bicarbonate showed 50% drug release between 30 and 35 min. In conclusion, the spray-dried granules prepared with chitosan and lactose showed excellent flow properties and were suitable for tableting.
