Nanospheres and nanocapsules of amphiphilic copolymers constituted by methoxypolyethylene glycol cyanoacrylate and hexadecyl cyanoacrylate units

Abstract

Nanospheres and nanocapsules of an amphiphilic copolymer having methylated polyethylene glycol and hexadecyl lateral groups were prepared by the solvent displacement method and using confined impinging jet mixers. Degradation, thermal properties and crystalline structure were investigated. Interestingly, pegylated chains hydrolyzed through ester bond cleavage, whereas the more hydrophobic hexadecyl ester groups were resistant to degradation in aqueous media. The copolymer crystallized from the melt, giving rise to spherulites with a negative birefringence and domains corresponding to crystallization of the different lateral groups. Size distribution and morphology of nanoparticles were mainly evaluated by electron microscopy. Nanocapsules were characterized by a stable membrane with a thickness close to 5 nm that allowed efficient encapsulation of a triglyceride oil. Triclosan was selected as an example of a hydrophobic drug to be loaded in both nanospheres and nanocapsules. The release behavior of these dosage forms was clearly different. Thus, the Burst effect was practically suppressed when using nanocapsules; in addition, these showed a sustained, controlled release over a greater time period. Antimicrobial activity of triclosan loaded nanospheres and nanocapsules was evaluated using Gram-negative and Gram-positive bacteria. The former were highly sensitive to the released triclosan whereas the latter strongly depended on the number of particles in the culture medium

Dynamic Light Scattering and X-ray Photoelectron Spectroscopy Characterization of PEGylated Polymer Nanocarriers: Internal Structure and Surface Properties

“…Eventually for an MR of 0.76, the change in the detected intensities did not appear even at 90°, pointing to a wall thickness of NC of >8.4 nm. All of these values are summarized in Table 1 and compared with wall thicknesses estimated from transmission electron microscopy (TEM) observations (comparable to those conducted in another study 26 ) reported in Figure 7.…”

Erlotinib entrapped in cholesterol-depleting cyclodextrin nanoparticles shows improved antitumoral efficacy in 3D spheroid tumors of the lung and the liver

“…When the luminous intensity of fluorescent dye is examined microscopically, it can be said that the penetration of nanocapsule formulations for all CD derivatives is higher than the nanosphere analogues. One of the reasons for this result can be attributed to the nanocapsules oil core [85] that results in a higher liquid content for the delivery system and decreases stiffness of the polymer membrane surrounding the core. We believe that this may have facilitated the intercellular passage of the nanocapsules within the 3D tumor model that is a dense and complicated structure.…”

Preparation and comparison of spray dried and electrospun bioresorbable drug delivery systems

“…Poly(lactic acid) (PLA) and poly(lactide-co-glycolide) (PLGA) are such bioresorbable and thermoplastic water-insoluble polymers (approved by all the relevant authorities for use in human subjects). These biocompatible polymers have been employed as suture materials [8], inter-body cages [14], scaffolds for tissue engineering [15], and biodegradable drug delivery systems [16] with sustained drug release [17]. Both PLA and PLGA matrices are frequently applied to achieve sustained drug release, but a so-called ''burst effect'' is experienced in many cases [18,19].…”