Three-Step Synthesis of a Redox-Responsive Blend of PEG–block–PLA and PLA and Application to the Nanoencapsulation of Retinol

Abstract

Smart polymeric nanocarriers have been developed to deliver therapeutic agents directly to the intended site of action, with superior efficacy. Herein, a mixture of poly(lactide) (PLA) and redox-responsive poly(ethylene glycol)–block–poly(lactide) (PEG–block–PLA) containing a disulfide bond was synthesized in three steps. The nanoprecipitation method was used to prepare an aqueous suspension of polymeric nanocarriers with a hydrodynamic diameter close to 100 nm. Retinol, an anti-aging agent very common in cosmetics, was loaded into these smart nanocarriers as a model to measure their capacity to encapsulate and to protect a lipophilic active molecule. Retinol was encapsulated with a high efficiency with final loading close to 10% w/w. The stimuli-responsive behavior of these nanocarriers was demonstrated in vitro, in the presence of l-Glutathione, susceptible to break of disulfide bond. The toxicity was low on human keratinocytes in vitro and was mainly related to the active molecule. Those results show that it is not necessary to use 100% of smart copolymer in a nanosystem to obtain a triggered release of their content.

Polymer-Based Smart Drug Delivery Systems for Skin Application and Demonstration of Stimuli-Responsiveness

“…This is not discussed in the literature yet but has an important impact on the industrial feasibility of the systems. Our recent results indicated that the SDDS made of only 33% of the redox responsive mPEG-SS-PLA polymers were active in vitro [ 124 ]. Thus, the use of a mixture of stimuli-responsive and neutral polymers could be a way to control the SDDS cost.…”

“…The strategy of disulfide bonds incorporation was used by our group [ 124 ] in order to develop redox-responsive nanoparticles for topical applications. Briefly, a mixture of poly(lactide) (PLA) and redox-responsive poly(ethylene glycol)-block-poly(lactide) (PEG-block-PLA) containing a disulfide bond was synthesized in three steps.…”

Smart PEG-Block-PLA/PLA Nanosystems: Impact of the Characteristics of the Polymer Blend on the Redox Responsiveness

“…Lately, a method to synthesize a redox-responsive blend of mPEG-b-PLA/PLA polymers was developed in our laboratory [ 19 ]. Briefly, a blend of redox-responsive mPEG-SS-PLA copolymer and a non-responsive PLA polymer (ratio 1:2) was synthesized in three steps and used for retinol encapsulation.…”

Triblock Copolymer Compatibilizers for Enhancing the Mechanical Properties of a Renewable Bio-Polymer

“…Thus, it is prominent in the emerging bio-plastics market [3,4]. However, PLA is insufficient for most commercial applications, especially in engineering fields such as the automotive industry, because of its innate shortcomings (such as brittleness, slow rate of crystallization, and hydrolysis [5,6]). The mechanical performance of polymers depends on several parameters such as the enhance phase, interface compatibility and the preparation technology [7][8][9].…”