The interaction between cationic amino groups on chitosan and anionic moieties such as sialic and sulfonic acids on the mucus layer is responsible for its mucoadhesiveness [16]. In addition, chitosan enhances epithelial permeability through the opening of tight junctions between epithelial cells [17]. Recently, it was reported that the covalent attachment of thiol groups to polymers greatly increases their mucoadhesiveness and permeation properties without affecting biodegradability [16, 18]. Thiolated

chitosan-modified nanoparticles are expected to be appropriate carriers for oral absorption of drugs [19–21]. Thiolated chitosan has many advantages as a carrier in nanoparticulate drug delivery systems. It is nontoxic, biocompatible, and biodegradable and has been proven to control the release of drugs, proteins, and peptides. It is soluble in aqueous media, avoids the use of organic solvents, and does not require further Selleckchem PD173074 purification of nanoparticles [22]. Thus, thiolated chitosan was used in the present study to be absorbed on the nanoparticle surface by electrostatic forces of attraction between positive and negative charges. In this research, PLA-PCL was used to maintain the desirable mechanical strength of the polymer. Vitamin E d-α-tocopheryl polyethylene glycol 1000 succinate (Vitamin E TPGS, or simply TPGS) is

Selleckchem Alvocidib a water-soluble derivative of naturally sourced vitamin E, which is formed by esterification of vitamin E succinate

with polyethylene glycol 1000. Previous studies revealed that TPGS was able to improve drug permeability across biological membranes pheromone by inhibition of P-gp pumps and, thus, increase the drug absorption capability and Selleckchem BYL719 decrease P-gp-mediated MDR in cancer cells [23–25]. In addition, TPGS was able to effectively inhibit the growth of human lung cancer cells in cell culture and in animal models [26]. The superior antitumor activity of TPGS is mainly due to its increasing ability to induce apoptosis in tumor cells [26–28]. A few studies have shown synergistic effects of combinations of TPGS with other antitumor drugs [27]. Furthermore, it has been found that TPGS-emulsified nanoparticles had higher encapsulation efficacy and cellular uptake, longer half-life, and higher therapeutic efficiency of the formulated drug than those emulsified by poly(vinyl alcohol), a commonly used emulsifier in nanoparticle formulation process [24]. Thus, we were inspired to fabricate a novel thiolated chitosan-modified PLA-PCL-TPGS nanoparticle as oral anticancer drug carrier for lung cancer chemotherapy. The chemical structure of PLA-PCL-TPGS random copolymer is shown in Figure 1[24]. Figure 1 Chemical structure and 1 H-NMR spectra of PLA-PCL-TPGS copolymer. (A) Chemical structure of PLA-PCL-TPGS copolymer; (B) typical 1H-NMR spectra of PLA-PCL-TPGS copolymer.