However, it can cause side effects such as cardiotoxicity

and drug resistance. Also, it is difficult to administer intravenously because of its low solubility in aqueous media. Nanomaterial-based drug delivery systems have received attention in overcoming Alectinib in vitro this drawback. These systems can be made from a variety of organic and inorganic materials including non-degradable and biodegradable polymers, and inorganic nanocrystals. Polymeric micelles based on amphiphilic block copolymers have the advantages of high biocompatibility and drug-loading capacity with low toxicity because they can self-assemble into polymeric micelles in aqueous media [8, 15–17]. They accumulate in tumors through an enhanced permeation and retention (EPR) effect compared to single small molecules, leading to preferential spatio-distribution in the tumor. However, the drug release behavior of polymeric micelles is difficult to control; they freely release the drug before reaching tumors, which could give rise to unwanted side effects and low

therapeutic efficacy [4, 8]. Well-designed drug delivery systems need to be developed to enable cancer chemotherapy that fundamentally enhances therapeutic efficacy by minimizing drug release in undesirable sites. With these systems, a precise drug concentration can be delivered to tumors to reduce side effects. Drug delivery systems can be designed to release drugs triggered by environmental parameters such as pH, enzymes, and temperature [16, 18–29]. Y 27632 The pH-sensitive systems are of special interest because tumors and intracellular endosomal/lysomal compartments exhibit abnormally high local acidities compared to healthy tissues with a normal physiological pH of 7.4 [9, 21, 25, 28–43]. In this study, chitosan-based intelligent theragnosis nanocomposites that enable pH-sensitive drug release with magnetic resonance (MR)-guided images were developed (Figure 1). This nanocomposite was based on N-naphthyl-O-dimethymaleoyl

chitosan (N-nap-O-MalCS), a newly synthesized, pH-sensitive amphiphilic copolymer modified by maleoyl groups on a chitosan backbone. Chitosan is non-toxic, biodegradable, and non-immunogenic [44–72]. It is a linear polysaccharide Montelukast Sodium consisting of N-acetyl-glucosamine (acetylated) and glucosamine (deacetylated) repeating units, and its abundant reactive groups facilitate chemical modification of functional groups. Hydrophobic magnetic nanocrystals were loaded as imaging agents in this system, leading to the formulation of theragnosis nanocomposites capable of delivery therapy concomitant with monitoring. This nanocomposite will allow effective cancer therapy because it can provide patient-specific drug administration strategies that consider drug-release patterns and biodistribution. Figure 1 Schematic illustration of N Chitosan-DMNPs enabling pH-sensitive drug release and MR monitoring for cancer therapy. Methods Materials Chitosan with an average molecular weight (mol. wt.