Functional Polymers for Drug Delivery Systems in Nanomedicines

Abstract

− Polymeric based nanomedicines have been developed for diagnosing, treating, and preventing diseases in human body. The nanosized drug delivery systems having various structures such as micelles, nanogels, drug-conjugates, and polyplex were investigated for a great goal in pharmaceutics: increasing therapeutic efficacy for diseases and decreasing drug toxicity for normal tissues. The functional polymers used for constituting these drug delivery systems should have several favorable properties such as stimuli-responsibility and biodegrdability for controlled drug release, and solublization capacity for programmed drug encapsulation. This review discusses recent developments and trends of functional polymers (e.g., pH-sensitive polymers, biodegradable polymers, and cationic polymers) used for nanosized drug carriers.

A feasibility study of a pH sensitive nanomedicine using doxorubicin loaded poly(aspartic acid-graft-imidazole)-block-poly(ethylene glycol) micelles

“…[16][17][18][19] In particular, pH-sensitive micelles formulated as nanomedicines have attracted interest in chemotherapy due to their potential of an improved stability, reduced toxicity, passive targeting by enhanced permeability and retention (EPR) effects, and the controlled release of anticancer agents by tumor extracellular pH (pH ex ¼ $6.5 to 7.2) or endosomal pH (pH en # 6.5). 18,[20][21][22][23][24][25][26][27][28] The micelles self-assembled from block copolymers are generally composed of a polyelectrolyte block and a hydrophilic poly(ethylene glycol) (PEG) block and have demonstrated a pH-dependent behavior owing to the protonation or deprotonation of the polyelectrolyte blocks. For example, poly(histidine)-PEG-(poly(His)-PEG) can form a robust micelle at pHs exceeding 7.4 due to increased hydrophobicity of poly(His) blocks by deprotonation.…”

An On-Demand pH-Sensitive Nanocluster for Cancer Treatment by Combining Photothermal Therapy and Chemotherapy

“…Polymeric biomaterials have been utilized as advanced drug carriers [ 23 , 24 , 25 , 26 , 27 ], because their properties can be controlled by small changes in environmental conditions [ 24 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ], to improve therapeutic efficacy and minimize undesirable side effects [ 36 , 37 , 38 , 39 , 40 , 41 ]. Among the various polymeric biomaterials, pH-sensitive polymers have been developed as promising drug carriers for pH-dependent drug release in distinctive tumor microenvironments, such as tumor extracellular pH (pH ex , ranging from 6.5 to 7.2) and endosomal pH (pH en ≤ 6.5) [ 32 , 42 , 43 , 44 , 45 , 46 ]. In particular, nanocarriers based on pH-sensitive biomaterials have shown outstanding in vitro and in vivo tumor inhibition by higher drug release.…”

A novel 1,2,3-benzotriazolium based ionic liquid monomer for preparation of MMT/poly ionic liquid (PIL) pH-sensitive positive charge nanocomposites

“…Based on their chemical structure, functional polymers can be divided into three categories: pH-sensitive, biocompatible, and cationic polymers. 2 The pH gradient is one of the first stimuli in the body that attracted considerable attention, and it has been predominantly studied in recent biomedical researches. The pH-sensitive polymers deliver drugs into cells by the environmental pH changes.…”