In vivo pharmacokinetics, biodistribution and antitumor effect of amphiphilic poly(L-amino acids) micelles loaded with a novel all-trans retinoic acid derivative

Poly(phenylalanine) and poly(3,4-dihydroxy-L-phenylalanine): Promising biomedical materials for building stimuli-responsive nanocarriers

Cancer is a serious threat to human health because of its high annual mortality rate. It has attracted significant attention in healthcare, and identifying effective strategies for the treatment and relief of cancer pain requires urgency. Drug delivery systems (DDSs) offer the advantages of excellent efficacy, low cost, and low toxicity for targeting drugs to tumor sites. In recent decades, copolymer carriers based on poly(phenylalanine) (PPhe) and poly(3,4-dihydroxy-L-phenylalanine) (PDopa) have been extensively investigated owing to their good biocompatibility, biodegradability, and controllable stimulus responsiveness, which have resulted in DDSs with loading and targeted delivery capabilities. In this review, we introduce the synthesis of PPhe and PDopa, highlighting the latest proposed synthetic routes and comparing the differences in drug delivery between PPhe and PDopa. Subsequently, we summarize the various applications of PPhe and PDopa in nanoscale-targeted DDSs, providing a comprehensive analysis of the drug release behavior based on different stimulus-responsive carriers using these two materials. In the end, we discuss the challenges and prospects of polypeptide-based DDSs in the field of cancer therapy, aiming to promote their further development to meet the growing demands for treatment.

Gypenoside XLIX loaded nanoparticles targeting therapy for renal fibrosis and its mechanism

Renal fibrosis is the main pathological feature of the occurrence and development of chronic nephropathy. At present, there is no effective treatment, except for renal transplantation and dialysis. Previous studies have shown that nano-preparations can be used as a therapeutic tool to target organs. In this study, we studied the therapeutic effect and mechanism of Chinese medicine monomer Gypenoside (Gyp) XLIX on renal fibrosis and explored the targeting and therapeutic effects of polylactic acid-co-glycoside (PLGA)-Gyp XLIX nanoparticles in unilateral ureteral occlusion (UUO) kidney. Gyp XLIX and PLGA-Gyp XLIX nanoparticles were used to treat UUO mice and Human renal tubular epithelial (HK2) cells stimulated by transforming growth factor-β (TGF-β). Histopathological and molecular biological techniques were used to detect the expression of type I collagen and alpha-smooth muscle actin (α-SMA). To investigate the in vivo targeting of PLGA nanoparticles, they were loaded with 1,1-dioctadecyl-3,3,3,3-tetramethylindotricarbocyanine iodide and injected into UUO mice. We evaluated the effect of Gyp XLIX nanoparticles on TGF-β/Smad3 pathway, a central driver for renal fibrosis in Smad-deficient HK2 cells. Fluorescence imaging showed that the PLGA nanoparticles around 120 nm could be targeted to the UUO kidney. Compared with Gyp XLIX, PLGA-Gyp XLIX nanoparticles could effectively inhibit renal fibrosis and reduce collagen deposition and reduce renal tubular necrosis. Gyp XLIX decreased the phosphorylation of Smad3, but could not further reduce the levels of type I collagen and α-SMA in Smad-deficient cells. This study opens a promising way for targeted drug treatment of renal fibrosis.

Puerarin-loaded PEG-PE micelles with enhanced anti-apoptotic effect and better pharmacokinetic profile

Puerarin (PUE) is the most abundant isoflavonoid in kudzu root. It is widely used as a therapeutic agent for the treatment of cardiovascular diseases. However, the short elimination half-life, poor-bioavailability, and acute intravascular hemolysis of PUE are the main obstacles to its widespread clinical applications. Whereas PEG-PE micelles possess the ability to release medicine slowly, enhance the cellular uptake of drugs and improve their biocompatibility. Therefore, it was aim to fabricate puerarin-loaded PEG-PE (PUE@PEG-PE) micelles to improve the pharmaceutical properties of drugs. It can be observed from the TEM images that PUE@PEG-PE micelles appeared obvious core-shell structure and remained well-dispersed without aggregation and adhesion. PUE was successfully embedded in the core of PEG-PE micelles, which was confirmed by FT-IR and ¹H NMR spectra. In vitro studies showed that PUE@PEG-PE micelles exhibited a sustained release behavior in pH 7.4 PBS buffer and decreased hemolysis rate of PUE. Compared with PUE, PUE@PEG-PE micelles showed a 3.2-fold increase in the half-life of PUE and a 1.58-fold increase in bioavailability. In addition, the PUE@PEG-PE micelles exerted enhanced protective effect against isoprenaline-induced H9c2 cells apoptosis compared with PUE, as evident by decreased percentage of Hoechst-positive cells, Caspase 3 activity, Bax expression, and increased Bcl-2 expression. Notably, the PEG-PE micelles exhibited favorable cellular uptake efficiency on H9c2 cells, and this may account for their enhanced anti-apoptotic effect of the incorporated drug. Altogether, the PUE@PEG-PE micelles were not only able to control the drug release but also offered promise to enhance the pharmacokinetic and pharmacodynamic potential of PUE.

Disulfide cross-linked cholic-acid modified PEG–poly(amino acid) block copolymer micelles for controlled drug delivery of doxorubicin

Reduction responsive biodegradable core-cross-linked micelles are developed form lipoic acid and cholic acid decorated poly(ethylene glycol)-b-poly(l-glutamic acid) block copolymers and investigated for intracellular doxorubicin release.