A poly (amino acid)-based amphiphilic copolymer was utilized to fabricate a better micellar drug delivery system (DDS) with improved compatibility and sustained release of doxorubicin (DOX). First, poly (ethylene glycol) monomethyl ether (mPEG) and DOX were conjugated onto polyasparihyazide (PAHy), prepared by hydrazinolysis of the poly (succinimide) (PSI), to afford an amphiphilic polymer [PEG-hyd-P (AHy-hyd-DOX)] with acid-liable hydrazone bonds. The DOX, chemically conjugated to the PAHy, was designed to supply hydrophobic segments. PEGs were also grafted to the polymer via hydrazone bonds to supply hydrophiphilic segments and prolong its lifetime in blood circulation. Free DOX molecules could be entrapped into the nanoparticles fabricated by such an amphiphilic polymer (PEG-hyd-P (AHy-hyd-DOX)), via hydrophobic interaction and π–π stacking between the conjugated and free DOX molecules to obtain a pH responsive drug delivery system with high DOX loaded. The drug loading capacity, drug release behavior, and morphology of the micelles were investigated. The biological activity of micelles was evaluated in vitro. The drug loading capacity was intensively augmented by adjusting the feed ratio, and the maximum loading capacity was as high as 38%. Besides, the DOX-loaded system exhibited pH-dependent drug release profiles in vitro. The cumulative release of DOX was much faster at pH 5.0 than that at pH 7.4. The DOX-loaded system kept highly antitumor activity for a long time, compared with free DOX. This easy-prepared DDS, with features of biocompatibility, biodegradability, high drug loading capacity and pH-responsiveness, was a promising controlled release delivery system for DOX.
Available online 6 June 2013
Source:Current Opinion in Chemical Biology Author(s): Rita L Strack , Samie R Jaffrey Tools to study the abundance, distribution, and flux of intracellular molecules are crucial for understanding cellular signaling and physiology. Altho ... more
Available online 3 June 2013
Source:Current Opinion in Chemical Biology Author(s): Yuichiro Hori , Kazuya Kikuchi Protein labeling by using a protein tag and its specific fluorescent probe is increasingly becoming a useful technique for the real-time imaging of pro ... more
The average 5-year survival for colorectal cancer (CRC) is less than 10% if metastasis occurs, but can reach 90% if detected early. A new non-invasive test has been developed that measures methylation of the SDC2 gene in tissues and blood sera. This test detected 87% of all stages of colore ... more
Regular marijuana use is associated with favorable indices related to diabetic control, say investigators. They found that current marijuana users had significantly lower fasting insulin and were less likely to be insulin resistant, even after excluding patients with a diagnosis of diabetes ... more
Most children who suffer from sports-related concussions recover within a few days. However, in a small number of children, symptoms can last for a month or more. Although there have been numerous theories as to what might predict a longer recovery time, there is no definitive answer as to ... more