Meticulous Doxorubicin Release from pH‐Responsive Nanoparticles Entrapped within an Injectable Thermoresponsive Depot

Abstract

The dual stimuli-controlled release of doxorubicin from gel-embedded nanoparticles is reported. Non-cytotoxic polymer nanoparticles are formed from poly(ethylene glycol)-b-poly(benzyl glutamate) that, uniquely,c ontain ac entral ester link. This connection renders the nanoparticles pH-responsive, enabling extensive doxorubicin release in acidic solutions (pH 6.5), but not in solutions of physiological pH (pH 7.4). Doxorubicin-loaded nanoparticles were found to be stable for at least 31 days and lethal against the three breast cancer cell lines tested.F urthermore, doxorubicin-loaded nanoparticles could be incorporated within at hermoresponsive poly(2-hydroxypropyl methacrylate) gel depot, whichf orms immediately upon injection of poly(2-hydroxypropyl methacrylate) in dimethyl sulfoxide solution into aqueous solution. The combination of the poly(2-hydroxypropyl methacrylate) gel and poly(ethyleneg lycol)-b-poly(benzylg lutamate) nanoparticles yields an injectable doxorubicin delivery system that facilities near-complete drug releasew hen maintained at elevated temperatures (37 8C) in acidic solution (pH 6.5). In contrast,n egligible payload release occurs when the material is stored at room temperature in nonacidic solution (pH 7.4). The system has great potential as av ehicle for the prolonged, site-specific release of chemotherapeutics.

Controlled Sr(ii) ion release from in situ crosslinking electroactive hydrogels with potential for the treatment of infections

“…The size of the nanoparticles was also conrmed using scanning electron microscopy and it can be seen that particle size is mostly around 110 nm and the diameters of aggregates are around 250 nm which is still injectable via needles of a variety of gauge sizes used in surgical procedures. [67][68][69][70][71][72][73][74] Scanning electron microscopy (SEM)…”