Click Biotinylation of PLGA Template for Biotin Receptor Oriented Delivery of Doxorubicin Hydrochloride in 4T1 Cell-Induced Breast Cancer

PLGA was functionalized with PEG and biotin using click chemistry to generate a biotin receptor targeted copolymer (biotinylated–PEG-PLGA) which in turn was used to fabricate ultrafine nanoparticles (BPNP) of doxorubicin hydrochloride (DOX) for effective delivery in 4T1 cell induced breast cancer. However, adequate entrapment of a hydrophilic bioactive like DOX in a hydrophobic polymer system made of PLGA is not usually possible. We therefore modified a conventional W/O/W emulsion method by utilizing NH₄Cl in the external phase to constrain DOX in dissolved polymer phase by suppressing DOX’s inherent aqueous solubility as per common ion effect. This resulted in over 8-fold enhancement in entrapment efficiency of DOX inside BPNP, which otherwise is highly susceptible to leakage due to its relatively high aqueous solubility. TEM and DLS established BPNP to be sized below 100 nm, storage stability studies showed that BPNP were stable for one month at 4 °C, and <i>in vitro</i> release suggested significant control in drug release. Extensive <i>in vitro</i> and <i>in vivo</i> studies were conducted to propound anticancer and antiproliferative activity of BPNP. Plasma and tissue distribution study supplemented by pertinent <i>in vivo</i> fluorescence imaging mapped the exact fate of DOX contained inside BPNP once it was administered intravenously. A comparative safety profile via acute toxicity studies in mice was also generated to out rightly establish usefulness of BPNP. Results suggest that BPNP substantially enhance anticancer activity of DOX while simultaneously mitigating its toxic potential due to altered spatial and temporal presentation of drug and consequently deserve further allometric iteration