Determining DOXY Encapsulation Efficiency in PNPs

The EE% for DOXY in the prepared PNPs was determined by an indirect method [65 ]. The entrapped drug was separated from the un-entrapped by centrifugation [66 (link)] for 30 min at 14,000 rpm (17,979× g) using a Hettich centrifuge (Hettich, Mikro 22 R, Germany). The amount of the un-entrapped DOXY in the supernatant was estimated spectrophotometrically at 269 nm utilizing an ultraviolet spectrophotometer (Shimadzu, Japan). The experiment was done in triplicate and the EE% was calculated using the next equation [67 (link)]: $\mathrm{Encapsulation}\mathrm{efficiency}\%=\frac{\left(\mathrm{Total}\mathrm{DOXY}\right)-\left(\mathrm{Un}-\mathrm{entrapped}\mathrm{DOXY}\right)}{\mathrm{Total}\mathrm{DOXY}}\times 100$
Additionally, the loading capacity percentage which represents the percentage of the amount of drug (DOXY) in the prepared PNPs was determined. The loading capacity % was measured through the following equation [68 (link)]: $\mathrm{Loading}\mathrm{capacity}\%=\frac{\mathrm{Mass}\mathrm{ofentrappe}\mathrm{DOXY}}{\mathrm{Mass}\mathrm{of}\mathrm{prepared}\mathrm{PNPs}}\times 100$