Amicon centrifugal filters

The yield of the HSA-NPs was measured by UV-spectrophotometry. A standard curve of HSA dissolved in a solution of phosphate buffered saline (PBS) was used as a reference. The absorbance values for HSA were measured at 280 nm. The following equation was used for the calculation of the yield.
The HSA–HU-NPs were spin-concentrated using Amicon centrifugal filters (Cedarlane, Burlington, ON, Canada) with a molecular weight cut off (MWCO) of 10,000 Da to calculate the encapsulation efficiency of hydroxyurea in HSA-NPs. This allowed the non-encapsulated hydroxyurea drug to be eluted into the collection tube. The concentration of non-encapsulated hydroxyurea was determined by the high performance liquid chromatography (HPLC) method (Shimadzu LC-20 Prominence).

The in vitro drug release was measured by the UV-visible spectrophotometric method as published previously [4 ,26 (link),27 (link)]. In brief, PTX-HSA-NPs were spin concentrated using Amicon centrifugal filters (Cedarlane, Burlington, ON, Canada) with MWCO 10,000 Da. The nanoparticles were re-suspended in 5 mL PBS and placed in a shaker at 37 °C at 120 rpm. At pre-determined time intervals (0, 1, 2, 9, 12, 18, 24 and 48 h), 0.5 mL of the PTX-HSA-NPs solution was withdrawn starting from 0 h for the absorbance measurement at 230 nm and re-substituted with 0.5 mL of fresh PBS. From the absorbance measurements, the cumulative amount of PTX released into the solution at the different time intervals was determined. This study was performed in triplicates.

The yield of the HSA-NPs was measured by the UV-spectrophotometric method. A standard curve of HSA dissolved in a solution of phosphate buffered saline (PBS), containing 0.02% v/v Tween 20% v/v and 10% v/v acetonitrile, was used as a reference. The absorbance values for HSA were measured at 280 nm. For the calculation of the yield, the following equation was used.

To calculate the encapsulation efficiency of paclitaxel in HSA-NPs, the PTX-HSA-NPs were spin concentrated using Amicon centrifugal filters (Cedarlane, Burlington, ON, Canada) with a molecular weight cut off (MWCO) of 10,000 Da. This allowed the non-encapsulated paclitaxel drug to be eluted out in the collection tube. The concentration of non-encapsulated PTX was determined by the UV-spectrophotometric method. A standard curve of PTX in a mixture containing MeOH/PBS (30:70) and 1% v/v sodium dodecyl sulfate (SDS) was used as a reference [46 (link)]. The absorbance values were measured at 230 nm. The encapsulated paclitaxel in the PTX-HSA-NPs was calculated using the following equation.