Insights on Ultrafiltration-Based Separation for the Purification and Quantification of Methotrexate in Nanocarriers

Abstract

The evaluation of encapsulation efficiency is a regulatory requirement for the characterization of drug delivery systems. However, the difficulties in efficiently separating nanomedicines from the free drug may compromise the achievement of accurate determinations. Herein, ultrafiltration was exploited as a separative strategy towards the evaluation of methotrexate (MTX) encapsulation efficiency in nanostructured lipid carriers and polymeric nanoparticles. The effect of experimental conditions such as pH and the amount of surfactant present in the ultrafiltration media was addressed aiming at the selection of suitable conditions for the effective purification of nanocarriers. MTX-loaded nanoparticles were then submitted to ultrafiltration and the portions remaining in the upper compartment of the filtering device and in the ultrafiltrate were collected and analyzed by HPLC-UV using a reversed-phase (C18) monolithic column. A short centrifugation time (5 min) was suitable for establishing the amount of encapsulated MTX in nanostructured lipid carriers, based on the assumption that the free MTX concentration was the same in the upper compartment and in the ultrafiltrate. The defined conditions allowed the efficient separation of nanocarriers from the free drug, with recoveries of >85% even when nanoparticles were present in cell culture media and in pig skin surrogate from permeation assays.

Novel Green Biosynthesis of 5-Fluorouracil Chromium Nanoparticles Using Harpullia pendula Extract for Treatment of Colorectal Cancer

“…CrNPs were added to previously prepared 200 mL aqueous solutions of different concentrations of 5-Fuin volumetric flasks (250 mL). They were then placed in a thermostatically controlled water bath shaker that was operated at different temperature degrees and 500 rpm for 24 h. Finally, the prepared 5-FuCrNPs were separated from the solution by ultrafiltration using a 50 kDa pore size filter [ 37 ].…”

A Novel Chitosan Nanosponge as a Vehicle for Transepidermal Drug Delivery

“…Compared to physical separation methodology, ultrafiltration does not need extensive time and dilution. To improve accuracy using the methodology, the minimized range molecular weight cutoff device was used and interaction between nanoparticle and filter materials reduced [ 39 , 40 ]. The characteristics of CNSs after drug loading were similar to those of unloaded CNSs and showed a similar increasing tendency of the size and zeta potential with increasing chitosan ratios ( Figure 3 B).…”

Amlexanox-loaded nanoliposomes showing enhanced anti-inflammatory activity in cultured macrophages: A potential formulation for treatment of oral aphthous stomatitis

“…Determination of drug entrapment efficiency. Entrapment efficiency of AMX was determined after adapting the previously reported separation method [18][19][20][21]. The drug entrapment efficiency in sonicated and non-sonicated preparations (three batches each) were determined after separation of the unentrapped free drug from drug loaded liposomes by ultra-filtration using 0.5 mL Amicon® filters (3K Da cut-off molecular weight, (MWCO), Fisher Scientific, UK).…”