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Combining orthogonal measurements to unveil diclofenac encapsulation into polymeric and lipid nanocarriers

Marques, S S; Cant, D J H; Minelli, C; Segundo, M A (2023) Combining orthogonal measurements to unveil diclofenac encapsulation into polymeric and lipid nanocarriers. Analytica Chimica Acta, 1262. 341234

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The quantification of the drug associated to nanoparticle carriers, often expressed in terms of encapsulation efficiency, is a regulatory requirement. The establishment of independent methods to evaluate this parameter provides a means for measurement validation, which is critical in providing confidence in the methods and enabling the robust characterization of nanomedicines. Chromatography is traditionally used to measure drug encapsulation into nanoparticles. Here, we describe an additional independent strategy based on analytical centrifugation. The encapsulation of diclofenac into nanocarriers was quantified based on the mass difference between placebo (i.e. unloaded) and loaded nanoparticles. This difference was estimated using particle densities measured by differential centrifugal sedimentation (DCS) and size and concentration values measured by particle tracking analysis (PTA). The proposed strategy was applied to two types of formulations, namely poly(lactic-co-glycolic acid) (PLGA) nanoparticles and nanostructured lipid carriers, which were analysed by DCS operated in sedimentation and flotation modes, respectively. The results were compared to those from high performance liquid chromatography measurements. Additionally, X-ray photoelectron spectroscopy analysis was used to elucidate the surface chemical composition of the placebo and loaded nanoparticles. The proposed approach enables the monitoring of batch-to-batch consistency and to quantify diclofenac association to PLGA nanoparticles from 0.7 ng to 5 ng of drug per 1 μg of PLGA, with good linear correlation between DCS and HPLC results (R2 = 0.975). Using the same approach, similar quantification in lipid nanocarriers was possible for a loading of diclofenac ≥ 1.1 ng per 1 μg of lipids, with results in agreement with the HPLC method (R2 = 0.971).

Item Type: Article
Keywords: Diclofenac Nanomedicine Nanoparticle characterization Encapsulation efficiency Regulatory requirements
Subjects: Nanoscience > Surface and Nanoanalysis
Divisions: Chemical & Biological Sciences
Identification number/DOI: 10.1016/j.aca.2023.341234
Last Modified: 04 Jul 2023 14:47
URI: http://eprintspublications.npl.co.uk/id/eprint/9776

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