Polymeric nanoparticles (NPs) have promising applications in agriculture for the controlled release of agrochemicals. This study specifically investigates nanoparticles for antibiotic delivery, where enhanced efficiency of the drug delivery can help to mitigate antibiotic resistance concerns in the environment. Because the controlled release behavior and transport behavior are critical for nanoparticles used in plant or animal applications, characterization of the drug release profile and size distribution is essential. This study demonstrates the application of asymmetric flow field-flow fractionation (AF4) with a series of online detectors [UV-vis, fluorescence, and dynamic light scattering (DLS)] to identify how the material properties of the NPs (glass transition temperature, particle size) and release environment (temperature, matrix components) can affect the release rate of a fluorescent antibiotic ingredient. This method enables us to directly monitor the drug loading and release from the NPs at different temperatures and across the size distribution of the NPs. In contrast to dialysis (a common method involving indirect measurement of release and transport across a dialysis membrane), the AF4 method was able to capture the thermosensitive release behavior of the particles and yield the “true” release rate by selectively probing the drug entrapped in the NPs. Additionally, coupling the release profiles with the high-resolution size data obtained by AF4-DLS permitted the analysis of size-dependent release rates across the entire continuous NP size distribution to study fundamental structure-function relationships (i.e., the role of NP size on the release rate). Finally, the AF4 method enables separation of complex mixtures of polymeric NPs in biological milieu (e.g., gastrointestinal media containing digestive proteins) and hence changes in drug distribution between the different media components (NPs, proteins). In the last part of study, we will discuss the feasibility of utilizing the AF4 methods to probe the drug release and distribution when applying polymeric NPs in these more complex media.

Investigation of the effect of material and matrix properties on active ingredient release from polymeric nanoparticles by asymmetric flow field-flow fractionation (AF4)

ACS Spring Meeting 2021

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