Nanoparticles activate increased drug performance when administered intravenously, orally or through ocular and transcutaneous delivery routes.
The recently formulated chitosan-based polymeric micelle, Quaternary Ammonium Palmitoyl Glycol Chitosan (GCPQ) can effectively encapsulate drugs, thereby increasing oral absorption as well as intravenous activity by up to one order of magnitude. However, the interaction of GCPQ micelles with organs at the cellular level and its related mechanism is yet to be comprehended.
Multimodal nonlinear optical microscopy was employed by Natalie Laura Garrett and the research team from the University of Exeter for investigating these mechanisms by orally delivering deuterated GCPQ to mice.
Coherent anti-Stokes Raman scattering (CARS) microscopy has been integrated to second harmonic generation (SHG) and two photon fluorescence (TPF) microscopy to develop a multi-modal label-free method. CARS microscopy is more beneficial than conventional imaging. It provides up to hundreds of micron depth penetration within the biological tissue, label-free chemically specific contrast, intrinsic optical sectioning and high spatial resolution. When incorporated with CARS microscopy, TPF and SHG present a clear 3-D imagery of nanoparticles accentuating sub-cellular precision against a complex biological scenario.
The multi-modal method can image three vital target organs for oral drug delivery such as the intestine, the liver, and the gall bladder. This unique demonstration represents that orally administered chitosan nanoparticles undergo a recirculation pathway. It emerges from gastrointestinal tract through enterocytes in the villi, followed by passage into the blood stream. Following transport into hepatocytes and hepatocellular spaces of the liver, it reaches the gall bladder, prior to being re-released into the gut along with bile. Such recirculation may enhance drug absorption.