Using Nonlinear Optical Methods to Investigate Pharmaceuticals and Dynamic Systems

Janny Dinh, Purdue University

Abstract

Light microscopy, including nonlinear optical (NLO) microscopy, has been an enormously powerful tool in discovering the nature of and underlying mechanisms driving so many of the phenomena observed in the world. Second harmonic generation (SHG) imaging, in particular, is a valuable technique for the in-depth study of systems that are inaccessible by other optical methods without altering its natural state. The dissolution behavior of pharmaceutical compounds, for example, is not easily investigated using other methods if the samples are prepared in media that accurately typify the true biological environment of the consumed drug. With second-order nonlinear optical imaging of chiral crystals (SONICC), however, amorphous solid dispersions (ASDs) of active pharmaceutical ingredients (APIs) can be probed within turbid, biorelevant media. The crystallization kinetics and phase transformation behavior of ASDs of ezetimibe were found to vary depending not only on the polymer it was bound with, but also on the solution in which it was initially dissolved. Given its ability to penetrate biological tissues, NLO imaging is also an effective method for the in vivo study of biological materials, including the human brain. Capturing the rapid firing of neurons in order to volume map the brain and further enhance our understanding of nature’s most complex organ requires a technique capable of high speed and multifocal imaging. An instrument that divides an incident beam and temporally delays the resulting beams in addition to separating them in space such that each beam accesses a different focal plane in the sample was developed and described herein.

Degree

M.S.

Advisors

Simpson, Purdue University.

Subject Area

Analytical chemistry

COinS