Rapid Nanogram Scale Screening Method of Microarrays to Evaluate Drug-Polymer Blends Using High-Throughput Printing Technology.

A miniaturized, high-throughput assay was optimized to screen polymer-drug solid dispersions using a 2-D Inkjet printer. By simply printing nanoliter amounts of polymer and drug solutions onto an inert surface, drug/polymer microdots of tunable composition were produced in an easily addressable microarray format. The amount of material printed for each dried spot ranged from 25 ng to 650 ng. These arrays were used to assess the stability of drug/polymer dispersions with respect to recrystallization, using polarized light microscopy. One array with a panel of 6 drugs formulated at different ratios with a poly(vinylpyrrolidone-vinyl acetate) (PVPVA) copolymer was developed to estimate a possible bulk (gram-scale) approximation threshold from the final printed nanoamount of formulation. Another array was printed at a fixed final amount of material to establish a literature comparison of one drug formulated with different commercial polymers for validation. This new approach may offer significant efficiency in pharmaceutical formulation screening, with each experiment in the nanomicro-array format requiring from 3 up to 6 orders of magnitude lower amounts of sample than conventional screening methods.