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New Drug Release Protocol Available

The NCL has just added a new protocol to our Assay Cascade Protocols page to measure drug release from nanomedicines. The protocol, PHA-2, is based off of the recent Journal of Controlled Release publication, Stable isotope method to measure drug release from nanomedicines. Since its publication in late 2015, this assay has gained a lot of attention and has been in high demand at the NCL, particularly in regards to bioequivalence analysis of follow-on/generic nanomedicines. The unique features of this assay include:

  • Can be done in biological matrix, either in vitro or using samples from an in vivo study
  • Can determine encapsulated, protein-bound, and free unbound drug concentrations
  • Utilizes a stable isotope of the drug, many of which are commercially available
  • No requirement for radioactivity (like NCL protocol PHA-1)

Drug release protocol image 1

The protocol uses a stable isotopically labeled version of the drug (D*) and a simple ultrafiltration technique. When spiked into plasma or other matrix, D* equilibrates with protein (Pro) and nanomedicine (NM) identical to the unlabeled, normoisotopic drug (D). Therefore, the ultrafiltrate fraction of the isotopically labeled drug represents a reliable measurement of the free drug fraction. The plasma protein bound, unencapsulated and encapsulated nanomedicine fractions can then be easily calculated.

new drug release protocol image 2

Have questions on the protocol? Let us know. Dr. Stephan Stern, developer of the technique, will be happy to address questions.