---
title: Probing the Source of an Unstable Impurity and Controlling Its Formation at Release - Adare Pharma Solutions
description: Explore how researchers addressed impurity issues in the development of the extended-release anti-neoplastic agent APT-76 for a Phase 1 clinical trial.
---

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# [Probing the Source of an Unstable Impurity and Controlling Its Formation at Release - Adare Pharma Solutions](https://info.adarepharmasolutions.com/resources/probing-the-source-of-an-unstable-impurity-and-controlling-its-formation-at-release)

 Written by [Adare Pharma Solutions](https://info.adarepharmasolutions.com/resources/author/adare-pharma-solutions) | Feb 27, 2026 5:00:00 AM

#### Authors: Geraldine Su, Ken Strassberger, Craig Kramer, Xinqun Huang, and Mike Markham

APT-76 is an anti-neoplastic agent and currently being developed as an extended-release formulation (enteric coating) for an ongoing early Phase 1 clinical trial. The finished drug product is a capsule filled with mini tablets. Two major issues related to impurities were encountered during the formulation and analytical stages:

1. Significant growth of a known impurity (DPI, Dephosphorylated Impurity, MH+ = 286) was observed. Use of pure alcoholic solvent, sonication, and temperature for extraction facilitates the formation of DPI.

2. Formation of an unknown impurity (Unk-3), which was above the qualification threshold (0.34% at release).

[View full post](https://info.adarepharmasolutions.com/resources/probing-the-source-of-an-unstable-impurity-and-controlling-its-formation-at-release)

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