Solid Forms of Tenofovir Disoproxil Fumarate, Their Mutual Conversion, and Stabilization of Form I in Formulation

J Pharm Sci. 2016 Oct;105(10):3136-3142. doi: 10.1016/j.xphs.2016.07.002. Epub 2016 Aug 10.

Abstract

Tenofovir disoproxil fumarate (TDF, form I) is an orally delivered pharmaceutical salt used for the treatment of HIV and chronic hepatitis, which acts as an inhibitor of nucleotide reverse transcriptase. There are many solid forms of TDF described in the literature; 2 of them were identified in the drug products: form I and form A. It seems that during formulation, the active pharmaceutical ingredient undergoes partial to total conversion of TDF form I to TDF form A. The goals of this study were to investigate when and why did the conversion occur and whether the conversion could be avoided and how. The influence of pH and possible interaction with excipients were studied. The conditions enabling using wet granulation in technology while preventing the undesired conversion were found. The stabilization was achieved either by replacement of used disintegrants or by acid addition to the current composition of formulation.

Keywords: X-ray powder diffractometry; cocrystals; crystal polymorphism; drug-excipient interaction; formulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-HIV Agents / chemistry*
  • Anti-HIV Agents / metabolism*
  • Drug Compounding / methods*
  • Drug Stability
  • Excipients / chemistry
  • Excipients / metabolism
  • Hydrogen-Ion Concentration
  • Tenofovir / chemistry*
  • Tenofovir / metabolism*
  • X-Ray Diffraction / methods

Substances

  • Anti-HIV Agents
  • Excipients
  • Tenofovir