Matrix modifications modulate ophthalmic drug delivery from photo-cross-linked poly(propylene fumarate)-based networks

J Biomater Sci Polym Ed. 2009;20(1):49-69. doi: 10.1163/156856208X393491.

Abstract

In this work, different modifications of photo-cross-linked poly(propylene fumarate)/poly(N-vinyl pyrrolidone) (PPF/PNVP) matrices were studied for their effect on the release kinetics of two ophthalmic drugs. The hydrophilicity of solid PPF/PNVP matrices loaded with acetazolamide (AZ) or timolol maleate (TM) was increased by adding various amounts of poly(ethylene glycol) (PEG) or by increasing the amount of N-vinyl pyrrolidone (NVP) in the polymer mixture prior to cross-linking. The in vitro release studies that utilized high-performance liquid chromatography for quantification revealed highly accelerated drug release from the matrices with increasing contents of the hydrophilic modifier. AZ was released from matrices containing 5% PEG in 56 days, which equals approximately 25% of the release period found for the unmodified matrices. A comparable acceleration in drug release was found for TM-loaded samples modified with 5% PEG. These studies further revealed that 1% PEG is sufficient to shorten the TM release duration by one-third. A significant acceleration in drug release was also found for the samples that were fabricated from a PPF-NVP mixture with increased NVP content. Matrix water content and erosion were assessed gravimetrically. Micro-computed tomography was used to image structural changes of the release systems and shed light on the drug-release mechanism. This study showed that hydrophilic matrix modifications of PPF/PNVP matrices accelerate the drug release of two ophthalmic drugs and represent a suitable tool to adjust drug-release rates from PPF-based matrices for different therapeutic needs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetazolamide / chemistry
  • Acetazolamide / metabolism
  • Antihypertensive Agents / chemistry
  • Antihypertensive Agents / metabolism
  • Diuretics / chemistry
  • Diuretics / metabolism
  • Drug Administration Routes
  • Drug Carriers / chemistry*
  • Drug Delivery Systems*
  • Eye / chemistry
  • Eye / metabolism
  • Fumarates / chemical synthesis
  • Fumarates / chemistry*
  • Molecular Structure
  • Ophthalmic Solutions / chemistry*
  • Ophthalmic Solutions / metabolism
  • Polyethylene Glycols / chemistry
  • Polymers / chemistry*
  • Polypropylenes / chemical synthesis
  • Polypropylenes / chemistry*
  • Timolol / chemistry
  • Timolol / metabolism

Substances

  • Antihypertensive Agents
  • Diuretics
  • Drug Carriers
  • Fumarates
  • Ophthalmic Solutions
  • Polymers
  • Polypropylenes
  • poly(propylene fumarate)
  • Polyethylene Glycols
  • Timolol
  • Acetazolamide