Confocal Raman and Electron Microscopy Analysis of Ophthalmic Implants

Ophthalmic implants, also known as ocular implants, can be used to deliver therapeutics more effectively or to improve or return vision to patients. Ocular implants include prosthetic eyes, artificial lenses, drainage implants (tube shunts), and more.

A manufacturer of ophthalmic implants contacted us to compare two formulations that they were considering, and we did so by looking at the cross section component distributions and coating surface morphologies.

The work that was done on this project was presented at the 38^th Annual Meeting and Exposition of the Controlled Release Society at the National Harbor, Maryland USA. The poster presents the analysis of ophthalmic controlled release implants using confocal Raman microscopy (CRM) and scanning electron microscopy (SEM).

Introduction:

Ophthalmic implants and anti-fungal injection products were evaluated by confocal Raman microscopy (CRM) and scanning electron microscopy (SEM). CRM was used to determine the distribution of excipients and the active pharmaceutical ingredient (API) in the ophthalmic device; SEM was used to investigate the morphology and migration of the API. Drug distribution of the anti-fungal injection device was conducted using SEM, and the evaluation of possible polymorphic forms of the API were investigated using CRM.

Methods:

The ophthalmic device was freeze fractured and the cross section was analyzed with a WITec alpha 300R confocal Raman microscope equipped with a 532 nm laser and a JEOL 6500 field emission scanning electron microscope at magnifications ranging from 250x to 10,000x. The anti-fungal implants were coated in cyanoacrylate glue or gold. The coated samples were mounted in epoxy then sectioned with a Reichert Jung Ultracut E ultramicrotome.

Conclusion:

• Confocal Raman microscopy provided detailed information about the distribution of each component within the formulated products.
• Scanning electron microscopy with energy dispersive x-ray spectrometry revealed information about the morphology and chemistry of the two products.
• Complementary techniques in the investigation of controlled release products provided extensive information about the microenvironments such as morphology, elemental composition, distribution of ingredients, and variations of the API due to polymorphism or orientation effects.

For more information about implants analysis, our techniques or instrumentation, please contact us at 770-662-8509 or info@mvainc.com