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Elimination of hydroxypropyl methylcellulose from the anterior chamber of the rabbit
J Fernandez-Vigo1, M F Refojo, M Jumblatt
1Eye Research Institute, Harvard Medical School, Boston, Massachusetts 02114.
Abstract:
The elimination of hydroxypropyl methylcellulose (HPMC) of molecular weight 86,000 daltons (2%, viscosity 4,000 centipoises; 2.5%, 15,000 centipoises) and 120,000 daltons (2%, 15,000 centipoises) from the anterior chamber of rabbit eyes was determined colorimetrically and was nearly complete by 24 hours. The elimination rate was dependent on the viscosity of the HPMC injected into the eye. Elevation of the intraocular pressure by HPMC was detected three hours after injection, but the pressure was almost normal at six hours and was normal thereafter. This effect is independent of the molecular weight, the concentration, and the viscosity of the solutions used. Using an in vitro assay method, HPMC (86,000 daltons) at 2.5% concentration in tissue culture medium was innocuous to rabbit endothelial cells.
Insights
Hydroxypropyl methylcellulose (HPMC) was rapidly eliminated from rabbit eyes within 24 hours, with elimination rates depending on viscosity. Temporary intraocular pressure increases were observed but normalized quickly.
Area of Science:
- Ophthalmology
- Biomaterials Science
- Pharmacokinetics
Background:
- Hydroxypropyl methylcellulose (HPMC) is a common excipient in ophthalmic formulations.
- Understanding its behavior in the anterior chamber is crucial for drug delivery and ocular safety.
Purpose of the Study:
- To investigate the elimination kinetics of HPMC from the anterior chamber of rabbit eyes.
- To assess the impact of HPMC on intraocular pressure and ocular tissue safety.
Main Methods:
- Colorimetric determination of HPMC elimination from rabbit anterior chambers.
- Measurement of intraocular pressure post-injection.
- In vitro assessment of HPMC cytotoxicity on rabbit endothelial cells.
Main Results:
- HPMC elimination was nearly complete within 24 hours, with rates dependent on viscosity.
- A transient increase in intraocular pressure was noted at 3 hours, normalizing by 6 hours.
- HPMC at 2.5% concentration was found to be non-toxic to rabbit endothelial cells in vitro.
Conclusions:
- HPMC exhibits favorable elimination profiles from the anterior chamber.
- HPMC demonstrates a transient and reversible effect on intraocular pressure.
- HPMC shows good ocular tissue compatibility, supporting its use in ophthalmic applications.