Abstract
Purpose: :
Objective of the study was developing a new Hydrocortisone/Hyaluronic Acid (MDV/HA) low-viscosity topical ophthalmic formulation highly mucoadhesive on the ocular surface.
Methods: :
Two formulations based on 0.335% Hydrocortisone (HY) sodium phosphate were prepared: MDV (containing the corticosteroid in phosphate buffer) and MDV/HA (containing the active principle in phosphate buffer plus a 0.05% high M.W. Hyaluronic Acid). Precorneal Residence Time (PRT) of MDV and MDV/HA were measured, after instillation of the drugs in the conjunctival sac of rabbits, by means of UV Reflectance Spectroscopy technique. In order to evaluate the influence of mucoadhesivity, experiments were conducted both in normal rabbits and rabbits pre-treated topically with N-acetylcysteine, a well known mucolytic agent.
Results: :
Hydrocortisone in the Hyaluronic Acid formulation (MDV/HA, viscosity=2.46 mPas) showed a PRT of 1825+150 sec in the normal rabbits and 550+75 sec in the N-acetylcysteine pre-treated animals. Without the HA mucoadhesive polymer, Hydrocortisone in phosphate buffer solution (MDV) had a PRT of 350+50 sec and 275+42 sec respectively. HA increased by 5.2 times the PRT of HY formulation. The mucoadhesivity was responsible for 86% of the increase of PRT while viscosity for 14%.
Conclusions: :
The highly mucoadhesive Hydrocortisone/Hyaluronic Acid topical association, showing a surprisingly long Precorneal Residence Time, could find application in the treatment of ocular surface irritation/inflammation when a soft steroid is suggested.
Keywords: corticosteroids • anterior segment • inflammation