Acyclovir-containing liposomes for potential ocular delivery. Corneal penetration and absorption

Area of Science:

• Ophthalmology
• Pharmaceutics
• Drug Delivery Systems

Background:

• Acyclovir is a key antiviral medication for ocular infections.
• Improving ocular drug delivery, particularly to the cornea, remains a challenge.
• Liposomes offer potential for enhanced drug delivery, but their corneal interaction needs optimization.

Purpose of the Study:

• To investigate the in vitro corneal penetration and in vivo corneal absorption of acyclovir from liposome systems.
• To evaluate the effect of liposome charge on acyclovir corneal deposition and residence time.
• To determine if positively charged liposomes improve acyclovir bioavailability in the cornea.

Main Methods:

• In vitro corneal penetration assays using acyclovir-loaded liposomes (positively charged, negatively charged) and free acyclovir solution.
• In vivo corneal absorption studies in animal models.
• Corneal concentration measurements of acyclovir post-administration.
• Morphological examination of corneal surfaces treated with different liposome formulations.

Main Results:

• In vitro studies showed lower penetration rates for positively charged liposomes compared to negatively charged ones and free acyclovir.
• In vivo studies demonstrated significantly higher acyclovir absorption and corneal deposition with positively charged liposomes.
• Morphological analysis revealed that positively charged liposomes form a stable coating on the cornea, increasing residence time.

Conclusions:

• Positively charged liposomes enhance acyclovir corneal absorption and deposition.
• The increased residence time of positively charged liposomes on the cornea is the likely mechanism for improved absorption.
• This liposomal formulation represents a promising strategy for enhanced ocular acyclovir delivery.