Formulation and Evaluation of a Novel In Situ Gum Based Ophthalmic Drug Delivery System of Linezolid

Shivanand Swamy P Hiremath

doi:10.3797/scipharm.0803-17

Abstract

Abstract A major problem in ocular therapeutics is the attainment of optimal drug concentration at the site of action, which is compromised mainly due to precorneal loss resulting in only a small fraction of the drug being ocularly absorbed [1]. The effective dose administered may be altered by increasing the retention time of medication into the eye by using in situ gel forming systems. The aim of the present investigation is to prepare and evaluate novel in situ gum based ophthalmic drug delivery system of linezolid. Hydroxypropyl guar (HPG) and xanthum (XG) were used as gum with the combination of hydroxyethyl cellulose (HEC), carbopol (CP), and sodium alginate as viscosity enhancing agents. Suitable concentrations of buffering agents were used to adjust the pH to 7.4. All the formulations were sterilized in an autoclave at 121°C for 15mins. The formulations were evaluated for clarity, pH measurement, gelling capacity, drug content estimation, rheological study, in vitro diffusion study, antibacterial activity, isotonicity testing, eye irritation testing. The developed formulations exhibited sustained release of drug from formulation over a period of 6hr thus increasing residence time of the drug. The optimized formulations were tested for eye irritation on albino rabbit (male) using the Draize test protocol with crossover studies. The formulations were found to be non-irritating with no ocular damage or abnormal clinical signs to the cornea, iris or conjunctiva observed. Thus these in situ gelling systems containing gums may be a valuable alternative to the conventional systems.

Highlights

Ophthalmic drug delivery is one of the most interesting and challenging factors facing the pharmaceutical research scientist [1, 2]
The prepared in situ gel formulations were evaluated for clarity, pH measurement, gelling capacity, drug content estimation, rheological study, in vitro diffusion study
The combination of and appropriate ratio of hydroxypropyl guar, xanthan:polymers is an important factor in achieving increased duration of action and release from the dosage form to achieve sustained effect

Summary

Introduction

Ophthalmic drug delivery is one of the most interesting and challenging factors facing the pharmaceutical research scientist [1, 2]. The challenge to the formulator is to circumvent the protective barriers of the eye without causing permanent tissue damage [3]. The development of newer, more sensitive diagnostic techniques and therapeutic agents render urgency to the development of more successful ocular delivery systems. The primitive ophthalmic solution, suspension, and ointment dosage forms are clearly no longer sufficient to combat these diseases, and current research and development efforts to design better therapeutic systems are the primary focus of this research work. The aim of the present investigation is to formulate an in situ gel using novel gum system. In situ gel solution increases the residence time and sustain the release mechanism of the drug

Results

Discussion

Conclusion