Formulation of Levofloxacin Loaded Niosomal suspensions as an Ocular Delivery System: In-Vitro Evaluation and Microbiological Study

INTRODUCTION Levofloxacin hemihydrate is a fluoroqinolone antibiotic with broad spectrum antibacterial agent. Encapsulation of the drug into vesicular system provides delivering drug in a controlled manner to enhance... [ view full abstract ]

INTRODUCTION
Levofloxacin hemihydrate is a fluoroqinolone antibiotic with broad spectrum antibacterial agent. Encapsulation of the drug into vesicular system provides delivering drug in a controlled manner to enhance bioavailability and get therapeutic effect over a longer period of time. Niosomes are such hydrated vesicular systems containing nonionic surfactants along with cholesterol or other lipids delivering drug to targeted site which are non toxic, requiring less production cost, stable over a long period of time in different conditions.

METHODS
Niosomes of levofloxacin hemihydrate were prepared by reverse evaporation method.Optimization of the formulation step was carried by application of 5x3x2 factorial design to study the influence of three parameters including surfactant type , cholesterol molar ratio and surfactant molar ratio on the physicochemical properties including particle size , entrapment effeciency (E.E) and release parameters (Q8h and Q24h ). Transmission electron microscope (TEM) was carried out for the selected formula. Microbiological study of the selected formula was also investigated.

RESULTS AND DISCUSSION
Niosomes prepared from span 40 and span60 showed the highest entrapment efficiency. The best formula was the one which prepared from span60 and cholesterol with molar ratio(7:6) of entrapment efficiency 84.1% and particle size (587nm). In-vitro drug release results confirmed that niosomal formulations have exhibited a high retention of levofloxacin inside the vesicles and can sustain release up to 24 hours. The in-vitro evaluation of levofloxacin hemihydrate niosomes in comparison to levofloxacin hemihydrate solution showed the effect of niosomes in prolongation of drug release from the ocular delivery system. Niosomes may be considered as promising ophthalmic carriers for the topical application of levofloxacin hemihydrates .The antimicrobial activity of the selected formula was retained up to 24 hours