Development and Optimization of Proniosomal Gel Containing Etodolac: In-vitro, Ex-vivo and In-vivo Evaluation

Introduction: Etodolac is used in the treatment of acute pain and inflammation. It has low solubility because of high hydrophobicity and it is reported that upon oral administration shows gastric disturbances. This encourages the development of topical vesicular formulation. Method: In this work we used coacervation-phase separation method for the development of etodolac loaded vesicular system by using non-ionic surfactants, cholesterol and soya lecithin. Central composite design (rotatble) was used to optimize the concentrations of soy lecithin, surfactant and cholesterol. The prepared formulations were characterized by number of vesicles formed, vesicle size, zeta potential, entrapment efficiency, in-vitro permeation, ex-vivo permeation and anti-inflammatory study. Results: Etodolac was successfully entrapped in all formulations having efficiency in the range of 74.36% to 90.85%, which was more at 4 degrees C than room temperature. When hydrated with water; niosome in the range of 54 to 141 (per cubic mm) were spontaneously produced. The results of in-vitro diffusion study revealed that etodolac was released in the range of 71.86 to 97.16% over a period of 24 hrs. The average vesicle size of optimized formulation was found 211.9 nm with PDI of 0.5. The observed responses i.e. % encapsulation efficiency and drug release were 74.12 and 95.08 respectively. The zeta potential was -19.4mV revealed the stability of formulation which was further confirmed by no changes in drug content and drug release after stability studies. The % inhibition in paw volume was 40.52% and 43.61% for test and marketed proniosomal gel. Conclusion: Proniosomal gel formulation was stable and could enhance skin delivery of etodolac because of excellent permeation capability of vesicular system.