1. Nurul Hafizah Mohd Nor, Nur Azhani Zainol Abidin, Nur Liyana Mohd Fozi, Nur Sulaihah Omar & Farahidah Mohamed Pharmaceutical Technology Department, Kulliyyah of Pharmacy, International Islamic University Malaysia Email: farahidah@iium.edu.my 1. To develop an oil-in-water (o/w) Nigella sativa microemulsion (ME) 2. To improve ME’s aqueous solubility and uptake by PC12 cell line 3. To investigate in vitro effect of N. sativa in exerting neurite outgrowth on aqueous environment of PC12 cell line OBJECTIVES ABSTRACT The aims of this project were to develop the oil-in-water (o/w) Nigella sativa microemulsion in order to improve its aqueous solubility and hence uptake by PC12 cell lines. Such system was envisaged to be feasibly used to see in vitro effect of N. sativa in exerting neurite outgrowth on aqueous environment of PC12. The microemulsion (ME), prepared by spontaneous emulsification method, composed of varying pre-determined volumes of the N. sativa oil and sorbitan-based surfactant blends, were titrated against water until either turbidity or clear translucent phase were formed. Corresponding volumes of the 3 components were plotted into a phase diagram. All translucent mixtures were characterized for their viscosity and droplet size. Further stability tests on the microemulsions were also conducted following storage at room temperature, heating and centrifugation. Results showed that droplet diameters of ME 12 (9.09% oil, 72.73% Tween20:Tween80 (6:4), 18.18% water), ME 13 (10.71% oil, 71.43% Tween20:Tween80 (6:4), 17.86% water) and ME 14 (7.41% oil, 74.07% Tween20:Tween80 (6:4), 18.52% water) were 24.18 nm, 14.96 nm and 46.86 nm respectively and gave transparent solution with no turbidity after being subjected to vortex mixer. Subsequent analysis will involve loading of these microemulsion into PC12 cell line to see the effect of N. sativa oil in exerting neurite extension. This approach seems to be potentially useful for in vitro rapid screening study of lipophilic agent that involves aqueous cell lines. The authors would like to thank Ministry of Science, Technology and Innovation Malaysia (MOSTI) for the funds, IIUM and all laboratory staffs. CONCLUSION This approach seems to be potentially used for in vitro rapid screening study of lipophilic agent that involves aqueous cell lines. Stable N. Sativa oil-in-water microemulsion had been successfully produced by appropriate blending of surfactant types with the N. sativa oil and water. The findings also suggest that range of HLB ratio for similar surfactant groups could be utilized as guideline to find correct ratio between the ternary components RESULT Table 1 Table shows the evaluation of N. sativa oil in water-based media microemulsion formulations Figure 1 It shows the pseudoternary diagram of N. sativa microemulsions Table 2 Table shows the physical characteristic of N. sativa oil in water-based media microemulsion formulations Table 3 Table shows the stress-testing for phase separation of N. sativa microemulsions. Figure 2 It shows the neurite outgrowth of PC12 cell line 96H post-treatment with ME12, ME13 and ME14 Translucent phase were formed Spontaneous emulsification method Figure 3 It shows the neurite extension of PC12 cell line 96H post-treatment with ME12, ME13 and ME14 ACKNOWLEDGEMENT REFERENCE DISCUSSION 1. Bagwe, R.P., Kanicky, J.R., Palla J., Patanjali, P.K., Shah, D.O., Improved Drug Delivery Using Microemulsion: Rationale, Recent Progress, and New Horizons, Critical Reviews in Therapeutic Drug Carrier Systems, 18(1), pp. 77-140, 2001. ME formulation of 12, 13 and 14 were closely spotted near to the upper left of the phase region, concluding that these formulations were oil in water ME corresponding to the hypothetical phase pseudoternary diagram. They also exhibited less than 100 nm range of particle size. After stress testing, no significant changes in the phase separation, meaning no changes in the structures of the non-ionic surfactants, thus ME remained stable. For neurite outgrowth; at low concentration, no changes were observed. At high concentration, bipolar & multipolar neurite extensions appeared longer in length grown individually, indicating ME stimulated neurite entension. PREPARATION AND CHARACTERIZATION OF NIGELLA SATIVA MICROEMULSION INTENDED FOR NEURITE OUTGROWTH STUDY ON PC12 CELL LINE METHODOLOGY