in wound care treatment Nanostructured lipid carrier: a promising topical system for delivering cinnamon oil in wound care treatment Ming Ming Wen 1, Sally A. El-Zahaby 1, Ibrahim A. Abdelwahab2   1 Department of Pharmaceutics & Pharmaceutical Technology, Faculty of Pharmacy & Drug Manufacturing, Pharos University in Alexandria, Alexandria, Egypt. 2 Department of Microbiology and Immunology, Faculty of Pharmacy & Drug Manufacturing, Pharos University in Alexandria, Alexandria, Egypt. 1. INTRODUCTION OBJECTIVE The aim of this study is to extract cinnamon oil as an antimicrobial agent for further developing NLC as a potential topical delivery system for wound care treatment. There is a growing interest in clinical use of natural products against antibiotic resistant pathogens due to misuse/overuse of antibiotics. Cinnamon oil was used since antiquity as antimicrobial, antidiabetic, and antioxidant. In addition, it has been used for the treatment of arthritis, blood circulation disturbance, dyspepsia, gastritis, and inflammatory diseases. Nanostructured lipid carrier (NLC) is a nanosized drug delivery system representing an improved generation of lipid nanoparticles which composes of a mixture of solid and liquid lipids and stabilized by surfactants in an aqueous phase. The specific nanostructure offers better drug delivery and skin permeation. 2.3. CONSTRUCTION OF FACTORIAL DESIGN A 23 full factorial design was performed using Design-Expert® software (Version 8, Stat- Ease Inc., Minneapolis, Minnesota, USA) for the optimization of the NLC which were formulated using Precirol ATO-5 as solid lipid and labrafac as liquid lipid together with cinnamon oil. Tween 80 was used as surfactant. Table 1 showed the parameters of independent and dependent variables. ANOVA analysis was used in order to analyze the experimental trials so that the optimized formulation could be successfully estimated. Cinnamon oil loaded NLC were prepared by varying the solid/liquid lipids ratio from 1: 1 to 5: 1 with total lipids concentrations ranged from 10-20 % W/W. Tween 80 was used in the concentrations range 0.5-3% W/W. Figure 1: Effect of SAA Concentration along with Total lipids Concentration on PS of NLC Figure 2: Effect of SAA Concentration along with Solid: liquid lipids ratios on PS of NLC 2. METHODS 2.1. EXTRACTION OF CINNAMON OIL The essential oil of cinnamon was extracted from the dried inner bark of the shoots grown on cut stock of Cinnamomum zeylanicum. The hydrodistillation method was used by aid of Clevenger-type apparatus. The antimicrobial activities of cinnamon oil was then tested against clinically isolated multidrug resistant strains of Pseudomonas aeruginosa and Burkholderia cepacia complex. As shown in Figures 1 & 2, as the total lipids concentration increased the PS had decreased. Furthermore, increasing the SAA concentration had also resulted in PS decrease. 4. CONCLUSIONS This study introduced a promising natural product in the fight against antibiotic resistance strains of Pseudomonas aeruginosa and Burkholderia cepacia complex. Delivering cinnamon oil by nanostructured lipid carrier may offer a novel opportunity to enhance skin permeation through nanotechnology based system and achieve faster cure for wound infections by avoiding antibiotic resistance problems. 2.2. PREPARATION OF NANOSTRUCTURED LIPID CARRIER (NLC) 3. RESULTS NLCs were prepared by hot homogenization/ultrasonication methods. Lipid phase containing Precirol ATO-5, Labrafac and Cinnamon oil was heated to 60o C at 600 rpm with a magnetic stirrer. The aqueous surfactant phase containing Tween 80 was heated to the same temperature and then added to the lipid phase dropwisely under high speed homogenizer at 20,000 rpm for 10 min. The obtained emulsions were further sonicated for 5 min at 60o C. The hot NLC dispersion was allowed to drop to room temperature under mild stirring at 600 rpm overnight. The major volatile oil constituents isolated from cinnamon were Cinnamaldehyde, Cinnamic acid, Cinnamyl acetate, Eugenol, α-Thujene, Terpinolene and α-Terpineol. Cinnamon oil showed a significant antibacterial activity against Pseudomonas aeruginosa and Burkholderia cepacia complex. Results in Table 2 showed that the optimal NLC formulation (C3, where the ratio of solid: liquid lipids was 1:1, the total lipids concentration was 10% W/W and percentage of Tween 80 in aqueous phase was 3%) had the smallest size (136.5 ± 0.1 nm) with an acceptable ZP value of -35.5 mV. 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