Development of Nifedipine-Loaded Nanoemulsions as Inks for Inkjet Printing of a BCS Class II Drug

H. F. Fritz, A. C. Ortiz, J. O. Morales University of Chile Purpose As inks for inkjet printing are aqueous based, BCS class II and IV drugs are difficult to formulate. Nanoemulsions can incorporate poorly water soluble drugs in an oil phase dispersed in an aqueous media. Therefore, the purpose of this investigation was to evaluate the potential of inkjet printing as a means to deposit nanoemulsions loaded with nifedipine (NFD) as a model BCS class II drug. Methods Nanoemulsions were manufactured by the solvent displacement technique. An organic phase composed of lecithin (Epikuron 145v), Miglyol, ethanol and acetone was mixed with water (aqueous phase). Organic solvents were removed by vacuum evaporation and the volume of manufacture was adjusted to 5 mL. NFD-loaded nanoemulsions were obtained by incorporating 1, 10, and 20% w/w (based on the oil phase composed of lecithin and Miglyol) to the organic phase previous to solvent displacement. Two formulations were developed to study the influence of the amount of oil phase, where F2 has about twice the oil phase content compared to F1. The inks were obtained by mixing glycerol and nanoemulsions in a 3/7 ratio. The printing process was conducted in a desktop inkjet printer (HP Deskjet 1000) to various areas on an inert non-wettable surface. The printed ink was collected with either water (for nanoemulsion characterization) or methanol (for NFD quantification) and characterized. The pre and post printing characterizations were size, polydispersity index (PDI), zeta potential (ZP) (Malvern Zetasizer Nano ZS), morphology (SEM), entrapment efficiency, and quantification of printed NFD (UV at 236 nm). Results Figure 1 shows that F2 has a more negative ZP than F1 which is related to the higher lecithin (negatively charged) content that F2 has. Furthermore, a high content of NFD (20%) was associated to less negative ZP. With and without NFD addition, F2 has a consistently larger average size than F1. This was also associated with larger PDI for F2 in comparison with F1. After printing of either 9 cm or 49 cm, average size remains similar in relation to pre-printing conditions. Conversely, ZP shows a slight decrease (to less negative values) although not significantly different (p>0.05) (Figure 2). PDI is lower than 0.160 in every printing condition for F1. Specific printed areas have a NFD amount accounting for more than 50% of process efficiency.