InoCure’s researchers are advancing the emulsion electrospinning method for controlled release of biomolecule-based active pharmaceutical ingredients (APIs). Emulsion electrospinning allows the encapsulation of high quantities of the biomolecules in the core of the nanofibers, preserving their structure and activity. For sustained release applications, water in oil emulsions are used. In this case, biomolecules, such as proteins, are dissolved in the water together with other waster soluble molecules. Then the water phase is mixed with the polymers dissolved in organic solvents (e.g. polycaprolactone in chloroform) and emulsified using homogenizers. During the electrospinning, produce water droplets form the core of the nanofibers (red in confocal microscopy images and illustration) which encapsulates and protects the active molecule. The shell of the fibres acts as a barrier, limiting the release of the active molecules. Compared to the coaxial-spinning, high-throughput (5 gr/hr using the lab-scale InoSpin) production of nanofibers is possible. The formulation and the process are developed in three stages:
- Optimization of the emulsion stability. For this, various polymer composition, surfactants and their ratios, preparation methods are being tested. Stability of the emulsion is evaluated visually, by observing the phase separation. The formulation that are sufficiently stable (no signs of separation in one hour) are used for high throughput electrospinning.
- Optimization of the emulsion electrospinning. Stable emulsions are processed into nanofibrous membranes using the high-throughput (>30 ml/hr) emulsion electrospinning. Depending on the formulation, continuous or separated core is formed. The electrospinning process is optimized to ensure maximum fibre homogeneity, and quality.
- Optimization of the release rate. Once suitable electrospinning parameters are found, the formulation is further adjusted to optimize the release rate of the active ingredient. In this case, design of experiment is used to find the optimum ratios of polymers and surfactants to achieve the needed loading and release of the active pharmaceutical ingredient.
The optimized formulation can then be used for encapsulation and delivery of various molecules with only slight adjustments in formulation and process.