Inkjet printing of oral dosage forms to solubilize BCS Class II drugs

Oral drug delivery remains the preferred method of administration but BCS Class II drugs are not ideally suited to this due to their inherent poor solubility. Although a number of methods to increase solubility already exist, there is a need for less damaging methods of production which are more flexible to the needs of the patient. The innovative formulation method of inkjet printing has been suggested for this purpose as it has the capacity to produce highly precise dosing in a continuous manner. The Optomec Aerosol Jet 200 Printer utilised in the current study has never been used in pharmaceutical research before and it is highly interesting as it functions in a manner akin to a miniaturised spray dryer. Due to the low dose content of a single layer, formulations can be easily tailored to the patient’s individual requirements by changing the size and speed of deposition, utilising different nozzle sizes and layering to increase the overall dose. Raman spectroscopy, scanning electron microscopy and powder x-ray diffraction suggest that printing the drug alone results in a crystalline product. However, in the presence of a polymer it seems to form a less crystalline product suggesting the polymer is promoting solid dispersion formation in a similar manner to a spray dryer. Completely amorphous formulations are achieved on application of a premixed "ink" with a polymer content of 75% or more, allowing up to 25% drug loading. Drug release increases 10-fold on printing relative to a comparable powder blend and thus inkjet printing can be considered to be a viable method of improving the overall performance of the drug. The next steps will be to utilize this established methodology to produce innovative controlled release on a small scale.