Application of a colorimetric technique in quality control for printed pediatric orodispersible drug delivery systems containing propranolol hydrochloride

The feasibility of a colorimetric technique was investigated in CIELAB color space as an analytical quality control method for content uniformity of printed orodispersible pediatric delivery systems. Inkjet printing was utilized to fabricate orodispersibe film formulations containing propranolol hydrochloride in a colored ink base using three different edible substrates. A thin sweetener coating layer of saccharin was successfully included in the final dosage forms for palatability purposes using a casting knife. Optical microscopy, scanning electron microscopy and scanning white light interferometry analyses were conducted to study the effect of printing on the surface morphology and topography of the substrates. Differential scanning calorimetry and attenuated total reflectance infrared spectroscopy were used to study the solid state properties and possible interactions between the drug and the excipients. The inkjet printing technique deposited precise and uniform escalating doses (0.08⿿3.16 mg) of the active pharmaceutical ingredient onto the substrates (R² ⿥ 0.9934). A disintegration test with clear end-point detection confirmed that all the substrates meet the requirements of the Ph. Eur. to disintegrate within 180 s. The colorimetric technique proved to be a reliable method to distinguish the small color differences between formulations containing an escalating dose of propranolol hydrochloride.