Printing of cutaneous patches loaded with propranolol for the treatment of infantile haemangiomas

Topical propranolol has been used in clinics for treating cutaneous infantile haemangiomas, but frequent applications of semi-solid preparations are required to maintain therapeutic drug concentrations in the skin layers over time. This work aims to study the preparation of cutaneous propranolol patches by hot-melt ram extrusion printing, a novel technique suitable for the personalization of the dosage forms. The preparation steps are: i) mixing of a poly-ammonium methacrylate polymer (Eudragit RL) with a suitable amount of plasticizer [acetyl triethyl citrate (ATEC), triacetin or tributyl citrate, TBC] and the drug (propranolol base, or hydrochloride), ii) the melting in the ram extruder, and iii) the printing on the backing layer foil. All formulations released the loaded drug in a reasonable time and exhibited suitable adhesive properties. The determination of permeation profiles of the drug revealed the patch made of Eudragit RL and TBC and containing 1% propranolol hydrochloride as the most promising formulation for ensuring the drug retention on the human epidermis (Qret/J = 1.32) and, therefore, it can be selected when a superficial haemangioma has to be treated. Conversely, the patch made of Eudragit RL and ATEC and 1% propranolol base can be used in the case of deep haemangiomas.