Hot-melt extruded drug-loaded rods: evaluation of the mechanical properties for individual dosing via the Solid Dosage Pen

Abstract

Individual dosing of peroral medicines is important for personalised medicine and patient-centred treatment, e.g., of children and the elderly. The Solid Dosage Pen (SDP) offers the opportunity to dose individually by cutting drug-loaded rods into tablet-like slices. The aim of the present study is the systematic evaluation of the mechanical properties of these drug-loaded rods prepared via hot-melt extrusion. The drug-loaded rods contain carbamazepine as a model drug, and polyethylene glycols and poloxamers as excipients. For the evaluation of the mechanical properties of the extrudates, three parameters were considered: tensile strength, E-modulus, and maximum cutting force. To examine the practicability of the device and the formulations for patient-centred treatment, the needed cutting forces were compared to literature data of the manual forces of different age groups. The maximum cutting force and the tensile strength were marginally changed over a storage period of six months (21±0.2 °C, 45% r.H). A tensile strength below 9.1±0.3 MPa and an E-modulus below 135.9±7.2 MPa were found to be valuable thresholds for the applicability by the Solid Dosage Pen. Formulations containing PEG 1500 as additive fulfilled the pharmacopeial requirements containing the content uniformity even for the smallest dose.