Compatibility of the antitumoral β-lapachone with different solid dosage forms excipients

The objective of the present study was to evaluate the compatibility of the beta-lapachone (PLAP), an antitumoral drug in clinical phase, with pharmaceutical excipients of common use including diluents, binders, disintegrants, lubricants and solubilising agents. Differential scanning calorimetry (DSC) was used for a first screening to find small variations in peak temperatures and/or their associated enthalpy for six drug/excipient combinations (magnesium stearate, sodium estearyl fumarate, dicalcium phosphate dihydrate, mannitol, randomized methyl-beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin), which indicate some degree of interaction. Additional studies using Fourier transformed infrared spectroscopy (FTIR), optical microscopy (OM) and heating-cooling DSC (HC-DSC) confirmed the incompatibility of beta LAP with magnesium stearate and dicalcium phosphate dihydrate. Those excipients should be avoided in the development of solid dosage forms. (c) 2007 Elsevier B.V. All rights reserved.