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

The objective of the present study was to evaluate the compatibility of the beta-lapachone (betaLAP), 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 betaLAP with magnesium stearate and dicalcium phosphate dihydrate. Those excipients should be avoided in the development of solid dosage forms.