Production of ibuprofen in crystalline and amorphous forms by Pulsed Laser Deposition (PLD)

We studied the applicability of Pulsed Laser Deposition (PLD) as a particle engineering method in the field of drug preformulation. Improving the dissolution and thereby the bioavailability of poorly water-soluble compounds is still a challenging task in pharmaceutical formulation. It was shown earlier that particle size reduction or the development of stable amorphous forms may both facilitate drug absorption. Using ibuprofen as a model drug, we studied the ablated particles obtained by pulsed-laser-beam irradiation of ibuprofen tablets. Nanosecond and femtosecond laser pulses (KrF excimer laser, λ = 248 nm, FWHM = 18 ns; 600 fs) were applied at various ambient pressures (10⁻⁴ mbar to 1 bar). The ablated particles were deposited for further analysis by FTIR, Raman Spectroscopy, XRPD, DSC and SEM. We found that all deposits prepared in vacuum by ns-pulses were chemically identical with ibuprofen, but their morphology varied depending on the applied pressure. At higher pressures (10 mbar to 10⁻¹ mbar) the deposits exhibited similar crystalline morphology as the initial ibuprofen, while at lower pressures (10⁻² mbar to 10⁻³ mbar), the deposits were rather amorphous. Using fs-pulses, molecular decomposition occurred at all background pressures. We have established that PLD with ns-pulses is a promising technique in the field of drug preformulation.