Effects of ultrasound-assisted compaction on Ketoprofen Eudragit (R) S100 mixtures

Ketoprofen alone and in binary mixtures with Eudragit(R) S100 was compacted by an ultrasound-assisted (US) tableting machine at an energy ranging from 50 to 400 J. The final material was analysed by TLC and HPLC: no decomposi tion product of the active agent was found. IR spectra and HSM revealed the absence of any interaction between the two components. Thermal analysis (D SC) evidenced that ketoprofen inside the mixtures was transformed into an a morphous state, documented by the decreasing of the Delta H-fus as the Eudr agit(R)/ketoprofen ratio increases and as US energy increases. While pure k etoprofen recovers its crystalline state quickly after the US treatment, th e presence of Eudragit(R) was found to slow down or possibly to prevent the regeneration of the crystallinity. (C) 1999 Elsevier Science B.V. All righ ts reserved.