Ultrasound-compacted and spray-congealed indomethacin/polyethyleneglycol systems.
The product obtained by ultrasound (US)-assisted compaction was compared with a solid dispersion for systems containing polyethyleneglycols (PEGs) of different molecular weights and indomethacin (IMC), at the weight ratio 9:1, obtained by traditional melting and followed by a new US-assisted spray-congealing technique. US-discharge during compaction affects crystallinity of both IMC and PEG: pure IMC changes to an amorphous form and, when in mixture with PEG, partially dissolves in the excipient: this causes an increase of the dissolution rate of the drug. Differential scanning calorimetry (DSC) thermograms do not reveal any endothermic peak associated with the melting of the drug, while X-ray diffractograms show a loss of crystallinity of both IMC and PEG in the US-compacted granules. The extent of a back-crystallisation, which reduces the dissolution rate, as a function of the ageing of the material, depends on the type of the selected PEG. When a molten IMC/PEG mixture was transformed into microspheres by an US-assisted spray-congealing technique, the behaviour at dissolution almost recalls that of US-compacted granulates and some differences are briefly discussed.
Fini
A
A
Istituto di Scienze Chimiche, Università di Bologna, Via San Donato 15, Bologna 40127, Italy. fini@biocfarm.unibo.it
Rodriguez
L
L
Cavallari
C
C
Albertini
B
B
Passerini
N
N
D002626:Chemistry, Pharmaceutical; D007213:Indomethacin / Q000138:chemical synthesis / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry*; D012995:Solubility; D013678:Technology, Pharmaceutical / Q000379:methods*; D014465:Ultrasonics
D011092:Polyethylene Glycols; D007213:Indomethacin