Table 6.

Influence of processing, atomization, spray-freezing and SFD on insulin aggregation and degradation determined by size exclusion and reverse-phase chromatography.

insulin formulation	preparation	loss of insulin monomer (%)	A-21-desamido insulin (%)
bulk insulin (unprocessed)	—	—	1.680
insulin after atomization	5 mg ml−1, unformulated at pH 2.0	0.101	1.786
	5 mg ml−1, plus trehalose 5 mg ml−1 at pH 2.0	0.066	1.699
insulin after atomization, freezing and thawing	5 mg ml−1, unformulated at pH 2.0	0.044	1.721
	5 mg ml−1, plus trehalose 5 mg ml−1 at pH 2.0	0.031	1.722
insulin after SFD	5 mg ml−1, unformulated at pH 2.0	0.078	1.795
	5 mg ml−1, plus trehalose 5 mg ml−1 at pH 2.0	0.049	1.779
insulin directly after homogenization in TMDD	pure insulin nanoparticles	0.092	1.799
	insulin–trehalose (1 : 1) nanoparticles	0.075	1.781
formulation 2b		0.104	1.962
formulation 3b		0.095	1.917
formulation 4a		0.114	1.901
formulation 4b		0.095	1.768
formulation 5a		0.098	1.894
formulation 5b		0.120	1.823
formulation 6b		0.123	1.856
formulation 7b		0.110	2.080
formulation 8a		0.094	1.871
formulation 8b		0.089	1.798