Study of the aggregation of insulin glargine by light scattering

Insulin glargine (Lantus1, Aventis Pharma, Deutschland, GmbH) is a new long-acting human insulin analog. Structural modification of the insulin molecule at two sites alters its pH, causing insulin glargine to precipitate in the neutral environment of subcutaneous tissue and to form a depot that is slowly absorbed into the bloodstream. In this paper insulin glargine aggregation is investigated by light scattering. This study shows that, in a physiologic-like pH (even at low ionic strength) conditions, aggregation phenomena occur, giving rise to compact structures with radius of hundreds of nanometers. The aggregation of insulin glargine can be responsible for its slow in situ absorption allowing for a more controlled release.