Lantus is insulin glargine in a concentration of 100U per ml. This means there are 100 units of insulin in every millilitre. Recently a more concentrated version of glargine has been released called Toujeo which has 300units of insulin in every millilitre.
A person on Toujeo insulin would inject the same number of units of insulin but the volume of liquid would only be 30% of the amount of Lantus injected.
As the insulin is more concentrated and a smaller volume is injected this does change some of the characteristics of the insulin and offer some advantages. The advantages of Toujeo U300 over Lantus U100 are as follows:
longer effect
more consistent release into the circulation
20-30% reduction in hypoglcaemia compared to Lantus
Less stinging when injecting
easier to inject and administer