Lantus SoloStar 100units/ml is a brand name for insulin glargine, which is a long-acting insulin used to control high blood sugar levels in people with type 1 and type 2 diabetes. It is given by injection under the skin once daily at the same time each day. The SoloStar pen is a pre-filled, disposable pen that contains 3 ml (300 units) of insulin glargine. The pen has an adjustable dial that allows for accurate dosing and is easy to use. Lantus SoloStar is manufactured by Sanofi-Aventis.