Doripenem appears as crystalline powder, with colour anywhere from a white to somewhat yellowish. Doripenem is moderately soluble in water, slightly soluble in methanol, and virtually insoluble in ethanol. Doripenem is also soluble in N,N-dimethylformamide. Doripenem's chemical configuration has 6 asymmetrical carbon atoms (6 stereocentres) and is most commonly supplied as one pure isomer. In terms of doripenem for injection, the crystallized powdered drug can form a monohydrate when mixed with water. However, doripenem has not been proven to possess polymorphism.
These receptors, like those in the heart, are coupled to a Gs-protein , which stimulates the formation of cAMP . Although increased cAMP enhances cardiac myocyte contraction (see above), in vascular smooth muscle an increase in cAMP leads to smooth muscle relaxation. The reason for this is that cAMP inhibits myosin light chain kinase that is responsible for phosphorylating smooth muscle myosin. Therefore, increases in intracellular cAMP caused by β 2 -agonists inhibits myosin light chain kinase thereby producing less contractile force (., promoting relaxation).