There is described formulations for human or animal administration and to a method of preparation thereof. In particular, there is described more stable pharmaceutical formulations, such as those for intravenous administration, and to a method of preparation thereof. There are also described lyophilised formulations having an active pharmaceutical ingredient (API), a buffering agent and a lyoprotectant, wherein the API is an imaging agent comprising at least one cMet binding peptide, suitable for optically imaging the mammalian body in vivo. Also described are a method of preparing a lyophilised formulation, a pharmaceutical composition, and a kit for the preparation of the pharmaceutical composition. Further described are methods of imaging using the formulation or pharmaceutical composition, such as in detection, diagnosis, surgery, staging, treatment, monitoring of treatment, monitoring of disease progression or monitoring therapy of conditions such as cancer.
