an autoinjector comprising : a first chamber for containing a dry component of a medicament ; a second chamber for containing a wet component of a medicament ; an axially - slidable stopper intermediate said first and second chambers ; an injection needle in fluid communication with said first chamber ; and a transfer needle initially disposed axially forward of said stopper , the transfer needle having a longitudinal axial bore therethrough , a closed forward or proximal end , an open rear or distal end and a radial aperture intermediate said proximal and distal ends and in fluid communication with said longitudinal axial bore ; wherein said transfer needle is capable of penetrating said stopper to establish fluid communication between said first and second chambers via said bore and radial aperture to enable said wet component to mix with said dry component and wherein said injection needle is capable of delivering the mixed dry and wet components of the medicament to an injection site .