The invention provides a drug delivery vehicle for inhalation by a patient. The drug delivery vehicle comprises biocompatible particles between 0.1 and 1.0 microns in diameter, that are loaded with one or more drugs and which are crosslinked together to form agglomerates. The agglomerates can also provide for delivery of contrast-enhancing agents for clinical imaging. The invention also provides methods of making the inventive agglomerates, pharmaceutical compositions comprising the agglomerates, and methods for delivering drugs or contrast-enhancing agents to a patient by inhalation of pharmaceutical compositions containing the agglomerates.