The invention provides microparticles comprising an immunosuppressant, such as tacrolimus, sirolimus, pimecrolimus, ciclosporin, everolimus or a derivative thereof, and optionally a pharmaceutically acceptable excipient or carrier, such as a saccharide, amino acid, a sugar alcohol or a mixture thereof, and having a median geometric diameter of less than, or equal to, about 10 &mum and which have a tap density of less than or equal to about 0.3 g/cm3.
