Abstract: A method and apparatus for producing a pharmaceutical product in a micronised form. The pharmaceutical product is delivered at a predetermined flow rate from a gravimetric feeding device into a delivery line. An air compressor generates an air stream which is delivered along an airline into which the pharmaceutical product delivery line is discharged for delivering the product to a microniser which micronises the product to a desired size range. The micronised product is delivered through a cyclone filter apparatus from which the micronised product is collected through an outlet valve to a storage drum.