A method of preparing a pharmaceutical product comprises the steps of (a) providing a neat active pharmaceutical ingredient (API) complying with at least five of the following parameters determined by using a FT4 powder rheometer: (i) specific basic flow energy of at most 60 mJ/g; (ii) stability index of 0.75 to 1.25; (iii) specific energy of at most 10 mJ/g; (iv) major principle stress at 15 kPa of at most 40; (v) flow function at 15 kPa of at least 1.3; (vi) consolidated bulk density at 15 kPa of at least 0.26 g/mL; (vii) compressibility of at most 47%; and (viii) wall friction angle of at most 40°; (b) dispensing the neat API of step (a) into a bottom part of a pharmaceutical carrier using a vacuum assisted metering and filling device; and (c) encapsulating the bottom part, thereby producing a pharmaceutical product.