about 45 u00b0 relative to the horizontal plane of the valve stem 24 and the channel opening 50 may measure about 0 25 mm in height and about 160 u00b0 of the valve stem circumference an alternative embodiment may have a channel opening height of about 0 5 mm any channel angle from about 0 u00b0 to and including about 90 u00b0 relative to the horizontal plane of the valve stem may be suitable for a particular application however in an alternative embodiment a channel may intersect with the channel opening 50 at an angle from about 0 u00b0 to about u2212 90 u00b0 with respect to the horizontal plane may be desired in certain embodiments such an embodiment similar to that shown in fig9 may have a channel angle of about u2212 45 u00b0 with respect to the horizontal plane of the valve stem for example drug from a suspension formulation may form a sediment between dosings in the embodiment shown in fig9 such sedimented drug may preferentially collect on the floor of interior space 36 thereby reducing sedimentation of drug in the channels 34 the narrow annular space 32 or both the sedimented drug may be more readily resuspended into the formulation from the floor of the interior space 36 than from either the channels 34 or the narrow annular space 32 when the patient shakes the inhaler thus such a valve stem may promote more consistent accurate dosing and more complete use of drugs in suspension formulations any channel angle from about 0 u00b0 to and including about u2212 90 u00b0 may be suitable for a particular application in certain embodiments one or more edges 72 of the channel opening 50.