Processes for making a diester compound of formula and for converting it to pregabalin, especially via a compound of formula, can provide several advantages. In the exemplary embodiment an object is placed on a rotating turntable and a camera, which is stationary, captures images of the object as it rotates on the turntable. The initial dosage stage comprises infusing the active agent at an initial dosage rate for an initial period to achieve a target steady state blood plasma concentration of the active agent or metabolite thereof. The arrangement order of the first and second sustain electrodes may preferably be such that first sustain electrodes of the first and second partial screens face each other via the border line, and the partial address electrodes may not cross over the first sustain electrodes nearest to the border line.