Below chart is a reference to AVX tantalum capacitors, notice how temperature has an effect on leakage current. Most manufacturers specify leakage current anywhere from 1-5 minutes of use. Although these formulas appear common across all smaller SMT tantalum capacitors, please review product specific datasheets.
C: refers to the uF rating of the capacitor
V: refers to the rated voltage of the capacitor, not the actual circuit voltage of the capacitor