Summary of ID₅₀ values for the inhibition of HIV reverse transcriptase³⁰².

ODN (5′ → 3′)a	ID50 (μM)
[d(C)14]-all-PO	36
[d(C)14]-all-PS	1.7
[d(C)14]-all-SPS	60
[d(C)20]-all-SPS	10
[d(C)10]-all-SPS	220
[d(C)8]-all-SPS	1.2
[d(C)4]-all-SPS	20

^aPO, PS and SPS refer to the phosphodiester, phosphorothioate and phosphorodithioate internucleoside linkages respectively.