1-O-hexadecylpropanediol-CDV 3-((2S)-2-{[(3-Hexadecyloxypropoxy)(hydroxyphosphoryl)]methoxy}-3-hydroxypropyl)-6-amino-3-hydropyrimidin-2-one AIDS-104906 AIDS104906 HDP-CDV HDP-HPMPC Hexadecyloxypropyl-cidofovir