6N-2,?2-?Dimethyl-?1-?oxopropyl Adefovir Dipivoxil is an impurity of Adefovir Dipivoxil (A280465) which is used as an oral reverse transcriptase inhibitor in the treatment of hepatitis B. 6N-Hydroxymethyl Adefovir Dipivoxil presence indicates the degradation of Adefovir Dipivoxil under specific conditions suggesting the stability of Adefovir Dipivoxil is compromised under such conditions.