The present invention relates to a modified-release, once-daily, oral pharmaceutical composition comprising isotretinoin and a process for its preparation. In some embodiments, the disclosure is directed to a modified-release, oral pharmaceutical composition comprising isotretinoin or a pharmaceutically acceptable salt, ester or a derivative thereof; and a release modifying agent, wherein the composition is suitable for once daily administration. In some embodiments, the disclosure is directed to a modified-release, oral pharmaceutical composition comprising isotretinoin, wherein the composition comprises an immediate-release component; and a modified-release component comprising a release modifying agent, and wherein the composition is suitable for once daily administration.La présente invention concerne une composition pharmaceutique orale à dosage quotidien unique d'isotrétinoïne et son procédé de préparation.