Question about esterification of racetams? lipid solubility

My question is somewhat specific really tried to answer it with Google but I dont know anything even the most basic stuff about chemistry. Why cant or can levetiracetam become a lipid soluable ester? is the OH group like in testosterone required to under esterifaction with fatty acids? are there other options to increase lipophilicity to make a racetam drug into a long acting injectable solution? really confused why there are no once monthly weekly etc. options for epilepsy