In this work, innovative In Situ Forming Organogels have been developed. They consist for the largest part of peanut oil and a low molecular weight organogelator (12-hydroxystearic acid) as well as a small amount of a water-miscible organic solvent (N-methyl-2-pyrrolidone). The formulation can be applied by means of narrow, patient-friendly cannulas and minimal effort. After injection of the oily solution, the organic solvent diffuses into the surrounding aqueous medium or tissue within a few hours. Consequently, the organogelator precipitates and gels the oil and simultaneously imbeds the active pharmaceutical ingredient (API). Depending on the concentration of the organogelator, the solid depots were degraded in vitro by means of lipase within a period of 1-3 months layer-by-layer and without residue. Peanut oil and organogelator showed no cell toxicity, whereas the solvent had a concentration and exposure-time-dependent impairment on the cells. In vivo, MRI and ultrasound examinations have resulted in a complete degradation of the depots within 3-5 months. Drug therapies in mice showed good compatibility of the developed formulations and a controlled release over 5 months.