Availability of phendimetrazine from sustained and non-sustained action formulations

Two tablet formulations of d-phendimetrazine bitartrate, Obex (35 mg non-sustained action) and Obex-LA (105 my sustained action), were compared in terms of biological availability in 9 volunteers on the basis of serum level findings. The ratio of the areas under the absorption and elimination curves was 1:2,2 (Obex:Oves-LA), indicating that the biological availability of phendimetrazine from Obex-LA was plus or minus 70% of that from Obex. The elimination half-life of phendimetrazine was found to be 9,1 hours. An evaluation of appetite suppression revealed that the two formulations were equally effective at breakfast and at dinner, with Obex-LA significantly superior to Obex at lunch.