Comparative Release of Phenylpropanolamine HC1 from Long-Acting Appetite Suppressant Products: Acutrim Vs. Dexatrim

Abstract

The release of phenylpropanolamine HC1 from two commercially available long-acting appetite suppressant products, Acutrim and Dexatrim, was evaluated by using a dissolution apparatus modified from the well-calibrated Ghannam-Chien diffusion cells. The solubility profile of phenylpropanolamine showed extreme dependency on pH. The release of phenylpropanolamine from Acutrim tablets was observed to be fairly independent of pH and fluid dynamics, but is affected by the osmotic pressure in the dissolution medium. The release profiles of phenylpropanolamine from both Dexatrim and Acutrim were observed to consist of two stages: an initial, fast-release phase and a sustained-release phase at steady state. While both products achieve 100% release of the loading dose, the sustained-release portion of the phenylpropanolamine dose was observed to release from Acutrim tablets at zero-order kinetics over a 8-hr period, but showed a gradual dissolution from Dexatrim granules for over a 4-hr duration. Therefore, a prolonged release of phenylpropanolamine over the target 16-hr period was achieved by Acutrim tablets, but not by Dexatrim capsules.