Availability of methaqualone from commercial preparations: in vitro and in vivo studies in man.

1 The plasma profiles of methaqualone obtained from different commercially available preparations have been compared. Tablets were absorbed more efficiently than capsules. Mandrax preparations achieved much higher plasma levels than Melsedin tablets or the Melsed or Sedaquin capsules. These differences appear to be due to formulation factors. 2 The efficacy of the different drugs as hypnotics corresponded well with the blood levels achieved. 3 There was a significant correlation between the in vitro l/t(50%) and the in vivo peak plasma levels. Thus in vitro dissolution studies can be used to predict the efficiency of absorption of different formulations in man.