Distribution of drugs in polymers loaded by swelling

Ethylene vinyl acetate pellets were loaded by swelling with chloroformic solutions of tolbutamide. The energy dispersive X-ray analysis showed different concentrations of the tolbutamide sulfur in the pellet sections according to the loading time. The concentration peaks might depend on a drug sieving process as the solution flow reaches a less swollen inner area. Another possible explanation of these concentration profiles is that they could be a result of thesolvent evaporation process. The concentration distribution of the drug becomes homogenous only after the complete swelling of all the polymer.