Biopharmaceutical aspects of a chemical approach to drug delivery: macromolecule-drug conjugates

Some recent advances pertaining to the biopharmaceutical aspects of drug delivery are briefly given, followed by a review of the current status of the application of soluble macromolecular carriers for drug delivery. The dextran conjugates were selected as model compounds to demonstrate the implications of the biopharmaceutical approach in the design, evaluation, and delivery of macromolecular conjugates.     

The fate of Depogen in rats.

Studying the metabolism of Depogen in rats we have worked out a method for the purification, isolation and separation of the drug and its potential metabolites. In the basic fraction we have found the same metabolic pathway of Drotaverin published earlier by us. In the focus of our recent work was the fate of the theophylline-7-acetic acid and its eventual biotransformed products. We have stated that theophylline-7-acetic acid contrasts with the theophylline excresa in unchanged form, which has been confirmed by several methods.     

Biopharmaceutical investigation of fenoprofen

The salts of fenoprofen formed with different metals have shown various crystal forms and solubility. The calcium salt has proved the most suitable characteristics for tablet and capsule production. Dissolution and absorption parameters of this substance were studied using in vitro and in vivo methods. The absorption rate and the correlation between pH and membrane diffusion rate constant were investigated in vitro using the "Sartorius" apparatus. The dissolution rate--depending on pH--was investigated by the oscillometric method. The in vivo disintegration of an experimental sample was compared with a commercial preparation. The comparison has been documented by endoscopic photography.