ABSTRACT
AIM: The aim of the study was to prepare a drug-entrapped, beaded form of blood plasma for possible sustained drug delivery. METHOD: Blood plasma mixed with various drugs was enriched with CaCl2 and transferred in the form of small droplets on to a glass slide covered with parafilm. Clot formation was induced by incubation at 37 degrees C. RESULTS: Plasma-bead entrapped tetracycline, amphotericin B and daunorubicin were released gradually in vitro. Crosslinking of the beads with glutaraldehyde decreased the release rate of drugs remarkably. The plasma bead-entrapped cefotaxime administered subcutaneously in mice was released in a slow and sustained fashion and remained in circulation for a longer duration than the antibiotic administered in the free form. CONCLUSION: The plasma beads have potential for the sustained delivery of drugs in vivo, since their preparation does not require additional thrombin or other proteins and can be readily accomplished by using autologous plasma, thereby minimizing the risk of immunological complications.
Subject(s)
Anti-Bacterial Agents/administration & dosage , Drug Delivery Systems , Animals , Delayed-Action Preparations , Mice , Mice, Inbred BALB C , PlasmaABSTRACT
The lone oligosaccharide chain of stem bromelain was oxidized with periodic acid to generate aldehyde groups and the resulting oxidized enzyme coupled to amino-Sepharose in order to obtain an immobilized preparation with uniformly oriented enzyme. The immobilized bromelain exhibited high proteolytic activity and remarkably enhanced thermal stability as compared to soluble bromelain and that coupled to CNBr activated Sepharose.
Subject(s)
Bromelains/chemistry , Enzymes, Immobilized/chemistry , Ananas/enzymology , Bromelains/metabolism , Enzyme Stability , Enzymes, Immobilized/metabolism , Hydrogen-Ion Concentration , Kinetics , Sepharose/chemistry , Substrate Specificity , TemperatureABSTRACT
Pancreatic ribonuclease A (RNase A) has been shown to aggregate moderately and gradually at 65 degrees C. Antibodies raised against the dodecapeptide KETAAAKFERQG corresponding to the N-terminal 1-12 amino acid residues of RNase A (Npep) as well as native RNase A were effective in lowering RNase A aggregation at 65 degrees C. The antiRNase A antibodies were, however, more protective. The binding of antiNpep antibodies to the N-terminal region of RNase A may interfere with initiation of oligomerization of the enzyme and consequently its aggregation. The antiRNase A antibodies were presumably more effective in protecting RNase A against aggregation by binding to multiple epitopes of the enzyme including the N-terminal region and hence restricting the interaction of the monomers.
