Biomedical Engineering Reference
In-Depth Information
values reported occasionally. A nonlinear correlation between the verapamil dose
administered and verapamil plasma levels does exist.
The dose-ranging population pharmacokinetics of an osmotic controlled release
verapamil has been studied in healthy subjects and patients with angina or hyper-
tension. Immediate release verapamil has an approximate fourfold greater apparent
clearance than controlled release verapamil in both healthy volunteers and patients.
Waxy microparticles prepared by the ultrasonic spray congealing technique are
promising solvent-free devices for controlling the release of verapamil in vivo.
Methods of Administration of Proteins and Peptides
Several of the current drugs are proteins or peptides and many more in this category
are in development. Various possible routes for administration of proteins and pep-
tides are:
•
Parenteral
•
Transdermal
•
Inhalation
•
Transnasal
•
Oral
•
Rectal
•
Implants
•
Cell and gene therapies
•
Use of special formulations
Injection still remains the most common method for administration of proteins
and peptides. Efforts are being made to use needle-free or painless injections and
also to improve the controlled delivery by parenteral route. The ideal delivery sys-
tem for proteins and peptides should have the following characteristics:
•
It should be patient friendly
•
Noninvasive
•
It should provide good stability of the product
•
Bioavailability should be high
•
Dosing and absorption rates should be reproducible
•
Should be cost-effective
Delivery of Peptides by Subcutaneous Injection
Subcutaneous still remains predictable and controllable route of delivery for
peptides and macromolecules. However, there is need for greater convenience
and lower cost for prolonged and repeated delivery. An example of refinement of
subcutaneous delivery is MEDIPAD (Elan Pharmaceutical Technologies), which is
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