Drug Delivery-not a visit from your pharmacist
Drug delivery refers to the area of altering the way drugs are released in the body. In many (but not all) cases, this refers to the way the active ingredient is “packaged”, and typically doesn’t involve changing the drug’s molecular structure. Drug delivery encompasses:
Timing-changing the amount of time it takes for a drug to be consumed. Let’s say there’s a great drug for migraines, but it’s eliminated from the body in two hours. Taking a pill every two hours is going to be very inconvenient. Can we change it to 12 or 24 hours?
Route-changing the way a drug can be adminstered. Can we make an oral version of a drug that’s currently given IV only?
Solubility-A great example of this is the cancer drug paclitaxel (Taxol). It has good antitumor activity, but it’s highly insoluble in aqueous solvent. How can we deliver it to the (aqueous) human environment?
Targeting-Can the drug only target the area of disease, (e.g., cancer cells), and leave healthy cells unaffected?
The approaches used in drug delivery and accompanying details are too numerous to discuss in a single blog post, but I’ll discuss a few. One strategy is to encase the active ingredient in a biocompatible material. Depending on the material’s properties, it may release the drug either through diffusion or degradation. This can be used to address solubility, route, and timing issues.
Another strategy involves designing a delivery device. Subcutaneous implants and skin patches fall into this category.
Targeting can be achieved through passive means such as a material that degrades at a specific pH, or it can be done by active means. Active targeting is typically accomplished by having a compound that binds to a specific cell receptor.
The type of work I do involves a class of polymers called hydrogels, which I’ll discuss more in the next post.