2007-03-21 05:37:44 · 4 answers · asked by ssnanni 1 in Science & Mathematics ➔ Medicine
For a tablet, there are a few basic methods for providing a controlled release dose. Polymers with different properties such as permeability and pH-dependent solubility are chosen based on the desired release profile for the drug. These polymers are used either 1) in the coating of the tablet or 2) in the core of the tablet. In either method, the polymer controls the amount of water reaching the drug and allowing only a small part of the drug to release in the body over an extended period of time. Another type of controlled-release tablet, an osmotic tablet, involves the use of an insoluble coating and a laser drill. The drill is used to make small holes in the tablet's coating, thus controlling the amount of water coming in and drug going out.
Another popular route for preparing controlled-release medications is using the capsule dosage form. Pellets in the capsule can be prepared by extrusion and spheronization, or a "base" pellet (sugar spheres, cellulose spheres) can be layered with the drug and polymer using the Wurster coating method.
None of these methods is significantly better than another, the dosage form depends mostly on the drug's dosage requirements, desired release profile, and compatibility with manufacturing processes and excipients.
2007-03-21 10:22:50 · answer #1 · answered by pharmgrl 3 · 0⤊ 0⤋
The other two people are right. Usually in a capsule, you see multicolored little beads. Among these beads, there are two or three different types of coatings--some that release the drug right away, some that take longer, and some that take even longer. The result is that the drug is released steadily throughout the dosage period (day, 12 hours, etc).
The same thing happens in a pill, except the different little beads are not as obvious, as they are all pressed together.
With extended-release insulin (like NPH or lantus), there are little pieces of protein that act like the beads in a pill, and allow the insulin to be released at a steady rate into the fatty tissue where it was injected.
2007-03-21 10:05:37 · answer #2 · answered by sarcastro1976 5 · 0⤊ 0⤋
The coating around the pill does not dissolve and acts as a membrane allowing only a portion of the drug to pass through.
2007-03-21 05:47:32 · answer #3 · answered by n0tsan3 3 · 0⤊ 0⤋
The coating.
2007-03-21 05:40:11 · answer #4 · answered by Timothy C 5 · 0⤊ 0⤋