Oral Modified-Release Dosage Forms

1. Use barrier coatings to control access of biological fluids to the drug.
2. Control diffusion rates from dosage forms
3. Chem. rxn / interaction between drug (or barrier) and site specific biologic fluid

Drug can put on beads, pellets or granules usu. by spry method.
Drug can be incorporated into a granule
Pellets, beads/granules are coated in ways to change dissolution rate

Beads have coats of different compositions to control realease

or same coating with different thickness
(ex. dosing unit of 100 beads made of 3-4 release groups- usu. 1 is immediate release)

Same as Coated beads, granules, and microspheres but SMALL TABLETS are used with various release rates.

These are combined (usu. in a hard gelatin capsule) to produce the dosage unit.

Formation of a thin coating or wall around a microscopic particle of drug.

1. Coating material is dissolved in water.
2. Drug to be coated is added and stirred.
3. Surface active agent is added.

Concentrates the coating material into droplets.
2. Lower the surface tension so coating material (of drug) is a continuous tight film.

1. Changing ratio or core to wall

2. Changing the polymer used as the coating
3. Different microencapsulation techniques.

Both - drug is combined and made into granules with an excipient material that slowly erodes in body fluids and releases the drug for absroption.