time release methylphenidate pills

[Bb0yJeStEr]

i dunno if this is even the right website to be asking this question... inside a time release methylphenidate (ritalin) pill, there is usually half of it white and half of it brown, and a little bit of pink at the end. these are not just coating colors- they are actual colored substances. my question tho is what is the brown colored shit?? i know for a fact the white shit is methylphenidate and i am kinda convinced the pink is too, but what is the brown part made up of? is it just filler??

 

[fairnymph]

from www.rxlist.com:

CONCERTA™ uses osmotic pressure to deliver methylphenidate HCl at a controlled rate. The system, which resembles a conventional tablet in appearance, comprises an osmotically active trilayer core surrounded by a semipermeable membrane with an immediate-release drug overcoat. The trilayer core is composed of two drug layers containing the drug and excipients, and a push layer containing osmotically active components. There is a precision-laser drilled orifice on the drug-layer end of the tablet. In an aqueous environment, such as the gastrointestinal tract, the drug overcoat dissolves within one hour, providing an initial dose of methylphenidate. Water permeates through the membrane into the tablet core. As the osmotically active polymer excipients expand, methylphenidate is released through the orifice. The membrane controls the rate at which water enters the tablet core, which in turn controls drug delivery. The biologically inert components of the tablet remain intact during gastrointestinal transit and are eliminated in the stool as a tablet shell along with insoluble core components.