Hi again
I only have personal experience with Oxycodone, Oxymorphone, Morphine and Fentanyl. I always found Oxycodone Instant Relief to be great for breakthrough pain ( something like Roxicodone, I use Oxynorm IR Liquid here in the UK, 5mg per 5ml liquid, and it always worked brilliantly until my tolerance was through the roof and I was taking 400-600mg per day... But that's another story LOL ). But seeing as you are taking Dilaudid for BT pain, and it works great, then stay with it. Don't try fix something that isn't broken
As for your ER meds... As I described above, I would avoid Opana purely for the reason of the low Oral BA, as stated, in reality its only people who use other methods of administration that get the full benefit out of it, and no, you don't want to start abusing your meds and trying different ways for it to work better, I promise you this when I say it, that it will only come back and bite you in the ass.
As of now I am no longer on Oxycodone, I am on Fentanyl Duragesic Patches, the 100mcg/hr ones. When used transdermally as intended, these patches have a 100% BA, so you get all the medication that is going into your bloodstream. I have been on opiates for over 3 years following severe medical problems, and if I'm honest with myself, I find the patches to be great for 'round the clock' pain maintenance, as it is a controlled amount of opiate being absorbed every hour, continuously ( say 100mcg/hr, so 2.4mg per 24hr period ). If you were to speak with your Pain Management Dr and have the Fentanyl vs Oxycontin conversation, and see if he would be willing to let you 'test it out', you may find that it will work brilliantly for your pain, and along with your Dilaudid for BT pain, I honestly think you will have all bases covered. Fentanyl works great for my pain ( abdominal, lower back ) and along with an IR med it covers all angles and lets me live as near a normal life as possible.
From previous calculations I have made ( please see my Fentanyl Withdrawal Thread for proof of this if you wish ):
100mcg of Fentanyl IV = 100mcg of Fentanyl Transdermal = 15mg of Oxycodone Oral.
So, you take 120mg of Oxycontin per day, which would mean you would need to have approx 800mcg of Fentanyl per day for it to be on a 'dose for dose' ratio.
800mcg/24hrs in a day = ~34mcg/hr of Transdermal Fentanyl needed for equivalent dosage of 120mg Oxycontin per day.
They make 12.5mcg, 25mcg, 50 mcg, 75mcg and 100mcg/hr patches. I would
suggest a 25mcg/hr patch and a 12.5mcg/hr patch to try it out, so 37.5mcg/hr, if you wish to try Fentanyl ofcourse - This is slightly more than the 60mg of Oxycontin twice per day, but you have to take approximations into account, so it would be nearly equal opiate-wise to what you are currently receiving. I'm sure if you did in fact try this great med out, it would do a great deal for your pain combined with your Dilaudid IR.
Sorry for the long post, but I like to try explain these things in terms everyone can understand who are not experienced in opiates and conversions etc, so I hope this helped.
As for your question on plastic in Oxycontin and the health aspects of it, yes they contain polymers in them which they have put into the formula to try stop people from abusing them. You are not the first person to complain about stomach problems as a result of ingestion I'm afraid

Sorry, can't help you with that, though it might just give you more of a reason to want to switch meds.
**** Disclaimer - I am not a Doctor nor do I claim to be one, nor am I any sort of Healthcare Professional, nor is anything written here intended as advice - it is purely my own personal experience, and research. Please discuss anything you wish to do/change with your Healthcare Professional first ****