Does naloxone serve its puropse in Suboxone?

[Mandark]

The rationale behind introducing a combined formulation of buprenorphine and naloxone in Suboxone was that naloxone given intravenously (or intranasally) would block the effects of buprenorphine, which would deter users from injecting Suboxone. However, there is a lot of annecdotal evidence (from both Erowid and BL) that Suboxone can be successfully abused by IV route. The explanation often given for this is that buprenorphine has higher affinity to opioid receptors than naloxone. One opinion I've seen was that naloxone was added to the pill only for patent reasons.

As this appears to be the consensus, I'd like to be able to support it with peer-reviewed literature. However, I can't really find many supporting studies on PubMed. So far I've found this:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4079473/ ("Self-administration of Intravenous Buprenorphine and the Buprenorphine/Naloxone Combination by Recently Detoxified Heroin Abusers")
http://www.ncbi.nlm.nih.gov/pubmed/24793093 ("The reinforcing and subjective effects of intravenous and intranasal buprenorphine in heroin users")

But on the other hand this:
http://www.ncbi.nlm.nih.gov/pubmed/25060839 ("Abuse potential of intranasal buprenorphine versus buprenorphine/naloxone in buprenorphine-maintained heroin users")
http://www.ncbi.nlm.nih.gov/pubmed/20403021 ("Abuse liability of intravenous buprenorphine/naloxone and buprenorphine alone in buprenorphine-maintained intravenous heroin abusers")
http://www.ncbi.nlm.nih.gov/pubmed/2453895 ("Buprenorphine and naloxone alone and in combination in opioid-dependent humans")

I'm not that good at systematically searching for publications (I tend to randomly stumble upon ones that interetest me), so I'm sure I've missed some relevant ones. That's why I would like to ask you for your help in establishing whether there is published evidence that naloxone is ineffective in preventing recreational buprenorphine (a)buse. Any additional studies or your thoughts on the issue are welcome.

 

[serotonin2A]

The relative affinities of buprenorphine and naloxone isn't really the issue. An opiate with extremely high affinity, carfentanil (Kd = 8.9pM!!! [1] or 80 pM [2]), is used to radiolabel mu receptors for binding studies [2]. If low affinity ligands could not displace higher affinity ligands then there would be no point to performing binding studies with carfentanil, but obviously that is not the case. In fact, binding studies are often performed with high affinity radioligands to reduce nonspecific binding.

Buprenorphine does have high affinity, but the real issue is that it has a very slow dissociation "off rate" from the receptor, so it is difficult for other ligands to displace it. Once buprenorphine binds to the receptor, it stays bound for a long time, and it can't be displaced by another drug until after it dissociates from the receptor.

[1] http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA187637
[2] http://www.sciencedirect.com/science/article/pii/0014299989905827#