Welcome back to Baby Breakerdom! This week's quest to find budding Rule Breakers reveals pain sufferers mainlining Tylenol, and a new concept that could shake the very foundations of the credit industry.

First up this week is Prosper Marketplace, which seeks to be the eBay (NASDAQ:EBAY) of loans. It's a very descriptive moniker: Prosper, founded by the brain trust behind E-Loan, seeks to bring together lenders and borrowers with no bank in the middle. Unbridled capitalism at its finest. As I write today, the prospective borrowers include a Yale Law student, a 29-year-old retail professional, and a young family seeking to escape the clutches of credit card debt.

Even more interesting, however, is how Prosper will manage the loans as they occur. Every loan on the site is bid on auction-style, a la eBay. When bidding is concluded, Prosper combines all the lowest-interest rate bids into one complete loan, then handles all the administration, according to VentureWire.

I find the idea tantalizing -- and frightening. (Seriously, how do you really know whom you're lending to?) Rule Breaking investors remain undaunted, however. Prosper closed a $12 million second round of financing in January. Participants included Fidelity Ventures, which led the round; existing shareholders Accel Partners and Benchmark Capital; and the Omidyar Network, which is the investing arm for eBay founder Pierre Omidyar.

Next up is Cadence Pharmaceuticals. According to VentureWire, it's working to introduce a pain-relief alternative for patients who previously used Cox-2 inhibitors such as Merck's (NYSE:MRK) Vioxx and Pfizer's (NYSE:PFE) Bextra.

But the method, not the drug, is the most interesting part of this story. Cadence used a recent $53.8 million funding round, led by Frazier, to purchase North American rights to what's called IV acetaminophen from Bristol-Myers Squibb (NYSE:BMY). That probably sounds familiar, since acetaminophen is the primary ingredient in Tylenol and similar pain relievers. In effect, IV acetaminophen is Tylenol through a tube.

Phase 3 trials will begin soon, according to VentureWire. If the drug passes as expected -- it is already available in Europe -- it could become the treatment of choice for patients who can't keep down a pill, or who have adverse reactions to opiates such as morphine. Either way, it seems like a Rule Breaking innovation with a multimillion-dollar future.

Sadly, there were no Baby Breaker public offerings this week, which means it's time to say goodbye. See you back here next Friday, when we continue the quest to find the next ultimate growth stock.

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eBay is a Motley Fool Stock Advisor selection. Pfizer is a Motley Fool Inside Value picks. Merck is part of the Motley Fool Income Investor portfolio.

Fool contributor Tim Beyers can appreciate Prosper users who are struggling with credit card debt. He's been there himself. Tim didn't own shares in any of the companies mentioned in this story at the time of publication. You can find out what is in his portfolio by checking Tim's Fool profile . The Motley Fool has an ironclad disclosure policy .