First off, this drug is out of production. I believe the drug stopped production in mid-2005. The company who makes Neutersol was playing "its not fair" with the company who was mass producing the drug. I'm not sure if or when they'll start production again, however I can say drug patents only last 20 years from request, 17 from approval date. Patents aren't always held to this as the said is the max. Some drugs are known to have sooner expiration dates. The company behind Neutersol only want lots and lots of money so they'll sit on the bench until they play nice.
I've performed much research on the Neutersol. The drug is injected in to the testicles of puppies and some post adolescent dogs. The drug hinders and prevents sperm production. The dog could still have sex and get it on, but will be shooting blanks. The dog is still able to produce testosterone so he will have risk of testosterone based illnesses. I personally wouldn't care and cancer is part of life, but hey.. we have PETA nuts all around us. I'd only spueter if illness was apparent or foreseen.
The dog would still roam and have sex. Neutersol doesn't affect the dog's libido. He would be a stud shooting blanks. He would still roam, but shouldn't matter if the person is like me keeping tabs and constantly having the dog follow them around. For those concerned with a growing puppy, there aren't any reported side effects. So the premature neutering can be put to ease as the hormones are still being produced using this method versus surgery. Now, only if someone could strike out the patent because some guy wants to get rich quick.