What do the G or V of Penicillin (as in Penicillin G or V) means? Where does it come from?

I've been looking for that answer in several articles on the net, but none of them seems to tell why it was named as such.
i think i remember seeing somewhere that it was because several penicillin tryouts where made at a given moment, and a few ones, naming G, V, F or X worked (A, B, C, etc didnt work i think).but, i dont know if thats true. is there a website i can find to look for an answer?? thanks in advance
Answers:
Penicillin V is the ORAL form of Penicillin and is indicated for minor infections only. Because of its relatively poor bioavailability, the need for dosing four times a day and its narrow antibacterial spectrum, the antibiotic Amoxicillin is used instead.On the other hand, Penicillin G is the IV form of Penicillin. Penicillin G is the drug of choice for infections caused by Streptococci, Meningococci, Enterococci, Penicillin-susceptible pneumococci, non beta-lactamase producing staphylococci, Treponema pallidum, Bacillus anthracis, Clostridium species, Actinomyces and other gram positive rods and non beta-lactamase producing gram negative anaerobic organisms. Penicillin G's effective doses usually range between 4 to 24 million units per day and administered IV (intravenously) in 4 to 6 divided doses.Other forms of Penicillin G are Benzathine Penicillin and Procaine Penicillin. Benzathine Penicillin is satisfactory for the treatment of beta-hemolytic streptococcal pharyngitis (1.2 million units intramuscularly administered). Procaine Penicillin G is rarely used at present due to many strains that are resistant to it.i hope this helped you!

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u're qiut right..check it out.
http://www.yarchive.net/med/penicillin.h.where does it come from (look in the history part)
http://dictionary.laborlawtalk.com/penic.Benzylpenicillin, commonly known as penicillin G, is the gold standard penicillin. Penicillin G is typically given by a parenteral route of administration because it is unstable to the hydrochloric acid of the stomach.
Phenoxymethylpenicillin, commonly known as penicillin V, is the orally-active form of penicillin. It is less active than benzylpenicillin, however, and is only appropriate in conditions where high tissue concentrations are not required.

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The naming is for the same reason that we have "Preparation H". I can't help but feel sorry for the poor bastards that got Preparations A through G - I hoped that they survived. SQC------------------------------.
SQC: Sitting Quietly Chuckling. I was not LOL or ROTFL. I was simply SQC

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