Jan. 31, 2008  5  US 2008/0026974 Al  [0041]  Per the preferred embodiments, lactic acid,  pKa  of  3.86, and monoethanolamine, pK$_{6 }$ of 4.56, the pH at the  equivalence point should be 6.65. This is experimentally  verified in FIG.  2.  Because of the spontaneity of the reaction  the ratio of acid to base can be in any proportion, although  near equivalence is most desired.  [0042]  The resulting solution varies slightly in appearance  depending on the reaction conditions.  If the reaction is  carried out slowly and the heat is allowed to dissipate the  solution can be colorless, but if the reaction is done quickly  and heat builds up, then the solution will tum to an amber  color because of the oxidation of monoethanolamine. The  solution also has a slightly honey-like odor. One inherent  observation is an increase in the viscosity of the solution.  Starting from two water thin liquids, the final solution has a  viscosity of about 1500 to 3000 centipoise.  [0043]  Although there are numerous antimicrobial agents,  the most preferred embodiment contains halogenated diphe› nylether. Most specifically, the use of pcmx and/or triclosan  is most desired. These two compounds, and most specifi› cally triclosan, interact with the amine salt to produce a more  efficacious hand wash. The hypothesis governing this trend  is described as charge interaction between the negatively  charged triclosan substitutents, chlorines and the hydroxyl  group, and the positive charge found on the amine group.  Triclosan has a  pKa  value of 7 .4, so, at the desired pH of the  hand wash, the triclosan will be disassociated and have a  negative charge. The positive charge on the amine is  attracted to the negative charge on the triclosan and, thus, the  triclosan is chelated and prevented from precipitating.  [0044]  The antimicrobial properties of the hand wash  containing an amine salt are improved compared to hand  washes without. This improvement is seen both in the broad  spectrum inhibition and the quick inhibition. A log reduction  of 2 on hard to kill organisms, specifically  Staphylococcus  aureus  (MRSA) ( ATCC#335 91) at 30 second exposure time,  is desired and, as such, this hand wash provides greater than  2 log reduction of both the Gram positive  Staphylococcus  aureus  (MRSA) (ATCC#33591) and  Shigella dysenteriae  (ATCC#l3313).  [0045]  While making soap through a saponification reac› tion of a primary nitrogenous base with a primary fatty acid,  the addition of excess base was examined. Because the high  pH resulting from excess base would be irritating and  detrimental to the skin care properties of the hand wash, the  excess base was neutralized with a second water soluble  acid. For a first control (Control 1), a hand wash made  without excess base was tested along side the hand wash  containing excess base neutralized with the second acid. A  second control (Control 2) excess base is present, but is not  subsequently neutralized with the second acid. The hand  washes included antimicrobial agent, namely triclosan. The  base was monoethanolamine. The first acid was !auric acid,  and the second was lactic acid.  [0046]  The triclosan was dissolved in dipropylene glycol,  to make an "active premix." The monoethanolamine was  added to the water and then the !auric acid was added. After  allowing the saponification process to complete, lactic acid  was added to neutralize the excess base, and was added until  the solution was brought to a pH of 9 .25. The active premix  was then added to the solution to create the antimicrobial  hand wash. The ingredient amounts were as follows:  A log reduction test was performed for each formulation.  The samples were tested by placing a loopful (approx 10  microliters) of the formulation into a microbial broth  (Staph.  Aureus  ATCC#6538) for 15 seconds. A sample was then  taken from the broth and plated. The bacteria was grown and  then counted resulting in a quantitative reduction value, as  shown below.  There is a dramatic increase in the log reduction for the  antimicrobial hand wash employing excess base subse› quently neutralized with a second acid. This suggests that  the neutralized excess base improves the antimicrobial prop› erties of the hand wash.  [0047]  Because there is a boost in the efficacy of the  product due to the use of excess primary nitrogenous base  and a secondary neutralizing acid, alternate bases were  tested. The focus was to find suitable weaker bases that  might be used, because weaker bases should further reduce  the degree of skin irritation experienced when using a  resultant antimicrobial hand wash. Samples were made  using the same procedure as in Example 1, but with alternate  bases. Because the bases had different molecular masses, the  percentage used in each sample was different. This was done  in order to ensure that the same number of moles were  present in each sample, thus allowing for the same concen› tration of amine salt in the final hand wash. As mentioned the  same formulation was used as in Example 1, but with the  base, monoethanolamine, replaced with the following:  Triethanolarnine  Arninomethylpropanol  (AMP-95)  Tetrahydroxypropyl  ethylenediamine  (Neutral TE)  Alternate Bases  9.355 g  5.525 g  10.29 g  Equistar, USA  ANGUS Chemical, USA  BASF, USA  Control 1:  Excess Base:  Control 2:  log reduction 0.6  log reduction 4.0  log reduction 1.3  Excess Base:  Control 1  Control 2:  Water  q.s. to 100 g  q.s. to 100 g  q.s. to 100 g  Laurie Acid  5 g  5 g  5 g  Monoethanolarnine  3.833 g  1.7  g  3.833 g  Lactic Acid  q.s. to pH 9.25  NIA  NIA  Dipropylene Glycol  3 g  3 g  3 g  Triclosan  0.3 g  0.3 g  0.3 g  pH: 9.22  pH: 9.21  pH: 10.30  Example 2  EXPERIMENTAL  Example 1 