Something as simple as a bit of salt may help more of the arginine pass through the skin:
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Other Means of Effecting or Improving Absorption A variety of means for effecting or improving absorption of the active agent can be envisioned, which are provided in the following several embodiments. One principle behind the absorption of a highly charged molecule such as L-arginine into tissue is to either create a biophysically hostile environment in the delivery vehicle such that L-arginine would prefer to be in tissue, or in an another embodiment is to package L-arginine in such a way that it is carried into tissue or neutralize its charge by derivitization or forming a neutral salt. Examples of biophysically hostile environments, include but are not limited to; high ionic strength by the addition of ionic salts such as sodium chloride, magnesium chloride or choline chloride; high or low pH by adding pharmaceutically acceptable acids or bases; and highly hydrophobic environments by decreasing water content and increasing lipid, oil and/or wax content.
Examples of the other embodiment of packaging which would be carried into tissue includes liposomes or emulsions of collagen, collagen peptides or other components of skin or basement membrane. Examples of neutralization of charge include delivery of the active agent in the form or an ester or salt such as arginine glutamate which is electronically neutral. In each case of creating a hostile biophysical environment for the active agent, the agent was added to an appropriate preparation.
In the case of creating a high ionic strength ions such as but not limited to sodium chloride, potassium chloride, choline chloride, magnesium chloride, lithium chloride, alone or in combination were added in high concentration. An example of a high concentration of high strength ions are sodium chloride (0.25% to 25%), choline chloride (0.25% to 25%) and magnesium chloride (0.25% to 25%) alone or. in combination.
Other highly charged molecules such as polylysine, polyglutamine, polyaspartate or copolymers of such charged amino acids may be used to create the hostile biophysical environment. Alternatively a hostile biophysical environment may be created by placing the highly charged L-arginine in an hydrophobic, oily environment such as in an oil-based cream containing little or no water.
Absorption may further be aided in another embodiment, by combining the use of hostile biophysical environments with the use of penetrating agents such as oleoresin capsicum or its constituents or molecules containing heterocyclic rings to which are attached hydrocarbon chains.