There are actually a few separate issues to address here. First off, unless you have access to a high-grade, analytical pharmaceutical balance that weighs down to at least milligrams, and preferably down to ten microgram units, then yes, volumetric dosing using a solvent that will distribute your active compound(s) into a suspended, homogeneous solvent solution is definitely the way to go to avoid over-dosing. (Those cheap jeweler milligram scales will sometimes work in a pinch, but are generally horribly inaccurate). A quality laboratory balance scale is an essential piece of laboratory equipment. However, if you do not have access to one, volumetric dosing is the only safe option. (Depending on the level of biological activity and/or the potential toxicity of the compound, in question).
Second, I would be able to give you much better feedback if I knew the identity of the compound in question that you are working with, to even verify that it is soluble in Dimethyl sulfoxide (DMSO) to begin with. Also, it is important to consider what form said compound is in. - For example, the solubility of the compound's freebase or free acid form will vary greatly from the solubility of the same compound in the form of some kind of polar or water-soluble salt (ie. a hydrochloride, hydrobromide, sulfate, aspartate, monohydrate, etc). Also of consideration is the polarity and pH of the solvent solution once the active compound is added to the solution.
DMSO is a very low toxicity (non-toxic) polar organic solvent that is used in a very wide array of medical applications, most notably as a transdermal (through the skin) drug delivery vehicle. Also, being a protein ligand, when consumed orally, it is processed by the stomach CYP40 series cytochrome enzymes that are responsible for breaking down, metabolizing, and clearing (both renally and hepatically) it and similar structured proteins from the body. So, yes, DMSO is a very safe organic solvent, right on-par with Polyethylene Glycol (PEG) for forming medicinal solutions of active compounds that are insoluble in water, alcohol, or Polyethylene Glycol. I definitely do not think that I would ingest large volumes of it just for the hell of it, since it's high polarity would probably cause marked gastrointestinal distress. However, when used in the appropriate amount and application as a drug delivery vehicle, or for non-toxic volumetric dosing of potent active compounds, it is indeed a good choice.
-J. Gona
Psychopharmacologist
Psychotropic Treatment Specialist
Oracle Laboratories
NeuroPsych Institute