The emergence of DMSO as a cryopreservation agent to preserve living cells and tissue dates back to the early 1960s (24).
Dr. Stanley Jacob (an assistant professor of surgery at Oregon Health & Science University) became aware of this property
and approached the Crown Zellerbach Corporation. Crown Zellerbach was considering potential commercial applications for the
material, which was readily available from its paper–wood products businesses. Dr. Jacob went on to describe the use of DMSO
to treat a number of human ailments, including wound treatment, arthritis, and pain relief. In 1964, Crown Zellerbach received
IND status for DMSO and granted licenses to six major pharmaceutical companies in the US to develop pharmaceutical applications
for DMSO. Among these were Merck and Co., American Home products, Squibb and Sons, Schering, and the Syntex Corp. (23).
Rubin's report in 1965 that DMSO could cause lenticular changes in certain laboratory animals caused FDA to temporarily halt
clinical trials involving DMSO. FDA relaxed its ban the following year but limited research to certain untreatable conditions
(such as scleroderma). Continued research into any ocular effects that DMSO might have on humans suggests that such damage
is species dependent and is not seen in human subjects (24–26).
A groundswell of popular interest in the medicinal properties of DMSO arose in the late 1970s, and an effort to legitimize
(and legalize) the use of DMSO in medical applications was pursued. In the early 1980s, the public perception that DMSO was
being unfairly persecuted by FDA was aired in the popular press. The CBS television show "60 Minutes" presented a segment
favorable to this idea (27) and Senator Edward Kennedy (D-MA) chaired a Senate Subcommittee meeting to examine the treatment
of DMSO by FDA (22).
During the past two decades, it would seem that many concerns surrounding the safety of DMSO have largely subsided. A DMSO
product suitable for use in humans and that is manufactured according to FDA requirements is available for regulated applications,
and the products described previously are being marketed worldwide.
In addition, the case for DMSO as a panacea for an array of health problems also may be eroding. Although it is likely that
DMSO has functionality in many therapy types, it is clear that much fervor has resulted from subjective evaluation and anecdotal
experience. Many DMSO "wonder drug" claims have been evaluated in the M.D. Anderson Cancer Center's CIMER DMSO National Standard
Patient Monograph (28).
The regulatory concerns governing DMSO use in regulated applications may be similarly subsiding. It seems likely that the
public's excitement over DMSO had a significant impact on the early development of regulated pharmaceutical products that
would benefit from its inclusion. One author makes the interesting point that FDA most strictly regulated DMSO research at
the same time as the Kefauver–Harris amendment was being drafted in the US as a response to the Kevadon/thalidomide tragedy
in the mid 1960s (22).
Toxicology and health effects
The toxicology, pharmacology, and metabolic aspects of DMSO have been studied extensively (10, 29). Perhaps the most complete
summary of acute/chronic toxicity data, ecotoxicity, and environmental pathway information is available as part of the high
production volume (HPV) chemical filing on behalf of a Dimethyl Sulfoxide Manufacturing Consortium with the US Environmental
Protection Agency (30). Based on the wealth of information available, it is a fair statement that DMSO possesses a low degree
of toxicity to humans via oral and parenteral routes. DMSO is not carcinogenic and is not a reproductive toxin. It is worthwhile
to point out that DMSO is used as the background solvent in biological assays of mutigenicity (Ames test). As such, it is
widely recognized that DMSO is not a mutagen. Table V provides a thumbnail overview of toxicological indicators for DMSO.
Table V: Toxicological overview of dimethyl sulfoxide (10).