ABSTRACT
Many different agents, including mineral oil and silicone, have the capacity to act as immunological adjuvants, i.e., they can contribute to the activation of the immune system. Some adjuvants, including mineral oil, are known to induce arthritis in certain strains of rats after intradermal injection or percutaneous application. The aim of this study was to determine if common commercial cosmetic products containing mineral oil could induce arthritis in the highly susceptible DA (Dark Agouti) rat. Intradermal injection of five out of eight assayed cosmetic products without further additives resulted in arthritis with synovitis. One of the products induced a very aggressive arthritis, which had declined after 5-9 weeks. When this product was also assayed for arthritogenicity upon percutaneous administration, it induced a mild and transient arthritis in 5 out of 10 DA rats, whereas control animals showed no clinical signs of joint involvement. No arthritic reaction was seen in rats after peroral feeding with the most arthritogenic product or by intravaginal application of Freund's adjuvants. Silicone gel implants in DA rats did not cause arthritis. We conclude that mineral oils included in common commercially available products retain their adjuvant properties and are arthritogenic in the presently investigated arthritis-prone rat strain. There is yet no evidence that mineral oils present in cosmetics may contribute to arthritis in humans, but we suggest that this question should be subject to further investigation.
Subject(s)
Arthritis, Experimental/chemically induced , Cosmetics/toxicity , Administration, Oral , Animals , Arthritis, Experimental/immunology , Arthritis, Experimental/pathology , Autoantibodies/biosynthesis , Cosmetics/administration & dosage , Drug Implants , Female , Gels , Injections, Intradermal , Injections, Subcutaneous , Irritants/toxicity , Joints/pathology , Male , Mineral Oil/administration & dosage , Mineral Oil/toxicity , Ointment Bases/administration & dosage , Ointment Bases/toxicity , Rats , Rats, Inbred Lew , Rats, Inbred Strains , Silicone Gels/toxicityABSTRACT
Conventional adhesive ointments cause irritation to the mucous membranes. Therefore, a novel mucosal adhesive ointment based partly on neutralized polymethacrylic acid methyl ester was formulated. The flow curves of the ointment vehicle showed pseudoplastic properties. The rheological behavior as well as the adhesion on the mucosal membrane could be varied by the type and concentration of the polymer used and the base used for neutralization. During clinical studies, the ointment vehicle as well as a tretinoin (vitamin A acid) preparation for the treatment of lichen planus did not cause any local irritation or systemic side effects. Both vehicle and preparation were found to be pleasant for the patients to use. The new system of the mucosal adhesive ointment is not limited to the incorporation of tretinoin as the active agent; combined with other drugs the system could be applied to all types of mucosal membranes.
