Thermosensitivity of a Topical Palmitated Formulation of Capsaicin

The study design will detect levels of patient dysesthesia in response to Capsadyn using a three-arm, group comparison. Capsadyn will be compared to an active control \[capsaicin alone (Cap)\], and to a placebo cream alone (PL). The design will use a double-blind for assignment of test article to the three arms. Both the test article administrator and patient will be blinded to test article identity. The test article will be packaged in a coded, white-label, jar with cotton swab applicator. Participants. Participants for the clinical trial will be recruited through the Carilion Clinic Dermatology Department in Roanoke, VA. In order to minimize the skin area exposed to capsaicin, test articles will be administered to about an 8 cm2 area of the volar forearm. Subject will be informed of the possibility of a transient capsaicin-induced burning sensation along with redness. Study Groups. The groups are designated Pal and Cap or PL, a placebo (PL) group. The capsaicin drugs are topical analgesics for the temporary relief of minor aches and pains of muscles and joints associated with arthritis. Pal is 0.25% palmitated capsaicin. Cap is 0.10% capsaicin alone and is an active comparator. PL is vehicle alone. Test articles will be balanced arm-to-arm by Pal/Cap, Pal/PL, Cap/PL. Pretest baseline scores will be compared to treatment scores by one-way ANOVA followed by post-hoc analyses for Pal vs PL, Pal vs Cap, and Cap vs PL. An active comparator is used since non-palmitated capsaicin (unprotected) produces heat. The sensory stimuli would break a neutral control such as vehicle alone. Zostrix at 0.1% capsaicin was used as the active comparator (Cap), a commercially-available topical capsaicin analgesic sold over-the-counter. The concentration of 0.25% capsaicin for Capsadyn (Pal), was based on the upper-limit concentration for capsaicin as specified by the FDA Tentative Final Monograph. A PL group is included since the placebo effect has to be assumed to be intrinsic to pharmaceutical intervention studies. If a placebo effect occurs that would interfere with assessment of the test article intervention, then those assessments can be evaluated with respect to the placebo group.