The study was designed to demonstrate the ability of TPM to deliver lidocaine (5%) to a targeted local site after a single topical application, while restricting systemic exposure. Lidocaine concentrations were measured in the skin at the site of application, as well as in the underlying muscle and tissue. The studies were performed in parallel using a leading commercial form of lidocaine, Xylocaine 5%, to assess the relative efficacy of the TPM/Lidocaine formulation.
Phosphagenics’s TPM/Lidocaine increased, by a statistically significant margin (p is less than or equal to 0.001), the amount of lidocaine delivered to the skin at the site of application as compared to Xylocaine 5%. The lidocaine concentration in skin was approximately 900% higher 5 hours after topical application of TPM/Lidocaine, compared to Xylocaine alone. In addition, TPM/Lidocaine was able to increase the depth of lidocaine penetration. A significant (p < 0.001) increase of approximately 500% in lidocaine was detected in the thigh muscle of animals treated with TPM/Lidocaine over Xylocaine alone. Importantly, the increases in lidocaine delivery to both skin and muscle did not lead to a significant increase in systemic exposure. The average plasma lidocaine concentration peaked one hour after the topical application for both TPM/Lidocaine and Xylocaine. The differences in plasma concentration were not statistically significant. This is particularly impressive given the magnitude of the differences in the lidocaine concentrations in both skin and muscle. These results show that TPM has the potential to be used as a targeted, localized delivery system, capable of increased delivery of therapeutic levels of lidocaine, and very likely other products, to targeted areas while minimising exposure to the rest of the body. A Phase I human clinical trial is scheduled to commence in the third quarter of 2008.