MIAMI BEACH – A 4% topical lidocaine cream with a nanotechnology-based vehicle in development provided superior pain relief before facial filler injections, compared with the most commonly-used topical anesthetic cream, according to patient and physician ratings in two split-face studies.
"This really has potential as the next topical anesthetic," Dr. Glynis Ablon said at the South Beach Symposium.
Dr. Glynis Ablon
Although most dermatologists and pediatricians apply topical anesthetic products (such as commonly used LMX4 cream) approximately 20 minutes before needle-based procedures, the efficacy of NTL4 (Cutiecaine Cream) was seen in as little as 5 minutes, Dr. Ablon said.
NTL4 is formulated with a novel nanoparticle vehicle (INParT Drug Delivery System) that passively transports active compounds deeper into the skin. "It's a great new way to deliver lidocaine into the skin faster," said Dr. Ablon, a dermatologist in private practice in Manhattan Beach, Calif. The technology is also being assessed for new topical hyaluronic acid and topical botulinum toxins.
Dr. Ablon and her colleague Dr. Mark Nestor, who is in private practice in Aventura, Fla., conducted an initial study of 30 patients with NTL4 applied to one side of their face and over-the-counter LMX4 to the contralateral side, followed by a 20-second massage. After 20 minutes, Restylane was injected for facial rejuvenation. Participants and blinded raters assessed pain relief.
"The study was started to see if we could get that [numbing effect] in 20 minutes, and obviously faster numbing times could be a great thing for dermatologists as well as pediatricians," Dr. Ablon said.
Twenty patients (67%) reported minimal or no pain when injected on the NTL4 side of their face, compared with 12 patients (40%) who reported minimal or no pain on the LMX4 treated side. "Overall, patients significantly preferred treatment with NTL4 over LMX4," she said. The mean visual analog score (VAS) for pain was 1.99 in the NTL4 group vs. 3.08 in the LMX4 group immediately after injection; 0.21 vs. 0.74 at 1 hour; and 0.07 and 0.31 at 3 hours postinjection.
Blinded investigators also rated significantly less pain with NTL4, Dr. Ablon said.
Adverse events were minor and included some tenderness and bruising. Also, there was "some edema we believe was due to the actual injection of the Restylane."
In a second study, Dr. Ablon and Dr. Nestor assessed 5-, 10-, and 15-minute application times. The 20 participants had a 30-second massage of the topical anesthetic and subsequent Restylane injections of their nasolabial folds.
Sixteen patients (80%) treated with NTL4 reported minimal or no pain, compared with one patient (5%) treated with LMX4, according to pooled data for subjective pain ratings after 5-, 10-, and 15-minute application times.
"We did show that they had significantly less pain on injection with the NTL4 at the 5- and 15-minute incubation, with a trend favoring it at 10 minutes," Dr. Ablon said.
Mean VAS pain scores were significantly lower for the NTL4 group when injected 5 minutes after application: 1.72 for NTL4 vs. 4.20 for LMX4. Patients also reported a significant difference in pain when injected 15 minutes after injection: 1.92 with NTL4 vs. 4.67 with LMX4. There was a nonsignificant trend favoring lower VAS scores with NTL4 after a 10-minute application time(1.08 for NTL4 and 3.00 for LMX4).
All patients preferred the NTL4 side versus the LMX4 side for pain relief. Blinded investigators’ evaluation of pain was also statistically significant in favor of the NTL4, Dr. Ablon said.
Adverse events were minor in this study as well. "We did have one patient with edema that we think might have been an actual reaction to lidocaine," she noted.
"There is a lot going on with nanotechnology, and [it] is here to stay," Dr. Ablon said. This technology can be found in suntan lotions, age-defying makeup, and even toothpaste that coats damaged enamel.
The studies were funded through an unrestricted educational grant from Innovatech. Dr. Ablon and Dr. Nestor are consultants and investigators for Transdermal Corp.