Resumen

Objectives: Assess microscopic depth of injury and neocollagen production with use of deep chemical peels (Hetter's very heavy formula containing 1.6% croton oil in 35% phenol and pure croton oil) via drug-tattooing technique versus topical application alone using cotton-tipped applicator Introduction: Deep chemical peels can consist of a mixture of phenol, croton oil, water, and emulsifying agent (Septisol [SEP]). Baker-Gordon’s (2.1% croton oil/49.3% phenol) and Hetter’s standardized formulas (1.6% croton oil/35% phenol) are some examples of deep chemical peels. Depth of injury of deep chemical peels is often variable and difficult to assess, especially when applying the chemical agents using a simple cotton tipped applicator. Materials / method: Using a porcine in vivo model, dermal delivery of pure croton oil and Hetter’s formula was performed with drug-tattooing technique using Cheyenne Hawk Pen 23-Magnum SE set at 120 Hz with 1.5 mm needle depth. Punch biopsies were obtained (hematoxylin and eosin) 24 hours later to assess microscopic depth of injury based on necrosis/neutrophilic band (measured in micrometers and evaluated via black India tattoo ink) and 21 days later to assess neocollagen production (Herovici collagen stain). Three test sites were used for Hetter’s formula, pure croton oil, and black India tattoo ink (control). Results: Deeper dermal injury was measured with the pure croton oil tattooing compared to tattooing of Hetter’s formula. Topical application of pure croton oil did not cause evident dermal injury. Conclusion: Drug-tattooing can be a promising method of drug delivery (particularly with non-phenol containing chemical peels, like pure croton oil) and is associated with deeper dermal penetration and neocollagenesis. Future studies using human subjects are needed to assess depth of penetration of chemical peel formulas for a variety of clinical indications, including scarring, dyspigmentation, sun damage, and wrinkles. More studies also need to be done with more dilute croton oil solution to further assess depth of injury and neocollagenesis with varying concentrations of chemical formulas.