Preparation and Evaluation of a Modified Mohs Paste Mixed with Zinc Oxide 10% Topical Oil-Based Ointment

The skin fixative used in Mohs chemosurgery contains zinc chloride and is referred to as Mohs paste (MP). However, MP shows a remarkable change in rheological characteristics after its preparation.

To prepare an MP with stable rheological characteristics, we prepared a modified MP (mMP) using zinc oxide 10% single ointment (Zn_{_ointment}), which is an oil-based ointment.

We evaluated mMP by determining its rheological characteristics, depth of tissue fixation, and observation of the tissue surface after treatment.

The viscosity of mMP increased after three months. However, the treatment-dependent viscosity of mMP could be obtained by mixing with glycerin. The viscosity and spreadability of mMP_{_3mth}, which was three months after preparation, were 1992.0 ± 376.5 Pa·s and 2.1 ± 0.1 cm, respectively. In contrast, the viscosity and spreadability of MP mixed with glycerin were 436.9 ± 0.0 Pa·s and 2.8 ± 0.0 cm, respectively. The fixed invasion depth of MP was significantly higher than that of mMP (p < 0.05).

This study of a mixture of MP and Zn_{_ointment} showed that the viscosity of mMP could be adjusted with glycerin. Also, the tissue fixation of mMP progressed slowly compared with that of MP. This finding suggests that mMP is effective and safe for Mohs treatment.