Background and Objectives: Tissue engineering skin is a three-dimensional skin substitute
cultured in the gas-liquid interface using the immortalized keratinocytes (HaCaT cells). In this study,
the preliminary metabolism of betamethasone dipropionate by tissue engineering skin was studied and
the pharmacokinetics methodology was established using betamethasone dipropionate gel as the target
Methods: The betamethasone dipropionate gel was applied on the tissue engineering skin after the skin
was cultured. Then the medium (receiving liquid) and skin were taken on 0.25, 0.75, 1.75, 3, 5, 8, 12,
24, 36, 48 h time points. The betamethasone concentration in the medium and skin was determinated by
the LC-MS method. Chromatographic analysis was conducted using isocratic elution on a C18 column
(150 mm × 2.0 mm, 5 μm) in mobile phase consisting of methanol and water (70 : 30, v/v). The mobile
phase was pumped at a flow rate of 0.2 mL/min.
Results: This method exhibited linearity within the concentration range of 0. 1 to 50 μg /mL of betamethasone.
The LLOQ was 0. 1 μg /mL. The intra- and inter-day precisions of betamethasone in the
blank medium were all less than 10.69 % (RSD, %), while in the blank, skin homogenates were all less
than 13.96 % (RSD, %). As a result, the betamethasone concentration in the medium and skin could
both be detected, which suggested that betamethasone dipropionate could be metabolized to betamethasone
through the tissue engineering skin.
Conclusion: It was feasible to use tissue engineering skin as a model to study the dermatopharmacokinetics
of topical betamethasone dipropionate gel. The research could build a foundation for
the dermato-pharmacokinetic study approach.