Development and validation of LC/ESI-MS method for the detection and quantification of exogenous ceramide NP in stratum corneum and other layers of the skin

Ceramides (CERs) are integral parts of the intercellular lipid lamellae of the stratum corneum (SC), which provide the barrier function of the skin. Administration of CERs deep into the SC may help to restore the barrier function in affected or aged skin. However, quantification of the amount of CER penetrated into the target site needs a selective and sensitive analytical method. Therefore, an LC/ESI-MS method was developed and validated for the detection and quantification of exogenous CER [NP] in the SC as well as other skin layers. The strategy involved synthesis of ceramide [NP]-D3-18 (deuterated CER [NP]) to distinguish it from the endogenous CER [NP] in MS on weight basis. The method was linear over 10–800 ng/ml and sensitive with a limit of detection (LOD) and limit of quantification (LOQ) of 3 and 10 ng/ml, respectively. It was also accurate with within-run and between-run percentage recoveries of 97.1–103.2 and 99.0–104.9, respectively. The within-run and between-run relative standard deviations (RSDs) were 0.9–5.4% and 2.1–7.4%, respectively, suggesting the method is precise. The method was highly selective and the matrix effect was too minimal with matrix factor (MF) mean and RSD values of 1.002 and 4.57%, respectively.

► Ceramide [NP]-D3-18 was synthesized from phytosphingosine and 18,18,18-D3-octadecanoic acid.
► LC/ESI-MS method was developed for quantification of exogenous ceramide [NP] in the stratum corneum.
► LC/ESI-MS method was validated for quantification of exogenous ceramide [NP] in the stratum corneum.