Sublimation of Drugs from the Site of Application of Topical Products

The objective of the project was to investigate the plausibility of active pharmaceutical ingredients (APIs) to undergo sublimation from topical application follow i n g evaporation of solvent. Topical formulations with different APIs were subjected to a sublimation screening test. The APIs in the selected topical products were found to undergo sublimation to a different extent. The salicylic acid topical product was found to undergo a significant loss due to sublimation. The extent of sublimation of salicylic acid was significa n t l y greater at skin temperature compared to room temperature. When the APIs were subjected to the sublimation screening test in their neat form at 32 +/- 1 degrees C, the natural log of the rate of sublimation decreased linearly with the standard enthalpy of sublimation of compound (R2 = 0.89). The formulation composition was found to have a significant impact on the extent of sublimation of the representative API , salicylic acid. The sublimation of APIs from the topical product was found to affect the mass balance studies in the case of the salicylic acid ointment. Furthermore, the results of the human studies agreed with the in vitro experimental results demonstrating the plausibi l i t y of loss of API due to sublimation from the site of application.

Automated summary

The objective of this study was to investigate the possibility of active pharmaceutical ingredients (APIs) to undergo sublimation after solvent evaporation from topical application. Different topical formulations containing APIs were tested for sublimation, and it was found that the extent of sublimation varied among the selected products. Salicylic acid, one of the APIs, experienced significant loss due to sublimation, which was more pronounced at skin temperature compared to room temperature. Furthermore, the formulation composition had a significant impact on the extent of sublimation, particularly for salicylic acid. The sublimation of APIs from the topical product affected the mass balance studies conducted on the salicylic acid ointment. Additionally, human studies yielded results consistent with the in vitro experiments, confirming the plausibility of API loss through sublimation at the site of application.