The impact of semisolid matrices on spreadability, rheology and celecoxib release rate.

Background: The results of numerous research studies published in recent years suggest that celecoxib (CEL) may be effective in the treatment of various skin disorders. However, to date, no semisolid product containing CEL has been launched.

Objectives: With a focus on the future development of topical products, we aimed to investigate the impact of different semisolid matrices on the in vitro performance of CEL.

Material and methods: For this purpose, 1% (w/w) of the drug was suspended in 4 compounding vehicles available in Polish community pharmacies: Lekobaza (amphiphilic cream), Lekobaza Lux (hydrophobic cream), Celugel (hydrogel), and Oleogel (lipogel). Given their very different physicochemical properties, our goal was to analyze, for the first time, their influence on spreadability, viscoelastic properties and the release rate of CEL.

Results: It was found that all of the semisolid matrices were suitable as vehicles for the drug in terms of spreadability and rheological stability. The viscous properties predominated when Celugel was used as a vehicle, but when Lekobaza, Lekobaza Lux and Oleogel were tested, the elastic properties prevailed. The drug release rate was the highest when hydrophilic matrices, i.e., Celugel or Lekobaza were used, but when hydrophobic matrices such as Lekobaza Lux or Oleogel were examined, CEL was released slowly. These findings might be related not only to the properties of these matrices, but also to the design of the release study that was more suitable for evaluating the hydrophilic matrices.

Conclusions: Celugel could be particularly useful as a vehicle for CEL for the therapy of large lesions with heavy exudation, but if there is a risk of skin drying out after using the hydrogel, the use of Lekobaza can be recommended.