Stability of mupirocin ointment (Bactroban) admixed with other proprietary dermatological products

Abstract

This study involved the mixing of 1:1 combinations of Bactroban (mupirocin) Ointment 2% with various cream, lotion, ointment, gel, solution and liquid soap formulations with storage at 37 degrees C for 60 days. The mixtures were assayed for mupirocin content at 0, 15, 30, 45 and 60 days using a high-pressure liquid chromatographic (HPLC) assay. At the time of preparation of these admixtures, Bactroban Ointment is chemically and physically compatible with all of the topical dermatological products studied except for Valisone lotion where a physical incompatibility is immediately observed. Admixtures of Hibiclens liquid soap or Lotrimin solution with Bactroban Ointment were stable throughout the entire 60-day study. Combinations of Lotrimin cream, Hytone cream, Valisone ointment or Vytone cream with Bactroban Ointment also retained chemical stability of mupirocin for the entire period even though two layers were observed and mixing was required to restore a physically homogenous mixture. Other Bactroban Ointment admixtures were found to be either chemically stable for mupirocin for periods less than 60 days or physically incompatible mixtures were observed upon storage. No conclusions were drawn from these studies concerning the efficacy or safety of any of these products when used in extemporaneously prepared combinations.

Development and validation of a liquid chromatographic method for in vitro mupirocin quantification in both skin layers and percutaneous penetration studies

“…The concentration of mupirocin in the receptor 9 hours after the topical application was 6.09 μg/ml ( Figure 3). The retention of mupirocin in the stationary phase was 5.93±0.02 (k' value) and acceptable asymmetry coefficient was obtained (the asymmetry coefficient was 0.98±0.09), while the peak tailing factor obtained by Jagota et al [18] was near to 1.5. Under the chromatographic conditions used, mupirocin has a retention time of 7.20±0.07 min.…”

“…The HPLC method described in this paper was based on that developed by Jagota et al [18]. Although some modifications were made in order to obtain a better sensibility for the diluted samples in the permeation studies and avoid interferences with the skin compounds.…”

“…Under the chromatographic conditions used, mupirocin has a retention time of 7.20±0.07 min. Jagota et al [18] obtained a retention time of 5.5 ± 0.5 min using a octadecylsilane non-encapped stationary phase packed with 10 μm-silica particle size.…”

“…For ruggedness studies, columns packed with Kromasil ® , Ultrabase ® and Spherisorb C 18 ® stationary phases were used and it resulted in a worse characterization of mupirocin peak due to its lower polarity (different asymmetry coefficients) but it did not change the elution time. If the temperature of the column was decreased to 25ºC, the symmetry of the peak also differed more from 1, so the temperature was adjusted to 45ºC with a consequent improvement of the asymmetry coefficient and no variations in elution time.…”

“…None of the previously reported methods determined mupirocin both in skin layers and percutaneous penetration samples, furthermore some methods were developed for estimation of mupirocin purity and degradation by HPLC [18], ELSD-HPLC [19] and mass spectral and liquid chromatography [20]. Jagota et al [18] The HPLC method described in this paper was based on that developed by Jagota et al [18]. This method has been successfully applied to determine the concentration of the analyte in the in vitro percutaneous penetration studies, through porcine skin, using Franz-type diffusion cells.…”