title: Stability of a novel corticosteroid nasal irrigation solution: betamethasone 17-valerate added to extemporaneously prepared nasal irrigation solutions.
abstract: There are no commercially available nasal irrigation solutions containing corticosteroids. Instead, such preparations are extemporaneously prepared by adding existing corticosteroid formulations to nasal irrigation solutions. The stability of the corticosteroid betamethasone 17-valerate (B17V), in nasal irrigation solutions of different compositions and pH and stored under different temperatures, was studied to determine the optimal choice of solution and storage conditions.
  
  
  
  Triplicate extemporaneous preparations made with B17V were prepared by adding a predetermined volume of B17V lotion to each nasal irrigation solution: normal saline (NS), sodium bicarbonate (NaHCO3) powder dissolved in tap water, and a commercially available powder mixture (FLO Sinus Care Powder), dissolved in tap water or pre-boiled tap water. Preparations were stored at 30°C and 4°C. Sampling was carried out at 0, 1, 2, 6, and 24 hours. The concentrations of B17V and its degradation compound, betamethasone 21-valerate (B21V), were determined by high-performance liquid chromatography.
  
  
  
  Preparations stored at 30°C contained a lower amount of B17V and higher amount of B21V than those stored at 4°C. B17V stability in nasal irrigation solutions decreased in the following order: NS, FLO in fresh tap water, FLO in pre-boiled tap water, and NaHCO3. The degradation rate of B17V increased with higher storage temperature and higher pH.
  
  
  
  B17V is most stable when added to NS and least stable in NaHCO3solution. FLO solution prepared with either cooled boiled water or tap water is an alternative if administered immediately. Storage at 4°C can better preserve stability of B17V, over a period of 24 hours.
authors.affiliation: Department of Pharmacy, Singapore General Hospital, Singapore.|Allergy Centre, Singapore General Hospital, Singapore.
authors.forename: Kheng Yong
authors.initials: KY
authors.lastname: Ong
authors.affiliation: Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore.
authors.forename: Wei Ching
authors.initials: WC
authors.lastname: Lim
authors.affiliation: Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore.
authors.forename: Shing Ming
authors.initials: SM
authors.lastname: Ooi
authors.affiliation: Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore.
authors.forename: Zhi Hui
authors.initials: ZH
authors.lastname: Loh
authors.affiliation: Department of Pharmacy, Singapore General Hospital, Singapore.|Allergy Centre, Singapore General Hospital, Singapore.
authors.forename: Ming Chai
authors.initials: MC
authors.lastname: Kong
authors.affiliation: Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore.
authors.forename: Lai Wah
authors.initials: LW
authors.lastname: Chan
authors.affiliation: Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore.
authors.forename: Paul Wan Sia
authors.initials: PWS
authors.lastname: Heng
mesh_terms: D000893:Anti-Inflammatory Agents / Q000737:chemistry*; D001624:Betamethasone Valerate / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D005938:Glucocorticoids / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D055556:Nasal Lavage; D019999:Pharmaceutical Solutions; D013696:Temperature
chemical_list: D000893:Anti-Inflammatory Agents; D005938:Glucocorticoids; D019999:Pharmaceutical Solutions; D001624:Betamethasone Valerate
keywords: betamethasone; chronic rhinosinusitis; corticosteroid; intranasal administration; nasal irrigation; sinus surgery