Physicochemical and microbiological stability studies of a melatonin oral suspension in a commercially available vehicle for paediatric use

Abstract

Objectives Melatonin is commonly prescribed in paediatric population, but it is commercially only available in tablet form. Oral suspensions are useful pharmaceutical preparations faced with difficulties from the pharmaceutical industry to provide medicines to children. Ready-for-use suspending agents are used, although their compositions are unsuitable for children. A new liquid vehicle for oral suspensions, Inorpha, was commercialised with a formulation adapted in paediatrics. The stability of a melatonin oral suspension 2 mg/mL in Inorpha was studied. The physicochemical and microbiological stabilities were respectively evaluated during 6 and 4 months. Methods A validated high-performance liquid chromatography method was used to assess the melatonin concentration under room temperature and refrigerated conditions weekly. A validated microbiological method was employed on 10 mL vials, on the one hand, and one 200 mL bottle opened every day, on the other hand, in order to evaluate respectively the microbiological stability before opening and under conditions of use. Results After 18 weeks under room temperature and refrigerated conditions, samples held respectively a melatonin minimal concentration of 99.3% and 96.7% of initial concentration. After 6 months, melatonin concentration was 96.1% of initial concentration. Total aerobic microbial counts obtained during the 4-month microbiological study were <10 CFU/mL. None of the melatonin suspensions presented fungal growth. Conclusions Variation of the active ingredient concentration did not exceed 5% after 6 months. Microbial enumeration assays demonstrated microbiological stability of suspensions over a period of 4 months. The microbiological quality was not altered by repeated openings of the bottle allowing production of multidose vials.

Evaluation of stability of melatonin in extemporaneously compounded oral suspensions

“…It is also available as intraoral sprays and oral liquids containing alcohol. Melatonin is commonly used as a sleep aid to modulate sleeping patterns . Additionally, it is sometimes used to slow the advancement of neurodegenerative diseases …”

“…Melatonin is commonly used as a sleep aid to modulate sleeping patterns. 7,8 Additionally, it is sometimes used to slow the advancement of neurodegenerative diseases. 6,7 This study is aimed at establishing the chemical stability of extemporaneously prepared melatonin formulations using proprietary Oral Mix SF (Medisca Pharmaceutique Inc, Montreal, QC, Canada).…”

Stability of refrigerated miglustat after preparation in InOrpha&reg; flavored suspending excipient for compounding of oral solutions and suspensions

“…It has successfully been used as a suspending vehicle for hydrocortisone 8 and melatonin. 9 The aim of this study was to evaluate the stability of miglustat preparations when dissolved in InOrpha ® suspending vehicle with regard to physicochemical and microbiological properties.…”