Pharmaceutical Oral Formulation of Methionine as a Pediatric Treatment in Inherited Metabolic Disease.

L-Methionine (Met) is an essential alpha-amino acid playing a key role in several metabolic pathways. Rare inherited metabolic diseases such as mutations affecting the MARS1 gene encoding methionine tRNA synthetase (MetRS) can cause severe lung and liver disease before the age of two years. Oral Met therapy has been shown to restore MetRS activity and improve clinical health in children. As a sulfur-containing compound, Met has a strongly unpleasant odor and taste. The objective of this study was to develop an optimized pediatric pharmaceutical formulation of Met powder, to be reconstituted with water, to obtain a stable oral suspension. Organoleptic characteristics and physicochemical stability of the powdered Met formulation and suspension were evaluated at three storage temperatures. Met quantification was assessed by a stability-indicating chromatographic method as well as microbial stability. The use of a specific fruit flavor (e.g., strawberry) with sweeteners (e.g., sucralose) was considered acceptable. No drug loss, pH changes, microbiological growth, or visual changes were observed at 23 ± 2 °C and 4 ± 2 °C with the powder formulation for 92 days, and the reconstituted suspension for at least 45 days. The developed formulation facilitates the preparation, administration, the dose adjustment and palatability of Met treatment in children.

Stability of pemetrexed diarginine concentrates for solution in vials and diluted in 0.9% sodium chloride and dextrose 5% polyolefin infusion bags.

OBJECTIVES: To determine the physicochemical stability of pemetrexed diarginine in original vials, and after dilution in two commonly used infusion fluids (0.9% sodium chloride, 5% dextrose) in polyolefin bags, stored under refrigeration (2-8°C) or at ambient temperature (22-25°C) exposed to light. METHODS: Stability of pemetrexed diarginine injection concentrate was determined in the original glass vials with closed-system transfer device. Diluted pemetrexed diarginine infusion solutions were aseptically prepared by dilution of pemetrexed diarginine concentrate with either 0.9% sodium chloride or dextrose 5% in polyolefin bags, in amounts yielding pemetrexed diarginine concentrations of 4, 9 and 12 mg/mL. Test solutions were stored under refrigeration (2-8°C) or at ambient temperature (22-25°C) exposed to light. Pemetrexed diarginine concentrations were determined throughout a 14-day storage period using a stability-indicating HPLC assay. In addition, test solutions were visually examined for colour change and precipitation. RESULTS: Pemetrexed diarginine injection concentrate with closed-system transfer device is shown to be physicochemically stable for up to 4 days when stored under refrigeration and for 1 day at room temperature. A browning of the pemetrexed diarginine concentrate solutions appeared 0n day 2 when stored at ambient temperature and on day 5 under refrigeration. Pemetrexed diarginine diluted in dextrose 5% and 0.9% sodium chloride was physicochemically stable for up to 4 days when stored under refrigeration and for 1 day at room temperature. A browning of the diluted solutions appeared on day 2 when stored at room temperature and on day 5 when stored under refrigeration. CONCLUSIONS: Pemetrexed diarginine concentrate for solution stored under refrigeration with closed-system transfer device can be retained as a residual to reduce product losses. The analytical stability of pemetrexed diarginine in dextrose 5% and 0.9% sodium chloride under refrigeration enables our centralised unit to prepare this drug in advance.