Development of two stable oral suspensions of levodopa-carbidopa for children with amblyopia

Purpose: To develop stable liquid dosage forms of levodopa-carbidopa for us e in children with amblyopia. Methods: Levodopa (100 mg) and carbidopa (25 mg) tablets were used to prepa re the suspensions at 5 and 1.25 mg/mL, respectively. For each suspension, five bottles were stored at 25 degreesC and five at 4 degreesC. Three sampl es were taken from each bottle at 0, 7, 14, 28, 42, 56, 70, and 91 days (n= 15). Levodopa-carbidopa concentrations for each sample were measured in dup licate by validated and stability-indicating high-performance liquid chroma tographic method. Results: The mean concentrations of levodopa-carbidopa in Ora Plus/Ora Swee t suspensions were 96% and 92% of the initial concentrations for 28 days at 25 degreesC, and 94% and 93% for 42 days at 4 degreesC. in the suspension containing ascorbic acid, the mean concentrations of levodopa-carbidopa wer e above 93% and 92% for 14 days at 25 degreesC, and 93% and 92% for 28 days at 4 degreesC. This liquid formulation was administered to 15 children (me an age: 5.6+/-1.4 years) with amblyopia. The number and type of adverse eff ects were similar in the levo-dopa-carbidopa versus placebo group. Conclusion: Levodopa-carbidopa in extemporaneous suspensions prepared in Or a Plus and Ora Sweet were stable for 28 days when stored at 25 degreesC and for 42 days at 4 degreesC. Our data suggest our liquid formulation may be used safely in children with amblyopia.