Development, Quality by Design-Based Optimization, and Stability Assessment of Oral Liquid Formulations Containing Baclofen for Hospital Use

The absence of oral liquid pharmaceutical forms appropriate for use in pediatric and adult patients with difficulty swallowing is a public health problem, especially in the hospital context. Baclofen is a muscle relaxant of choice for treating spasticity, generally marketed only in tablet form, highlighting the need for liquid formulations to facilitate dose adjustment, administration, and swallowing. The present study aimed to develop oral liquid formulations containing baclofen, optimize them through the quality by design approach, and evaluate their physicochemical and microbiological stability. Preformulation and preliminary stability studies were carried out for the development of formulations. Experimental screening and optimization designs resulted in eleven experiments for each step that were evaluated for 28 days. A stability-indicating method by high-performance liquid chromatography presented linearity, low limits of detection and quantification, precision, accuracy, and robustness. The experimental design led to two optimized formulations containing baclofen, glycerin, potassium sorbate, citric acid, ultrapure water, flavor, and sucrose syrup or sodium carboxymethylcellulose solution as a vehicle, the last one with sucralose as a sweetener. The formulations were placed in amber glass flasks and subjected to a physicochemical and microbiological stability study. Both formulations showed physicochemical and microbiological stability when stored at room temperature and refrigerated for 84 days. The results of this study may serve as a reference in the preparation of liquid oral formulations containing baclofen in the hospital routine and collaborate with the safety and adherence to the treatment of adult and pediatric patients.