Advanced Bisoprolol Oral Liquid Formulations for Flexible Pediatric and Geriatric Pharmacotherapy

The increasing demand for oral liquid formulations (OLFs), highlights the need to optimize pharmacotherapy in pediatric and geriatric populations, where swallowing difficulties and dose individualization are critical. One such drug is bisoprolol, a highly selective β1-adrenergic receptor blocker widely used in the management of cardiovascular diseases, for which individualized dose titration is frequently required, particularly in pediatric and geriatric patients. Conventional solid dosage forms often lack the flexibility required, potentially compromising adherence and increasing the risk of medication errors. This study aimed to develop safe, stable, and palatable OLFs of bisoprolol fumarate suitable for individualized dosing. A Quality by Design (QbD)-oriented approach was employed to define the Quality Target Product Profile (QTPP) and identify Critical Quality Attributes (CQAs), including drug content, pH, and organoleptic properties. Two sets of formulations were prepared: sugar-free drops and syrups, each at two strengths (2.5 and 5.0 mg mL^-1). Physical, chemical, and microbiological stability were assessed over 12 months under long-term (4 °C and 25 °C) and 6 months under accelerated conditions (40 °C), using a validated methodology. All formulations remained within predefined specifications, showing no significant degradation or physicochemical changes. Microbiological quality and palatability were maintained throughout the study. These findings demonstrate that the strategy based on QbD principles enables the development of robust, patient-centric OLFs, representing a reliable alternative to extemporaneous preparations and supporting safer, more flexible cardiovascular therapy.