Formulation and Development of Solifenacin Succinate Oral Suspension

Solifenacin succinate is prescribed for patients with overactive bladder (OAB) syndrome to address symptoms such as urge incontinence, increased urinary frequency, and urgency. Tablet formulations can be challenging or impossible to administer to patients who are unable or unwilling to swallow solid dosage forms like tablets or capsules. For these patients, a liquid formulation of Solifenacin succinate is a more suitable alternative. The goal was to develop a liquid formulation with reduced astringency and bitterness compared to Solifenacin succinate in its raw form, while ensuring good drug content homogeneity. A Solifenacin succinate suspension was developed and evaluated based on parameters including pH, density, viscosity, % assay, and drug release profile. Batch optimization was carried out using design of experiment (DoE) software. The optimized formulation was subjected to stability studies as per ICH guidelines. Trial batches played a crucial role in formulating the suspension. Suspending agent (MCC/CMC sodium), viscosity modifier (Xanthan gum) and sweetener (Xylitol) were considered as independent variables and viscosity, dissolution and content uniformity, the suspension batch was optimized with a desirability score of 0.63 using DoE software. The optimized batch demonstrated stability and successfully passed the stability tests. A stable oral suspension dosage form of the antimuscarinic drug Solifenacin succinate was successfully developed, meeting pharmacopoeial standards and offering a patient-friendly alternative for those with difficulty swallowing solid dosage forms.