Spironolactone Liquid Formulation Composition and Palatability
The FDA-approved liquid formulation of spironolactone (CaroSpir®) is a banana-flavored oral suspension based in a co-solvent system, and it is specifically designed to be more palatable than tablets, particularly for patients who have difficulty swallowing.
Formulation Base and Ingredients
The liquid spironolactone formulation uses a co-solvent blend system to solubilize the drug, which is practically insoluble in water 1. Research formulations have successfully used combinations of:
- Polyethylene glycol 400 (30% v/v)
- Propylene glycol (10% v/v)
- Glycerin (10% v/v)
- Ethyl alcohol (10% v/v)
These co-solvents work together to achieve adequate drug solubilization at therapeutic concentrations 2.
Palatability Enhancement
Yes, the liquid form is significantly more tasteful than tablets. The commercially available CaroSpir® comes as a banana-flavored oral suspension containing 25 mg/5 mL of spironolactone 3.
Research formulations have incorporated multiple palatability-enhancing agents 2:
- Sweetening agents (sucrose, saccharin sodium)
- Flavoring agents (cherry, sweet flavors)
- Desensitizing agents (menthol) to mask any unpleasant taste
- Coloring agents (FD&C Red #40)
- Preservatives (benzoic acid)
- pH buffering (phosphate buffer at pH 4.5 for stability)
Alternative compounded formulations using PCCA base SuspendIt have also been developed, which is sugar-free, paraben-free, dye-free, and gluten-free, containing natural sweetener from monk fruit 4.
Clinical Advantages
The liquid formulation was specifically FDA-approved in 2017 to address a critical patient population: those who have difficulty swallowing or are unable to swallow tablets 3. This is particularly relevant for:
- Elderly patients with heart failure
- Pediatric patients
- Patients with dysphagia
- Those requiring precise dose titration
The liquid suspension maintains the same therapeutic efficacy as tablets while providing improved administration ease and patient compliance, without compromising the drug's stability (stable for at least 180 days when properly stored) 4.