Critical appraisal of commercially available suspending vehicles for extemporaneous compounding of cardiovascular medicines: physical and chemical stability mini review

Oral liquid formulations are compounded by pharmacists to meet the needs of patients when a suitable commercially available product is not available. To minimise the errors associated with measuring multiple excipients and to enhance the shelf-life of the medicines, commercially available suspending bases are commonly used. This review aims to compare the stability and shelf life of commercially available extemporaneous formulation to traditional formulation methods. Five (5) databases were searched (Pubmed, SCOPUS, Science direct, Embase and EBSCOhost). Twelve articles, comprising of seven cardiovascular medications (amiodarone, captopril, carvedilol, furosemide, nifedipine, sotalol and valsartan), met the study inclusion criteria and were reviewed. Chemical stability of the drugs was comparable between the two formulation methods except for furosemide, captopril and valsartan. The traditional compounding method provided superior stability for furosemide (90 days vs 14 days) and captopril (50 days vs 14 days), while the commercial vehicles provided superior stability for valsartan (90 days vs 14 days). Physical stability tests indicated that sedimentation does occur with both formulation methods. Microbial studies within the data were lacking and further research can be undertaken in this area. This review highlights the importance of assessing the suitability of compounding ingredients prior to preparation of the formulation.