Background Pharmacists rely heavily on available reference material to guide the extemporaneous compounding of medicines. Extemporaneous compounding for individual patients has traditionally not been closely regulated, but is necessary in every setting.

Objective To assess the adequacy of the evidence and recommend changes for the master formulae (MFs) used in the extemporaneous compounding manual at five Ministry of National Guard Health Affairs (MNGHA) tertiary care institutions in Saudi Arabia.

Method A descriptive cross-sectional study of all extemporaneous oral liquid dosage forms (n=75) was conducted. Investigators sought to establish if the current list of compounded oral liquid dosage forms were registered commercially, backed by a stability study or followed the Saudi Arabia Food and Drug Administration guidance on assigning beyond-use dates. A literature review of stability studies, tertiary references and package inserts was used to verify the MFs. Findings of each MF were tabulated and compared with available stability studies.

Results It was found that 28 (37.3%) oral liquid dosage forms were registered by a regulatory authority, 8 (10.7%) MFs could not be traced to a stability study, while 3 (4%) MFs used beyond-use dates. The taskforce approved 15 (20%) MFs without changes, while 42 (56%) MFs had to be revised.

Conclusion This review found that, although resources on the compounding of oral liquid dosage forms exist, pharmacies need to carefully assess their quality and relevance and update local policies and practices. The majority (80%) of the current MFs used in MNGHA institutions were rejected due to inappropriate compounding practices and inaccuracies.