RESUMEN
INTRODUCTION: Student-compounded sterile preparations have been evaluated using observational scores, sterility testing, and potency determinations. Observational scores and potency determinations can be evaluated simultaneously, and three studies have been published using these assessment tools. One study found a significant number of students could not compound an acceptably potent preparation despite receiving very good observational scores. The previous study was judged to have an inferior instructional flaw, so a new teaching design, a "practice makes perfect" model, was utilized and was expected to increase the number of students compounding acceptably potent preparations. METHODS: The "practice makes perfect" method provided students with more practice and one-on-one instruction time in aseptic techniques. First-year pharmacy students received both group practice sessions and individualized instruction on six occasions interspersed between three compounding assessments. Observational scores and potency results were compared between this study and the previously published study. RESULTS: The "practice makes perfect" strategy improved students' observational scores but showed inconsistent results in the percentage of students who compounded an acceptably potent preparation and in the potency of preparations compounded by all students. There was no correlation between observational scores and potency values or between observational scores and the percentage of students compounding acceptably potent preparations at each individual observational score. CONCLUSIONS: The study demonstrated that there was either a systematic error in the analytical potency protocol or that the observations made during student compounding were not adequate to identify problems that led to poor potency.