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To the Editor. With the evolution of today's specialized therapy, the role of the compounding pharmacist in the practice of pharmacy is more evident than ever. The art and science of compounding allows the pharmacist to prepare dosage forms that best suit the needs of individual patients. For several years compounding has been on the rebound, influenced by the modernized practice of pharmacy. In the United States, compounded prescriptions occupy a growing portion of the drug market and account for 250 million prescriptions annually.1 Patients and the Food and Drug Administration have entrusted compounding pharmacists with preparing these compounded preparations. Although the state pharmacy boards regulate and guide compounded preparations, they are seldom analyzed for quality, and it is left to the individual pharmacist to assure the quality.
In 2001, the FDA's Division of Prescription Drug Compliance and Surveillance conducted a limited survey of common drugs and dosage forms compounded by 12 pharmacies located throughout the United States2. This survey enabled the FDA to assess quality, purity, and potency of the compounded drug products. Twenty-nine samples were collected and subjected to original and repeated analytical testing during the survey. Ten (34%) of 29 sampled products failed standard quality tests. Nine of the 10 products failed potency testing (less of the active ingredient(s) than declared on the label) with a failure range of 59 to 89%.
In 2006, the FDA conducted a second survey in which it collected both active pharmaceutical ingredients (API) and finished compounded drug products from compounding pharmacies.3 Of the 36 samples analyzed, 12 (33%) failed analytical testing, with potency ranging from 67.5% to 268.4% of the amount declared on the label.
Both studies by the FDA confirm that the pharmacy profession has the opportunity to make an important contribution to the quality of preparations compounded in laboratories and pharmacies. In order to maintain the highest professional standards and ethics, we have to identify the sources of error that may affect the quality of these preparations so we can reexamine our compounding techniques and modernize them where needed.
There have been few if any academic reports describing the incorporation of analytical testing within the compounding teaching laboratory. We decided to integrate the analytical component into our compounding curricula to evaluate students' skills, performance, and competency. For this purpose, we set up a special session in the advanced compounding laboratory where we analyzed a suppository from each student and reported the result to the student.
We started this exercise in fall 2008. Students prepared progesterone, 25mg, suppositories using PEG bases as directed. Students had no previous knowledge that their preparations would be analyzed. A United States Pharmacopeia (USP) method was adopted for analyzing the suppositories using high performance liquid chromatography (HPLC). The same testing was also repeated with a different class in the fall of 2009. This class was informed about the suppository analysis before preparation. The results of the potency testing in 2009 were better than 2008; thus, this exercise showed that analytical testing is crucial and needed.
More attention must be focused on the potency and strength of compounded preparations, and students should be aware of the consequences if they do not adhere to the appropriate guidelines. The most likely source of error for this experiment was the improper incorporation and mixing technique for progesterone with the melted PEG base prior to pouring into the molds. However, this stresses the importance of attaining a simple compounding technique and justifies the need to address the preparation of more challenging formulations. The FDA's findings from both surveys did not elaborate on the sources of error in their findings.
Our aim was to help the students gain more knowledge about the steps taken for the development of an analytical method, and to better guide them in the pursuit of reasonable explanations for why their suppositories failed the potency and strength test. When student results fall outside of the acceptable range, they understandably will begin to question the importance of proper mixing and compounding techniques.
In this regard, we are calling for a widespread effort at the academic level to address this problem. Our task as academicians is to ensure the quality of teaching and learning, and analytical testing is the proper tool to preserve the quality and integrity of compounding. We call upon every college and school of pharmacy to incorporate some type of analytical testing in compounding laboratories, leaving no doubt that our pharmacy students and professional pharmacists are always striving to perform their duties to the highest standards. Compounding requires diligence and careful attention to small details, and we are committed to pursuing more rigorous academic solutions to this problem. In the meantime, we are hopeful that most institutions will begin to incorporate analytical testing to instill in the minds of the students the importance of potency, strength, and quality of preparations, and strengthen their compounding skills and mixing techniques.