By Melissa Merrell Rhoads, PharmD, PCCA Director of Formulation Development

As I wrote in the first part of this article, on June 1, 2019, the United States Pharmacopeial Convention published revisions to the compounding Chapters <795> and <797> in the United States Pharmacopeia and National Formulary, which were set to become official on December 1. However, USP later announced that they would postpone that official date because of pending appeals to certain parts of the revised chapters. The revisions in USP <795> and <797> affect the beyond-use date (BUD) that can be applied to compounded formulations, among other standards.

Even though the date when the revised chapters become official is postponed, our Formulation Development department is working on updates to our formulas to be compliant with the new USP standards. We will complete these updates within our formulation database when we are notified of the new official date and contents of the Chapters <795> and <797>, and they will go into effect in our database on the day that they become official. Therefore, it will be important for PCCA members to download the latest versions of PCCA formulas after the date that the new chapters become official (which has not been announced yet), as there will be changes that should be noted and documented for master formulas.

Therefore, we wanted to announce what these future changes will look like. Below is a summary of the formula changes based on the latest version of USP Chapter <797> as it is written currently. We will make further changes as needed based on the appeals outcome, and we will announce those changes as well.

Changes Related to USP <797>
Sterilization Procedures
Section 10 of the revised USP Chapter <797> discusses sterilization and depyrogenation for compounded sterile preparations (CSPs). The method of sterilization plays a role in establishing the BUD for CSPs. The chapter establishes two categories for CSPs: aseptically processed, which are sterilized by filtration, and terminally sterilized, which are sterilized by steam heat (autoclaving) or dry heat. We will update PCCA formulas to reflect these compounding processes and provide specific instructions to render the preparations sterile.

BUDs
Section 14 of USP Chapter <797> discusses the parameters for establishing BUDs for CSPs. Table 11 of the chapter covers the parameters in detail, but the BUDs are based primarily on factors that affect the achievement and maintenance of sterility (risk of microbial contamination). The chapter assumes that CSPs will remain chemically and physically stable within the container-closure systems used. Chapter <797> does not provide specific direction on chemical stability, but requires that compounders consider the chemical and physical properties of the drug and/or its formulation as well as the compatibility of the container-closure system with the finished preparation. Since establishing a BUD per these new guidelines depends on multiple factors, our sterile formulas (outside of FormulaPlus formulas) will no longer assign a specific BUD, but will rather provide the relevant guidelines for compounders to determine the maximum BUD they will be able to assign based on whether sterility testing was performed and passed and the temperature at which the preparation will be stored.

According to USP Chapter <797>, a multiple-dose CSP must additionally pass antimicrobial effectiveness testing in accordance with USP Chapter <51>. After the multiple-dose CSP is dispensed, and upon initially entering or puncturing the container for the first time, “the multiple-dose container must not be used for longer than the assigned BUD or 28 days if supported by antimicrobial effectiveness testing results (see <51>) on the CSP, whichever is shorter.” As an alternative, compounders may dispense the preparation in smaller, sealed, single-use, sterilized and depyrogenated container-closure systems. 

According to the new guidelines as they are currently written in USP Chapter <797>, there are no means to extend a BUD beyond the dates listed in Table 11. However, PCCA’s data on our sterile FormulaPlus formulas is still a valuable resource. Since USP <797> does not address chemical stability, these studied formulas provide documented chemical stability and therefore ensure the chemical and physical stability of the preparation. We have 12 sterile FormulaPlus formulas, and several are bracketed studies allowing for a broad range of active ingredient concentrations. PCCA members can view these in the FormulaPlus master list.

Given the significant changes in pharmacy compounding recently, it is as important as ever to ensure that compounders comply with the latest standards. We hope that the updates we will make to our formulas when the new USP <795> and <797> become official — as well as the change we’ve implemented for compliance with USP <800> — will help them do just that. If PCCA members with Clinical Services access have questions about any of these changes, they can contact our Clinical Services department.

Melissa Merrell Rhoads, PharmD, PCCA Director of Formulation Development, received her pharmacy degree from Mercer University in Atlanta, Georgia, in 1995. She currently is involved with and oversees the development and implementation of new formulas at PCCA. She had more than six years of compounding experience with pharmacies in Georgia and Florida prior to joining the PCCA staff in 2004. Her areas of interest include women’s health, veterinary and pain management compounding.

A version of this article previously appeared in PCCA’s members-only magazine, the Apothagram. PCCA members can find a more detailed description of these formula changes in the Fall 2019 issue.

Reference
United States Pharmacopeial Convention. (2019). General chapter <797> pharmaceutical compounding — Sterile preparations. In United States pharmacopeia and national formulary (USP 42nd ed. & NF 37th ed.). Rockville, MD: United States Pharmacopeial Convention, Inc.