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USP Method <797>

Category Consumer Products Testing
Test USP Method <797>: Pharmecuetical Compounding - Sterile Preparations

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The new USP 797 guidelines are designed to prevent the improper handling and contamination of sterile compounds for certain drugs or biologic preparations. These items include:
1) baths for live tissues and organs
2) opthalmics
3) parenterals
4) tissue implants
5) aqueous nasal and bronchial inhalations
6) irrigating solutions.


The guidelines impact not only the people who prepare the compounded sterile pharmaceuticals (CSPs) but also the areas where theses drugs are prepared and stored including commercial and hospital pharmacies, clinics, doctor’s offices and other facilities. USP 797 recommends certain clean area designs, storage specifications, Quality Assurance plans which include environmental monitoring, and employee training programs to accomplish the safe handling of these preparations.  These guidelines specifically address:
1) microbial contamination
2) endotoxins
3) physical or chemical contamination
4) preparation of incorrect concentrations and
5) incorrect ingredients. 
A mistake in any of these 5 areas can cause serious injury or even death.


While a good portion of the USP 797 guidelines deal with improving air quality in these facilities, an equally important goal is to prevent physical contact with and contamination of these preparations during manufacture.  Products are manufactured according to risk levels: low, medium or high.  Products that are to be injected carry the greatest risk of serious health effects; therefore these products must be manufactured in an area having the lowest risk level for contamination.  The lowest risk level required under USP 797 for a critical area is an ISO Class 5 area designation.


The design of Class 5 clean areas for preparation and Class 7 buffer areas, surrounding Class 5 areas, is a requirement.  Semi-annual monitoring for viable bacteria in air, fingertip, surface contact plates, and particulates is required for both Class 5 and Class 7 designated areas. These monitoring results trended over time will provide information on any deterioration in air quality and aseptic technique.  Generally, this monitoring should be conducted semi-annually.


The action levels for microbial and particulate monitoring results are summarized below:


Semi-Annual Microbial and Particulate Monitoring

ISO Clean Room Classification

US Clean Room Classification

(0.5 u/ft3)



> 0.5 u/m3

Air Sampling

400-1000 L*




Fingertip Sampling



Swab/Surface Contact Plate



Endotoxin (frequency depends on CSP batch numbers/  storage conditions)

Class 5






See USP monographs

Class 7






See USP monographs

Class 8






See USP monographs

* Based on sample volume of 100 lpm


One important item should be noted.  Regardless of the number of CFUs recovered, corrective actions are required if any of the following organisms are identified: 1) Gram negative rods, 2) Coagulase positive Staphylococcus,and 3) Molds and Yeasts. 


For more information concerning these guidelines, please call Diane Miskowski at 800-220-3675 x1218.