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Control principles of sterile product preparation

The environmental controls of preparing sterile products.
To protect the sterile product and then protect patient require good environmental control The environmental control could be divided as the primary engineering controls and secondary engineer control The primary engineer control refers to create and maintain the ISO class 5 environment This covers the horizontal laminar airflow workbench for non-hazardous drugs and vertical biological safety cabinet for hazardous drug preparation The secondary engineer control refer to the area surrounding the primary engineer control or called buffer area This area includes clean room and ante area These environment need to achieve ISO class 7 for clean room and ISO class 8 for ante area Biological safety cabinets are intended to protect the user and environment from the hazards associated with the handling of infectious material and other biohazardous material Some types also protect the materials being handled in them from contamination The Class I Biological safety cabinets provides personnel and environmental protection but no product protection It is similar in air movement to a chemical fume hood but has a HEPA filter in the exhaust system to protect the environment In the Class I Biological safety cabinets unfiltered room air is drawn across the work surface Personnel protection is provided by the inward airflow as long as a minimum velocity of 75 linear feet per minute is maintained through the front opening The Class I Biological safety cabinets is hard-ducted to the building exhaust system and the building exhaust fan provides the negative pressure necessary to draw room air into the cabinet
The Class II biological safety cabinets it could be divided or classified as Types A B1 B2 and B3 they provide personnel environmental and product protection Airflow is drawn around the operator into the front grille of the cabinet which provides personnel protection In addition the downward laminar flow of HEPA-filtered air provides product protection by minimizing the chance of cross-contamination along the work surface of the cabinet Because cabinet air has passed through the exhaust HEPA filter it is contaminant-free
so it will protect the environment and may be re-circulated back into the laboratory
or ducted out of the building
All Class II cabinets are designed for work involving microorganisms assigned to biosafety levels 1 2 and 3 Class II cabinets provide the microbe-free work environment necessary for cell culture propagation and also may be used for the formulation of nonvolatile antineoplastic or chemotherapeutic drugs
An internal blower draws sufficient room air through the front grille to maintain a minimum calculated or measured average inflow velocity of at least 75 lfpm at the face opening of the cabinet The supply air flows through a HEPA filter and provides particle-free air to the work surface
Laminar airflow reduces turbulence in the work zone and minimize the potential for cross-contamination The downward moving air splits as it approaches the work surface the blower draws part of the air to the front grille and remainder to the rear grille Although there are variations among different cabinets this split generally occurs about halfway between the front and rear grilles and two to six inches above the work surface The air is then discharged through the rear plenum into the space between the supply and exhaust filters located at the top of the cabinet
Due to the relative size of these two filters approximately 30 percent of the air passes through the exhaust HEPA filter and 70 percent re-circulates through the supply HEPA filter back into the work zone Most Class II Type A cabinets have dampers to modulate this 30 over 70 division of airflow The cabinets supply blowers draw room air plus a portion of the cabinet’s re-circulated air through the front grille and then through the supply HEPA filters located immediately below the work surface
This particle-free air flows upward through a plenum at each side of the cabinet and then downward to the work area through a backpressure plate In some cabinets there is an additional supply HEPA filter to remove particle that may be generated by the blower or motor system Room air is drawn through the face opening of the cabinet at a minimum inflow velocity of 100 lfpm As with the Type A cabinet there is a split in the down-flowing air stream just above the work surface In the Type B cabinet approximately 70 percent of the downward flow air exits through the rear grille passes through the exhaust HEPA filter and is discharged from the building The remaining 30 percent of the down flow air is drawn through the front grille Since the air which flows to the rear grille is discharged into the exhaust system activities that may generate hazardous chemical vapors or particulates should be conducted toward the rear of the cabinet

When patients need to use sterile medications, it is important to ensure the medications are safe to use.

The first step of protect sterile production preparation is to make sure the environment is under total control. In this video, Deputy Chiang will introduce the principles of it.

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