CENTRAL MIXING STATION FOR HOSPITALS
- INPAL
- Jun 25
- 13 min read

Central mixing station for hospitals
From a constructive point of view, a blending plant must have differentiated and clearly delimited areas according to the process flow and the type of preparation. Generally, there is an input reception area, a storage area, a preparation area, the clean room where the actual blending takes place, and a control and dispatch area. The clean room is the heart of the plant and is built under clean architecture criteria: smooth surfaces, without joints or cracks, made of materials resistant to disinfectants, and with a design that minimizes the accumulation of particles and facilitates cleaning.
These conditions are achieved through the implementation of specialized HVAC systems (heating, ventilation and air conditioning), with high efficiency HEPA filters, which allow maintaining ISO 7 or 8 room classifications in the support areas, and ISO 5 within the laminar flow cabinets or biological safety cabinets where mixing is carried out. These cabinets not only ensure an ultra-clean environment for product handling, but also protect the operator in case of working with hazardous substances, such as oncological drugs.
In some cases, the plant may include robotic systems for the preparation of mixtures, especially in large hospitals. These automated systems, although costly, offer exceptional levels of accuracy and safety, reducing personnel exposure to hazardous substances and minimizing the risk of contamination.
Central mixing station for hospitals
In addition to the physical and environmental design, the operation within a compounding plant implies a rigorous organization of the workflow, with standardized protocols for each type of preparation. These protocols are developed by the hospital pharmacy service and must be aligned with pharmacological, pharmacokinetic and pharmacodynamic regulations. Each drug being handled has its own requirements for stability, compatibility, sensitivity to light or temperature, and shelf life after reconstitution or mixing. All this must be considered from the moment the plant layout is designed to the training of personnel.
For example, the preparation of parenteral nutrition, which requires a precise mixture of macronutrients and micronutrients, requires a detailed knowledge of the physicochemical principles that affect the stability of lipid emulsions, the compatibility of calcium-phosphate solutions, and the sensitivity of certain vitamins to oxidation. These mixtures are made under total aseptic conditions, usually inside a class II laminar flow hood type A2 or B2, depending on the characteristics of the compound.
In parallel, microbiological monitoring practices of the environment, surfaces, gloves, and personnel are implemented on a routine basis, using sedimentation plates, swabs, or contact tests. This is part of the environmental validation program, which should consistently demonstrate that the area is suitable for sterile drug preparation.
Staff training is another key factor in the efficiency of a plant. Operators-usually pharmacy technicians, under the direct supervision of a clinical pharmacist-must be rigorously trained in aseptic handling techniques, one-way flows, cross-contamination control, proper use of PPE (personal protective equipment), and emergency protocols in case of spills or accidental exposure. In addition, they must undergo regular retraining and proficiency testing, as human error in a highly controlled environment can have severe clinical consequences.
Central mixing plant
From a broader perspective, central compounding centers represent a profound transformation in the way hospital pharmacotherapy is handled. They make it possible to move from a decentralized model, where each clinical unit handles and mixes drugs at the patient's bedside, to a centralized model, where all preparations are carried out under strict quality, control and biosafety standards. This, in addition to reducing the risk of medication errors and increasing efficiency, frees up nursing staff time and improves hospital response times.
Automation Systems
One of the most important components of a mixing plant is undoubtedly the HVAC (Heating, Ventilation and Air Conditioning) system. Unlike a conventional air conditioning system that is limited to maintaining thermal comfort, in a mixing plant the HVAC plays an essential role in biosafety, contaminant control and preservation of environmental sterility.
To achieve this, real-time automation and monitoring systems are implemented, usually integrated into a BMS (Building Management System). These systems allow continuous control over critical environmental variables such as:
Differential pressure between areas (e.g., maintain positive pressure in sterile mixing areas to prevent ingress of particles from less clean areas, or negative pressure in the handling of hazardous drugs to contain contaminants).
Temperature and relative humidity, which must be kept within very strict ranges (usually between 20 and 24°C, with a humidity of 30% to 60%) to ensure drug stability and operator comfort.
Air flow speed and direction, especially in laminar flow or biological safety cabinets, where the flow must be unidirectional and laminar, without turbulence, to avoid particle recirculation.
Airborne particle count, which is a requirement to maintain the ISO classification of the rooms (ISO 5 inside booths, ISO 7 or 8 in adjacent areas).
These automation systems include sensors distributed at strategic points that transmit data to a centralized server or a digital interface accessible to technical and pharmaceutical personnel. Any deviation from the preset parameters triggers an immediate alarm, either visual, audible or digital, which forces the process to be interrupted if necessary. In addition, all data is automatically recorded and stored, allowing historical traceability, trend analysis and regulatory audits.
Beyond HVAC, there are other equally relevant automation systems. One of them is the pharmaceutical production management system. This system is connected to electronic medical prescription, pharmaceutical validation systems and traceability of supplies. It can print labels with unique barcodes for each preparation, manage batches, control expiration dates, validate compatibilities and record the history of each mixture.
In the most technologically advanced plants, robotic mixing systems are implemented, especially for the preparation of chemotherapy or parenteral nutrition. These robots work in controlled environment conditions, reducing human manipulation to a minimum, which translates into greater precision and less risk of error or contamination. Automation of this type not only improves safety, but also increases efficiency and allows the volume of preparations to be scaled up without compromising quality.
Another aspect to consider is the integration of hospital information technology (HIS) with the central mixing station. This integration ensures that all information - from the medical order to patient administration - is synchronized in real time. This avoids duplication, reduces errors and guarantees evidence-based pharmacotherapy and control.
The energy component cannot be left out of this scenario. These systems must have redundant power sources, such as dedicated power plants or UPSs, to ensure continuity of operation of the HVAC, monitoring systems and safety cabinets in case of power grid failures. The stability of the environment cannot be compromised, even for a few minutes, as it could mean the loss of expensive medications or risk to a patient's life.
Hazardous waste management
In a mixing plant, particularly when handling cytotoxic drugs, antineoplastic drugs, biological agents, or even substances with high pharmacological concentration (such as anesthetics or hyperosmolar solutions), waste is generated that must be treated as biohazardous, infectious or chemical waste. These wastes, if not properly managed, represent a high risk to staff, patients, the environment and may constitute a legal non-compliance.
The management of these wastes begins with the design of the facility. The plant must have a specific area for the handling, classification, temporary storage and removal of waste. This area should be physically separated from the preparation area to avoid cross-contamination. In addition, it should be easily accessible to removal teams, but restricted to unauthorized personnel.
There are several types of waste generated in a blending plant, and each requires a particular treatment:
Cytotoxic and antineoplastic wastes, including partially used vials, syringes, needles, empty vials, contaminated infusion bags and cleaning materials (towels, gloves, gowns) that have had contact with these compounds. These should be placed immediately after use in rigid, airtight, puncture-resistant containers, marked with the cytotoxic symbol and managed as special hazardous waste according to local legislation or standards such as NTP 905, OSHA or PAHO's Manual of Good Handling Practices for Cytotoxics.
Contaminated liquid wastes, such as spills of drug solutions, are collected using specific absorbent kits and are also disposed of as hazardous waste. They should not be discharged into common drains, as they contaminate the water system and can affect sensitive organisms even at minimal concentrations.
Used HEPA filters, personal protective equipment (PPE) and other maintenance waste, if they have been in contact with hazardous drugs, should be considered as chemical or infectious waste depending on the exposure context.
All personnel working at the plant must be specifically trained in the safe handling of hazardous waste. This includes knowing the types of waste, the protective equipment needed to handle them, the maximum time they can remain in the temporary storage area, and the protocols in case of spills or accidents.
It is essential to have a spill contingency plan. This includes the availability of spill kits at strategic points in the plant, which should contain thick nitrile gloves, a mask, eye protection, an impermeable gown, hazardous waste bags, absorbent material and rigid containers. Personnel should know how to act quickly and follow a procedure sheet validated by the hospital biosafety committee.
Final disposal is carried out by certified waste management companies that transport the waste under safety standards and destroy it through processes such as high-temperature incineration or alternative technologies such as plasma treatment or encapsulation. These companies must provide certificates of final disposal, which are part of the documentation required in sanitary and environmental audits. Finally, it is necessary to establish a periodic evaluation of the waste management program, including internal audits, analysis of nonconformities, review of incidents and drills. The central mixing plant should be an environment of continuous improvement, where biosafety is managed with the same rigor required for pharmaceutical quality.
Biosafety and traceability are fundamental issues, the construction of a mixing plant cannot be left to chance or rely on improvised solutions. A highly specialized technical intervention is required, capable of integrating not only a high-level physical infrastructure, but also the intelligent systems and equipment necessary to ensure that each pharmacological mixture is carried out under the strictest conditions of environmental control, safety and quality.
At INPAL, we are dedicated to design, build and implement state-of-the-art hospital compounding plants, based on international standards such as ISO 14644, USP <797> and <800>, and with a deep understanding of the hospital pharmaceutical operational flow. Beyond the civil or architectural work, our focus is on the functional engineering of the environment, and the integration of specialized technology that guarantees sterile, safe and traceable spaces from the first day of operation.
We implement highly automated systems, with differential pressure control between areas, terminal HEPA filtration, real-time environmental monitoring and centralized digital management. This allows us to maintain the appropriate cleanroom classification in each zone (ISO 7, ISO 8, and ISO 5 in cabins), actively minimizing the presence of particulate and microbiological contaminants. We incorporate distributed sensors, motorized valves, automated airlock doors and warning systems that guarantee an environment always within safe parameters.
In addition, we integrate laminar flow cabinets, class II B2 biological safety cabinets, weighing cabinets and aseptic workstations, all connected to an intelligent monitoring network that allows the hospital to have full visibility of operating conditions, record every step of the process and react in real time to any deviation.
In a hospital where the patient's life literally depends on every milliliter prepared under sterile conditions, our job is to build spaces that not only comply with the norm, but also exceed the standards and become a benchmark for safety, efficiency and technology applied to healthcare.

Tel: +52 55-1114-8980
Wa: +52 55 8255 8084
Comments