Glovebox Workstation：Principles and working of Glovebox

What is Glovebox Workstation?

Containment in the pharma industry has been the biggest concern for pharma professionals and is forcing the industry to develop new concepts and designs. Additionally, more robust, customizable, and controllable operations should be developed, given the changing dynamics of the pharma industry.

The glove box is a technology used in the pharma industry to enhance containment during critical processes, in addition to existing containment solutions such as HVAC and clean rooms. It can be used to provide excellent containment for a variety of pharma applications. It offers more flexibility and control over traditional containment options.

The best part of the glove box is that it can be integrated into existing processes, where required, without changing the process life cycle.

What is a glovebox?

A glovebox is an enclosure with built-in gloves on its walls at the side of working area. It is critically designed to cater for the process, and is completely separated from the rest of the environment, room or other methods.  It allows personnel to wear them to carry out routine production, manufacturing, and testing processes.

The operator or user inserts their hand in the gloves and performs the required tasks. It also includes a transparent sheet allowing the operator to see inside the glove box. Electronics and electrical controls are also integrated to control various parameters and ensure smooth operation.

Glovebox workstations are used for applications that require complete isolation from the entire environment and the operator. For example, when protecting a sample from contaminants or from itself due to the toxic nature of products (or raw materials). It allows the pharma industry to provide necessary protection parameters instead of arranging for an entire area or room.

Inside a glovebox, it is also possible to maintain specific environmental conditions, i.e. temperature and humidity, that best suit the product or process being carried out.

It is also possible for glove boxes to mount on fixed equipment, such as an injectable filling machine.  After completion of the process, the glove box can be demounted from the process equipment for various purposes, such as cleaning

Configuration

There are two standard configurations of glove boxes in which it is operated – under vacuum and positive pressure.

In a vacuum configuration, a vacuum is created inside a chamber that continuously maintains a negative pressure. The purpose of this configuration is to protect operators from toxic air, toxic gases and chemical fumes, by preventing them from going out of the chamber. This configuration is used for harmful and hazardous materials.

In a positive pressure configuration, positive pressure is maintained inside the chamber. It flows the inside fluids into the area of operation, process or production. Its purpose is to protect the items inside, and it is applied for non–toxic and non-hazardous materials.

Parts of the glove box

Some common parts of pharma glove boxes include but are not limited to, the following.

Chamber

The chamber is the main enclosure where the working area is installed. The gloves are placed at the chamber’s side in a way that can easily access the entire working area. It is an area where operators perform all the relevant tasks and processes.

The chamber is sealed air-tight to prevent contamination with the outside environment, foreign bodies or microorganisms. Fluid flow across the chamber is also monitored through appropriate monitoring sensors.

During operation, all process equipment, accessories, instruments and other tools are placed inside the chamber.  The size of the chamber depends on the capacity of the glove box.

Gloves

Gloves are attached to one wall of the chamber through airtight ports. They are used by the operators from the outside to manipulate and handle things inside. They are made of rubber, suitable for products, processes, and items dedicated to the pharmaceutical industry. Additionally, these gloves should offer comfort for operators to prevent any operator difficulty.

These gloves are manufactured in a single piece design or glove/sleeve design, and operators can insert their hands past their shoulders, offering more flexibility in their routine tasks.

Transfer mechanism

During operation, it is expected that materials are frequently transferred in and out of the glove box for various purposes. In the glove box, it occurs through the Antechamber.

Antechambers are small attachments to the glove box that can be used to transfer material in and out of the glove box without disturbing the internal environment’s operational and purity parameters.

The Antechamber is interlocked with the chamber so that both openings of the Antechamber cannot be operated simultaneously.

To transfer material into the chamber, the Antechamber is first evacuated from the existing air or gas. After evacuation, materials are placed in the Antechamber, and inert gas or chamber gas is filled in. Depending on the application and machine, this process can occur multiple times, which is decided during validation studies.

The materials are then offloaded inside the glove box through the inside door.

Miscellaneous Parts

In addition to the main parts mentioned above, there are also some miscellaneous parts. The inclusion of these parts depends on the machine model and application requirement and can include, but is not limited to：

Electrical Parts–control panel, controller and sensors to operate and regulate the glovebox operation.

Filters– These include HEPA or ULPA, which are used to filter the air inside the glove box. Their specifications depend on the area of installation and application requirements.

Vacuum pump–to create a vacuum and remove air inside the Antechamber.

Valves–they are used to start and stop the fluid flow in different sections of the glove box, as per the application requirements.

Gauges are manual devices that indicate the pressure inside critical components such as the chamber and Antechamber. They are mainly used as a visual tool for operators to monitor the process. They are also helpful in tracking the process in the event of a power breakdown.

Principles and working of Glovebox

Principle

Its main principle is to carry particles from the chamber to maintain the purity required levels.

During continuous circulation, it carries away any water, foreign particles, and other gases. The carryover particles are collected in a purification chamber. 

Working

The working of the glove box can be described as follows：

• Before operating a glove box, make sure all the desired connections, such as electrical supply and compressed air, are made.

• Pay special attention to all the air-tight seals used in the extended accessories & parts in the Glovebox, such as transfer ports and gloves.

• Make sure the entire glove box is assembled correctly and has all of its necessities, such as seals, attachments, piping, and connections.

• Power - up the machine and wait for the electrical panel to activate and stabilize.

• Before starting the glove box, fill the chamber with the inert gas to remove any foreign particles and contaminants.

• Set all the operational parameters. Refer to the SOP or the operational manual.

• Transfer materials to the Antechamber and close it tightly. The items in the Antechamber will be flushed with inert gas (or other suitable gas) for a fixed time and a number of cycles. Its purpose is to purify and clean the items and make them ideal for glove boxes.

• After completion of the flushing cycle in the Antechamber, open the inside window or door      of the Antechamber.

• Transfer all items into the glove box.

• The items can remain in the Glovebox, provided the environmental parameters stay within the limits.

• The purification inside the chamber is ensured through purifier, which can reach its threshold.

• If the limit of purifier reaches the threshold limit, the purifier is regenerated.

• Purifier regeneration is performed automatically, without disturbing the items inside the glove box.

• After process completion, and if the glove box is not required further, the system is powered off. Refer to the SOP or manufacturer’s instruction for safely shutting down the system.

Advantages of Glovebox

Glove boxes in the pharma industry can be attributed to the following advantages.

Safe handling of toxic materials

Glove boxes can be used to safely handle toxic materials used in pharma product development and manufacturing. It prevents direct interaction with these materials, whereby providing the same level of control during the process.

The raw material of every pharma drug product can be dangerous to human health if consumed directly. Especially for some pharma drug products, such as antibiotics, their raw materials are toxic. Glove boxes contain these raw materials in an enclosed chamber, providing operators the flexibility to manipulate things inside it.

Customizable enclosure for drug handling

Glove boxes provide customizable options for controlling different environmental parameters. Rather than constructing a dedicated facility or area for a small process, it allows the pharma industry to control parameters according to the product or process requirement in a small area.

For example, weighing and dispensing is a critical process where raw materials are weighed before being dispensed. The weighing and dispensing must be performed in a controlled area to prevent altering the raw material’s properties. Glove boxes provide an opportunity to perform weighing using their required controlled parameters instead of constructing and developing a dedicated area for this purpose.