What is an autoclave in pharmaceutical industry

Let’s discuss autoclave in pharmaceutical industry, their applications, working principle, and the autoclave cycle.


An autoclave in pharmaceutical industry is a machine that kills microorganisms in the pharma sterile production process under steam. It sterilizes different items from dangerous microorganisms and contaminants that can become harmful to a pharmaceutical product.

Autoclave uses steam in an enclosed air-tight chamber to kill these harmful elements. The air-tight chamber is capable of bearing high temperatures and pressure of steam. Autoclaves can sterilize components such as glassware, clothes worn by personnel working in a sterile area, and filled products.

The autoclave achieves high temperatures due to the direct relationship between pressure and temperature i.e. higher the pressure higher the temperature, and vice versa. The steam is applied under pressure until the chamber achieves the required temperature. The sterilization temperature is variable and depends on many products, contaminants, and process requirements. 

Autcalves are also provided with recording devices, capable of automatically recording process parameters at regular frequency.

What is an autoclave in pharmaceutical industry used for?

Sterile products in the pharmaceutical industry are critical to human health, and any harmful item or contamination can adversely affect the patient’s life. Because sterile products come in direct contact with skin or internal organs. For this purpose, autoclave in pharmaceutical industry are used for sterile items that come in direct contact and to manufacture sterile products. 

Some common items for which an autoclave can be used are mentioned below


Various types of glassware are common in sterile product manufacturing. One common type is a Glass jar, used in batch manufacturing to react chemical compounds. There are different capacities of glassware, such as 5 and 10 liters.

Glass tubing is also an example of glassware to connect different components, such as filling machines and filtration assembly. 

Stainless Steel items

Stainless steel items are also an integral part of sterile product manufacturing. Examples include filtration assembly and its associated components. Stainless steel can easily bear the autoclave’s high temperature and responds satisfactorily to steam sterilization.

Wearable items

Wearable items such as dangri suits by the personnel involved in the manufacturing process. These wearable items must be sterilized after completion of the production cycle. 

These wearable items are made up of material that can easily sustain the high temperature and steam pressure of autoclaves

Plastic items

Plastic items such as tubing or other machine parts come directly with the product before or during filling. When each manufacturing cycle is completed, they must be sterilized. 

Some containers, such as Vials, require plastic seals to enclose the container after filling. In that case, seals are also sterilized before being used for sealing purposes.

Product Filled Containers

When filling is completed in the containers, such as the Vials or ampoules, they are autoclaved for sterilization. This is called terminal sterilization, and like other items, sterilization parameters depend on the product characteristics inside a container.

What is the working principle of autoclave in pharmaceutical industry?

The main working principle of autoclave in pharmaceutical industry is Microbial Lethality. It indicates a heating process’s effectiveness in inactivating, killing, and removing microorganisms.

The time required to achieve microbial lethality reduces if autoclaving temperature increases.   – at low temperatures, more time is required, and vice versa.

To achieve the required microbial lethality, the below characteristics of steam are required.

autoclave in pharmaceutical industry


What is the cycle of autoclave in pharmaceutical industry?

The complete cycle of autoclave in pharmaceutical industry is divided into stages to achieve the desired temperature and pressure.

A successful autoclave cycle consists of many individual small steps. If there is any fault or error in these small steps, the end result of the autoclave is unsatisfactory and will fail to achieve sterilization.

Typically, an autoclave cycle consists of following individual steps

Pre–Vacuum Stage

In this stage, a vacuum is created inside the autoclave chamber before allowing steam to enter. After achieving the desired vacuum value, the chamber is filled with steam to break the vacuum. This process of achieving and breaking the vacuum is executed more than once. The purpose of the pre-vacuum stage is to 


Sterilization Stage

 In this stage, steam enters the chamber until the required temperature and pressure are achieved. When both these parameters are achieved, the sterilization phase starts. A user-defined timer is activated to maintain the required temperature and pressure for a specified time period. 

After the sterilization timer elapses, the autoclave automatically switches to the next and final stage.

Post–Vacuum Stage:

This stage is activated after the sterilization timer elapses. The vacuum pump is used to remove all the steam inside the chamber. The removal of steam helps cool of chamber and normalize chamber pressure. The post-vacuum cycle also helps to dry items, as steam often creates moisture at low temperatures.

What is the relationship between the Pressure and Temperature of autoclave in pharmaceutical industry?

Autoclave temperature is directly proportional to the steam pressure. If we inject steam in an autoclave chamber with higher pressure, it can achieve higher temperatures. Similarly, low temperatures are achieved if we inject steam in an autoclave with lower pressure.

This relationship is defined by Gay-Lussac law. This law states that the temperature of a gas is directly proportional to its pressure. In other words, increasing the pressure helps to increase the stem’s temperature. This higher-temperature steam can be used for different applications in many industries.

Relationship between Autoclave Pressure and Temperature


The pressure of steam needs to be increased because saturated steam used in autoclave exists at 100°C. To use autoclaves for greater temperatures, steam pressure is increased. Increasing steam pressure allows the autoclave to be used for applications requiring temperatures more than 100°C, and it is difficult to achieve higher temperatures with low steam pressure.

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