An active ingredient (AI) is the ingredient in a pharmaceutical drug that is biologically active. Similarly active pharmaceutical ingredients (API's) and bulk active are also used in medicine, and the term active substance may be used for natural products.

Active Pharmaceutical Ingredient (API) manufacturing involves batch reaction, work-up, layer separation, filtration, distillation and drying as unit processes. Again, batch reaction involves heating and cooling stages ranging from -40 to +150 deg C. Conventionally, this is done with multiple utilities such as chilled brine, chilled water, cooling water, hot water, low pressure steam and high pressure steam etc.

However, this approach has the many major disadvantages:

• More utility header lines required near operating area
• Cross contamination of utility fluids
• Utility changeover by operator
• During change over, utilities are wasted if drained due to mix-up
• Condensate recovery is not feasible
• It may cause thermal shocks due to sudden change in temperature, if gradual change over is not practised
• Accurate temperature control is not possible
• Increases overall cost

Many API processes have temperature as a critical control point and hence accurate temperature control is essential. This is a significant parameter to be considered while designing multi-product facility or a kilo lab, which is used for carrying out validation batches for the main plant.

While heating to temperature above 150°C and cooling after the reaction is critical – the use of cooling water will lead to formation of steam in the jacket – and thus over pressurisation besides the thermal shock. Due to these factors, single fluid heat transfer systems (SFHTS's) have gained importance in pharmaceutical and chemical Industries and their many operational advantages are offering forward thinking process plants significant competitive advantage.

Today, plants are increasingly looking to attain competitive advantage; something that differentiates them in the market place. Often product pricing is of strategic importance in this regard and this, in the main, is driven by the plant's operational performance efficiency.

Forward thinking plant engineers and managers are increasingly looking towards Single Fluid Heat Transfer Systems to help manage operations in bulk drug processing, batch reaction, distillation, crystallisation, hydrogenation and drying.

There are many advantages of these systems including;

• Easy to maintain.
• Cleaner operation.
• Precise temperature control.
• No leakage at process area – it helps in maintaining a neat and clean plant.
• The operation is corrosion free.
• Centralised control.
• No cross contamination of utilities.
• No hot and cold spots – this in turn results in consistent product yields and quality – a regulatory requirement for APIs.
• Piping network is more aesthetic.

and when used with stainless steel reactors or glass lined reactors, the advantages are;

• No thermal shocks to reactor.
• No steam traps at reactor.

However, the selection of heat transfer fluid and system is critical and that's where companies like Stanseals' technical expertise comes into play.

The client (or user of the system) typically specifies the operating temperature range of their equipment and their desired heat transfer rate and Sunrax do the rest, designing, manufacturing, installing and commissioning the single fluid heat transfer system to suit the user specification. Contact Stanseals for further information