Pharmaceutical engineers requiring to mix wet and dry powders and dry blends during pharmaceutical manufacture have traditionally relied on batch mixing. To improve efficiency, reduce costs and address inconsistencies in batch production, pharmaceutical manufacturers are beginning to use continuous mixing, a process more commonly found in food manufacture, to improve pharmaceutical powder processing, reports Dr Eddie McGee, technical director, Ajax Equipment Ltd.
Batch mixing is traditionally used for the manufacture of the active pharmaceutical ingredients (APIs) and subsequent post-processing. However, this process has various drawbacks compared with continuous operation, being particularly prone to inconsistencies between batches caused by powder segregation during processing, changes in temperature, humidity, powder particle size and storage. It also tends to be labour intensive and introduces problems of flow, residue, stock handling and the matching of output with filling and packing operations. Moreover, any problems that may be found in batches are only detectable after the mixing process has been completed, which is then time consuming and expensive to correct.
Pharmaceutical companies have previously rejected change to continuous operation because of the demanding requirements of the industry for quality control and verification. With recent improvements in on-line measuring techniques and control technology, however, users are now employing continuous mixing as an alternative to batch mixing in some production situations. Continuous mixing allows process engineers to side step many of the problems encountered in batch processing. Powders are mixed as they move along the short casing of the machine.
Using new monitoring techniques within the mixer, pharmaceutical manufacturers are now able to check the composition of the mixed powders as the product is produced. The engineer has greater control over the degree and quality of mixing by on-line monitoring the mixed product as it moves along the continuous mixer. This avoids any inconsistency, such as may occur between or within batches and the need to rework materials – material being analysed and verified as it is produced. It is this ability to analyse the composition of powders in 'real time' that has allowed pharmaceutical manufacturers to introduce continuous mixing as a practical alternative to batch processing.
In general continuous mixers are capable of introducing differing degrees of work content to the mixing operation by using either single or twin mixing shaft arrangements. The choice will depend on the powder composition and amount of mixing needed to achieve efficient dispersion to produce the final product. Compared with batch mixers, by working on the material at a smaller scale paddle and ribbon screw geometries in continuous mixers allow greater control, and more efficient mixing with negligible damage to powders.
The choice of mixing element geometry can be used to provide a more intensive mixing action, while the open form and geometry of the ribbon screw is ideal for gentle mixing. Special forms of mixing flight construction are designed to inhibit the build up of sticky compounds, while making cleaning easier. The flexibility of the continuous mixer is further facilitated by the use of interchangeable mixing shafts, allowing the machine to be used for a wide range of pharmaceutical compounds.
The relatively small size and flexibility of continuous mixers makes it easy to fit them into the pharmaceutical production process. Screw feeders are generally used to deliver ingredients in a controlled manner into the mixer. Liquor additions can be made by way of sprays or drizzles, as appropriate. Moreover, the mixer body and / or the mixing augers can be temperature controlled, either heating or cooling product as required, in a way that is much more difficult with batch mixers. To meet the strict hygiene standards found in the pharmaceutical industry, continuous mixers are fitted with quick release screw shafts and end plates or may have a clean-in-place option. These allow the screws to be quickly removed for cleaning and product changeover or to change between the different mixing forms.
The use of continuous mixing for producing pharmaceutical products is somewhat of a watershed in the industry. It transforms manufacture from a disconnected, sequential operation involving intermediate storage, intermittent sampling and assessment and separate product quantities to a compact, continuous flow line with minimum manual intervention and laboratory testing. The technique that has proved so successful in foodstuffs, confectionery and many other industries is now available for exploitation in the pharmaceutical industry.
For further information on continuous mixers and the issues raised in this article, contact Dr Eddie McGee, technical director, Ajax Equipment on 01204 386723.
Continuous Mixing of Pharma Powders
Continuous Mixing for Pharmaceutical Processing
Pharmaceutical engineers requiring to mix wet and dry powders and dry blends during pharmaceutical manufacture have traditionally relied on batch mixing. To improve efficiency, reduce costs and address inconsistencies in batch production, pharmaceutical manufacturers are beginning to use continuous mixing, a process more commonly found in food manufacture, to improve pharmaceutical powder processing, reports Dr Eddie McGee, technical director, Ajax Equipment Ltd.
Batch mixing is traditionally used for the manufacture of the active pharmaceutical ingredients (APIs) and subsequent post-processing. However, this process has various drawbacks compared with continuous operation, being particularly prone to inconsistencies between batches caused by powder segregation during processing, changes in temperature, humidity, powder particle size and storage. It also tends to be labour intensive and introduces problems of flow, residue, stock handling and the matching of output with filling and packing operations. Moreover, any problems that may be found in batches are only detectable after the mixing process has been completed, which is then time consuming and expensive to correct.
Pharmaceutical companies have previously rejected change to continuous operation because of the demanding requirements of the industry for quality control and verification. With recent improvements in on-line measuring techniques and control technology, however, users are now employing continuous mixing as an alternative to batch mixing in some production situations. Continuous mixing allows process engineers to side step many of the problems encountered in batch processing. Powders are mixed as they move along the short casing of the machine.
Using new monitoring techniques within the mixer, pharmaceutical manufacturers are now able to check the composition of the mixed powders as the product is produced. The engineer has greater control over the degree and quality of mixing by on-line monitoring the mixed product as it moves along the continuous mixer. This avoids any inconsistency, such as may occur between or within batches and the need to rework materials – material being analysed and verified as it is produced. It is this ability to analyse the composition of powders in 'real time' that has allowed pharmaceutical manufacturers to introduce continuous mixing as a practical alternative to batch processing.
In general continuous mixers are capable of introducing differing degrees of work content to the mixing operation by using either single or twin mixing shaft arrangements. The choice will depend on the powder composition and amount of mixing needed to achieve efficient dispersion to produce the final product. Compared with batch mixers, by working on the material at a smaller scale paddle and ribbon screw geometries in continuous mixers allow greater control, and more efficient mixing with negligible damage to powders.
The choice of mixing element geometry can be used to provide a more intensive mixing action, while the open form and geometry of the ribbon screw is ideal for gentle mixing. Special forms of mixing flight construction are designed to inhibit the build up of sticky compounds, while making cleaning easier. The flexibility of the continuous mixer is further facilitated by the use of interchangeable mixing shafts, allowing the machine to be used for a wide range of pharmaceutical compounds.
The relatively small size and flexibility of continuous mixers makes it easy to fit them into the pharmaceutical production process. Screw feeders are generally used to deliver ingredients in a controlled manner into the mixer. Liquor additions can be made by way of sprays or drizzles, as appropriate. Moreover, the mixer body and / or the mixing augers can be temperature controlled, either heating or cooling product as required, in a way that is much more difficult with batch mixers. To meet the strict hygiene standards found in the pharmaceutical industry, continuous mixers are fitted with quick release screw shafts and end plates or may have a clean-in-place option. These allow the screws to be quickly removed for cleaning and product changeover or to change between the different mixing forms.
The use of continuous mixing for producing pharmaceutical products is somewhat of a watershed in the industry. It transforms manufacture from a disconnected, sequential operation involving intermediate storage, intermittent sampling and assessment and separate product quantities to a compact, continuous flow line with minimum manual intervention and laboratory testing. The technique that has proved so successful in foodstuffs, confectionery and many other industries is now available for exploitation in the pharmaceutical industry.
For further information on continuous mixers and the issues raised in this article, contact Dr Eddie McGee, technical director, Ajax Equipment on 01204 386723.
For more information, please visit:
https://edir.bulk-online.com/profile...-equipment.htm1083 ajax equipment.htm
http://www.google.com/search?hl=de&c...btnG=Suche&lr=search?hl=de&client=safari&rls=de de&q=ajax+site%3Abulk online.com&btnG=Suche&lr=
Additional information:
http://www.google.com/search?hl=de&c...btnG=Suche&lr=search?hl=de&client=safari&rls=de de&q=continuous+mixing+site%3Abulk online.com&btnG=Suche&lr= ■