[vc_row full_width=”stretch_row_content_no_spaces” css=”.vc_custom_1564595752256{padding-top: 300px !important;padding-bottom: 220px !important;background-image: url(http://br306.teste.website/~ferra863/steq/wp-content/uploads/2019/07/I-Holland-Tooling-1480x650black.png?id=1035) !important;}”][vc_column][vc_column_text]
How can formulation affect tooling?
[/vc_column_text][vc_separator color=”sandy_brown” border_width=”3″ el_width=”10″][/vc_column][/vc_row][vc_row css=”.vc_custom_1564073259210{margin-top: 25px !important;margin-bottom: 25px !important;}”][vc_column width=”3/4″][vc_column_text]The development of a solid oral dosing formulation, which can be compressed into a modern high-speed press, demands a large number of technical challenges. Many of them refer to the physical content of the formulation to be used, from moisture content to abrasiveness. The tooling used for compression needs to reflect these formulations to ensure a final product free of quality flaws. Tooling and related equipment should be chosen according to the formula being used and proper tooling maintenance and customary operating procedures should be adhered to, with the aim of reducing the many variables that affect tablet production. In this text we will address the most common problems with the composition of the formulation and how they affect its production.
Particles
The first question to be considered is whether the formulation to be used contains very small particles. If this happens, then the gap between the punch tip and the die is critical. If the gap is too large, then the smallest particles in the formulation can pass between the punch and the die. This can cause a number of problems, including sticking and mismatch in the fit between the punch tip and the die. This, in turn, generates friction and heat responsible for causing abrasion of both the die and the tip of the punch, resulting in an irregular compression on the circumference of the tablet. Fine particles can also pass through the seals of the bottom punch guide. If these measurements are not sufficiently adjusted or worn, even more stress and wear can be generated between the punch body and the lower guides. The particles can also cause a general contamination problem as they spread more easily through the air, penetrating the top guides and causing similar damage when accordion seals and retainers are not used and maintained correctly. Excess particles will result in poor quality tablets, adherent tooling and overheated press, which increases tablet adhesion and deformation problems.
Moisture
The moisture inside a tablet is often necessary to help with the “stickiness effect,” but it can also be the cause of warping. When the adhesive forces from the formulation to the punch tips exceed the cohesive forces inside the tablet, deformation can occur. The water inside the tablet can be one of the causes of an increase in adhesion strengths. This happens by increasing the capillary action between the surface of the tooling assembly and the granule. Capillary bridges form causing areas of high adhesion, thus creating adhesion. Moisture can enter during the wet granulation process or into the compression chamber when the area is not environmentally controlled: the latter can even directly affect formulations. One solution would be to use non-stick coatings applied to the tooling, which repel rather than attract moisture. However, selecting the right coating for the job is done by an expert that not all tooling manufacturers have. When coatings are developed correctly and their beneficial characteristics are compared to those of the formulation, they can help increase corrosion resistance, wear resistance and prevent formulations that adhere to punch tip faces. Traditionally, the most popular coating used within the global tooling industry is hard chrome, due to its low-cost and general-purpose characteristics in terms of its median non-stick, anti-corrosive and anti-wear properties. However, there are plenty of options out there: one of the latest additions to the I Holland portfolio is the PharmaCote® CT (textured chromium nitrate). This unique surface treatment, combined with the PharmaCote® CN non-stick coating, generates a non-stick tip face, as well as exhibiting corrosion and wear resistance.
Abrasive
Some formulations contain ingredients that are particularly hard and sharp. Typically (but not exclusively), these are found in nutraceutical products that contain many hard minerals and organics. Through repeated cyclic compression, these abrasive ingredients can wear away both the surface of the punch tip and the matrix, resulting in low-quality tablets. Under high compressive forces, hard granules can still impregnate the surface of the punch tip. These actions can lead to other tablet problems, such as capping, delamination, or stickiness. This abrasive action can be countered by the use of advanced material tooling and coatings selected for their wear resistance properties. Materials such as I Holland’s specialized steels, used in conjunction with resilient coatings such as Pharmacoat RS or tungsten carbide, have high hardness values and specific structures that wear at a much lower rate. In some cases, tooling life has been increased by 700% over tooling constructed of standard steel.
Corrosive
Certain components of the formulation may contain corrosive elements, such as chlorine, salts, and acids that will react with tooling surfaces, resulting in oxidation. In addition, the WIP systems installed in some modern compressors expose the tooling to water and cleaning solutions, thus requiring that the tooling has more corrosion-resistant properties. In fact, post-compression cleaning procedures can also cause corrosion if not controlled efficiently. Corrosion can appear as discoloration, wear or as common red rust. To combat this problem, a corrosion-resistant material can be selected, however, some grades of stainless steel are not suitable due to the lack of hardness and wear resistance. Therefore, martensitic stainless steels with high chromium content should be used. It is also possible to apply hard coatings with corrosion-resistant properties, such as hard chromium or chromium nitrite.
Deformation characteristics
The characteristics of certain ingredients in a formulation may have plastic or elastic properties that lead to formation problems such as adhesion and capping. If the behavior of a particle under compression causes a deformation or the “spring back” effect in its original shape, machine downtime can be critical. In cases of formulations where the consolidation behavior depends on more time, a long dwell time is important to create strong bonds between the particles. In a situation where a longer downtime may be required, there are tooling on the market to help, including the new I Holland tooling: the innovative flat protractor (XDF) will allow for adequate compression dwell time for a formulation without the inconvenience of delaying the press.
Crispiness
The friability, or the tendency to crack, laminate or break during compression occurs, in part, due to the formulation. If the formulation is not cohesive and does not bond sufficiently, friability will occur. There are several ways to compensate for friability, including managing dwell time, weight control, expansion, and of course, the condition of the tooling. All of these factors must be examined to produce a quality tablet.
How to produce a flaw-free tablet?
Developing formulations for solid-dose products can be a complex and problematic procedure, however, with the application of certain considerations and measures, this can be successfully achieved. Typically, pharmaceutical formulations contain one to four active agents and five to six excipients. This can bring challenges related to particle size, flow, compression, interaction, content, and uniformity. For example, some active ingredients may be available in granular form, while others may only be available in fine powder form; some may be hydrophilic, others hydrophobic. For this reason, the mixture can have different particle sizes and ingredients with a variety of characteristics. When under compression, some formulations can cause adverse effects such as abrasion, wear or corrosion on the puncture tips. Although tooling is manufactured from hardened and hardened steel, the demanding processes involved can lead to rapid deterioration if the tooling material is not optimized to meet the formulation. Some granules are extremely hard and abrasive and can scratch, wear and impregnate the surface of the steel. Other granules may contain corrosive elements that react with steel. These effects can be reduced by understanding the nature of the formulation and carefully selecting the material or coating of the tooling. Therefore, we conclude that it is important to speak with an experienced tooling supplier if you encounter manufacturing problems, as they will know to pinpoint exactly what the problems are and offer a solution. The customer, in turn, will be able to reduce their costs through continuous production. Nowadays, in order to produce consistent mass tablets with tailor-made properties, all processes must be considered, which includes the formulation to be used.
By Rob Blanchard
, R&D Manager, I Holland[/vc_column_text][/vc_column][vc_column width=”1/4″][vc_basic_grid post_type=”post” max_items=”3″ element_width=”12″ gap=”15″ item=”958″ grid_id=”vc_gid:1580394121179-1b549629-3b94-8″ taxonomies=”4, 1, 5, 3″][/vc_column][/vc_row]
