Accessory for universal traction machine

Description

10 ACCESSORY FOR UNIVERSAL TRACTION MACHINE FIELD OF THE INVENTION

[001] The present invention is situated in the field of supports for performing tensile tests on universal testing machines with the aim of evaluating the adhesion properties of multilayer tablets. The difficulty in obtaining data on the mechanical adhesion properties between tablet layers directly compromises the quality and performance of medicines, negatively impacting the effectiveness of treatments. This accessory for a universal testing machine offers a new arrangement capable of solving the problems inherent in taking tensile measurements on a universal testing machine. FUNDAMENTALS OF THE INVENTION

[002] Currently, in the field of mechanical property analysis of multilayer pharmaceutical tablets, there is a lack of standardized methods and specific clamps in mechanical testing machines to directly assess the adhesion between tablet layers, making it difficult to obtain crucial data on the structural integrity of the pharmaceutical product. Existing accessories do not allow for the fixation of the test specimen, making any type of analysis impossible. Furthermore, no other analytical equipment is capable of evaluating this type of property.

[003] As a result, the lack of detailed information on the mechanical properties of adhesion compromises the optimization of tablet formulation and production, affecting the quality and performance of the medicines. The difficulties related to adapting smaller specimens for mechanical testing are already known, with the main challenge being adaptation. Petition 870250012561, dated 02 / 15 / 2025, page 11 / 80 / 10 of universal systems for the evaluation of mechanical properties of tablets.

[004] In this context, the present invention describes a new way of using a universal testing machine through the use of an innovative accessory, developed by 3D printing using the fused deposition modeling (FDM) technique. This accessory was specifically designed for performing tensile tests on tablets, allowing the secure fixation of samples in the equipment and the application of axial force in a controlled and precise manner. The use of this customized accessory proves to be fundamental for evaluating the adhesion between the layers of tablets, providing reliable and reproducible results that contribute significantly to the quality control of these pharmaceutical products.

[005] For tensile testing equipment and universal mechanical analyzers, there are some standards proposed by the American Society for Testing and Materials (ASTM) that determine how certain tests should be conducted. Among all the standards described, those that most closely resemble the purpose of evaluating adhesion between multilayer tablets are the D7522 / D7522M-21, D3330 / D3330M-04 and D3359-23 tests.

[006] The D7522 / D7522M-21 standard establishes a test method for determining the pull-out resistance of fiber-reinforced polymer laminate systems when bonded to concrete substrates. In this method, a bonding adhesive is used to attach the concrete slab to the grip of the equipment, which applies an axial force opposing the specimen, measuring the force required to separate the polymer from the concrete. This test is only feasible for large samples, as the load cell must have a minimum diameter of 50 mm and withstand a high level of force (ASTM D7522 / D7522M-21, 2021). Thus, both the apparatus Petition 870250012561, dated 02 / 15 / 2025, page 12 / 80 / 10, regarding the testing methodology, does not allow the analysis of a tablet, which is a very small and fragile test specimen.

[007] The D3330 / D3330M-04 standard refers to a test method for measuring the adhesion of pressure-sensitive adhesive tapes. In this methodology, the adhesive tape is fixed to a surface that is at a 90° or 180° angle to the gripper, which applies a force in the opposite direction, with the aim of breaking the adhesion created by the tape (ASTM D3330 / D3330M-04, 2018). This test does not allow for the evaluation of adhesion between layers of a tablet since the fixing surface does not allow for the clamping of this test specimen and the gripper does not allow for its pulling.

[008] Finally, the D3359-23 standard describes standardized methods for evaluating the adhesion of coatings to substrates through adhesive tape tests. To perform this test, several coating samples, such as paints and varnishes, are applied to metallic or plastic surfaces. Subsequently, several standardized cuts are made in this surface, and adhesive tape is positioned over the cuts and then removed to evaluate the adhesion (ASTM D3359-23, 2023). Like other tests standardized by ASTM standards, this protocol is also unfeasible for studying the adhesion between layers of tablets, as it does not allow the specimen to be fixed, and the cutting methodology is not consistent with the purpose proposed by the invention presented here.

[009] In the current state of the art, problems related to adhesion testing are commonly solved by using commercially available adhesion testing machines. However, this solution generally applies to adhesion testing of adhesive tapes, engravings on various materials, and coatings. Additionally, there are no correctly sized tablet holders and adapters on the market, which Petition 870250012561, dated 15 / 02 / 2025, page 13 / 80 / 10, allows the use of universal mechanical testing machines for adhesion testing on tablets.

[010] Although there is no standardized method for layer separation experiments, some inventions have been proposed in scientific articles, such as the evaluation of the separation of bilayer tablets using a customized shear test apparatus. This test is performed in a compaction simulator, in which the tablet is first fixed perpendicularly to the surface of the equipment and the first layer of the tablet is exposed to the upper punch of the device. The shear force is applied by the upper punch to the interface between the tablet layers to measure the resistance to delamination. During the test, the device records the force required to cause delamination between two layers of a tablet (BELLINI et al., 2019).

[011] Still focusing on bilayer tablets, another test was customized to evaluate the interfacial resistance between the two layers of a tablet. This protocol involves using a prototype micro press to apply a load to the bilayer tablets, which in turn are placed on a V-support and tensioned with a punch. The breaking strength is then determined as the separation force required to separate the two layers of the tablet and serves as a measure of the interfacial mechanical adhesion of the bilayer tablets (BUSIGNIES et al., 2014).

[012] Another work available in the literature describes a semi-automatic apparatus designed specifically for bilayer tablets. In this customized apparatus, the upper part of the tablet is fixed to one of the grips with the aid of glue, and the lower part is fixed in the same way to the other grip. Subsequently, an axial force is applied to the test specimen by Petition 870250012561, dated 02 / 15 / 2025, page 14 / 80 / 10 both grips promoting the separation of the layers and quantifying the interface resistance (AKJSELI et al., 2013).

[013] All these adapted protocols can only be performed on bilayer tablets since the nature of the applied force, together with the accessories used, does not allow the separation of multiple layers. Furthermore, the variation in the size and shape of the tablets makes the test unfeasible, limiting the analysis to a single presentation of this pharmaceutical form. Therefore, there are no available technical solutions that can satisfactorily solve this problem.

[014] The 3D-printed attachment represents a significant innovation in the field of evaluating the adhesion properties of multilayer tablets. Using this customized holder, it becomes possible to perform tensile tests on universal testing machines accurately and efficiently, allowing for the direct evaluation of adhesion between the different layers of pharmaceutical tablets. This innovative approach overcomes the limitations of conventional attachments, which do not offer a suitable solution for tensile testing, thus enabling the acquisition of crucial data on the axial adhesion strength in these pharmaceutical products.

[015] AMERICAN SOCIETY FOR TESTING AND MATERIALS. Standard Test Method for Peel Adhesion of Pressure-Sensitive Tape D3330 / D3330M - 04, 2018.

[016] AMERICAN SOCIETY FOR TESTING AND MATERIALS. Standard Test Methods for Rating Adhesion by Tape Test D3359 - 23, 2023.

[017] AMERICAN SOCIETY FOR TESTING AND MATERIALS. Standard Test Method for Pull-Off Strength for FRP Laminate Systems Bonded to Concrete or Masonry Substrates D7522 / D7522M - 21, 2021. Petição 870250012561, de 15 / 02 / 2025, pág. 15 / 80 / 10

[018] AKSELI, I. et al. Mechanistic characterization of bilayer tablet formulations. Powder Technology, v. 236, p. 30-36, 2013.

[019] BELLINI, M.; WALTHER, M.; BODMEIER, R. Evaluation of manufacturing process parameters causing multilayer tablets delamination. International Journal of Pharmaceutics, v. 570, n. 118607, p. 118607, 2019.

[020] BUSIGNIES, V. et al. Development of a new test for the easy characterization of the adhesion at the interface of bilayer tablets: proof-of-concept study by experimental design. International Journal of Pharmaceutics, v. 477, n. 1-2, p. 4 7 6 — 484, 2014. SUMÁRIO DA INVENÇÃO

[021] The present technology is not limited to the embodiments described below.

[022] In general, the invention consists of an accessory for a universal tensile testing machine, comprising two main parts, constructed of metallic or polymeric materials, with an adhesive surface suitable for serving as a support for pharmaceutical tablets, which are fixed to the upper and lower parts of a universal mechanical testing machine.

[023] In general, the accessory can be constructed from metallic materials, including metal alloys and polymers, or combinations of polymers, including mixtures of monomers.

[024] Preferably, the polymeric materials used in printing the accessory comprise polylactic acid (PLA), polyvinyl alcohol (PVAL), acrylonitrile butadiene styrene (ABS), polyetheretherketone (PEEK) and high-impact polystyrene (HIPS), and combinations of these polymers. Petition 870250012561, dated 02 / 15 / 2025, page 16 / 80 / 10

[025] Ideally, one of the possible embodiments of the accessory involves obtaining it using 3D printing, constructed from polymeric materials.

[026] Finally, and also in general terms, the use of the invention consists of providing a support for pharmaceutical tablets composed of multiple layers, to enable tensile measurements performed on a universal testing machine. BRIEF DESCRIPTION OF THE DRAWINGS

[027] The invention can be better understood based on the Figures 1 through 8, whose description follows below. Figure 1 shows a three-dimensional perspective drawing of the invention with the two 3D printed accessories and the multilayer tablet fixed between them. Figure 2 presents a three-dimensional drawing of the front view of the invention. Figure 3 shows a three-dimensional drawing of the rear view of the invention. Figure 4 presents a three-dimensional drawing of the left side view of the invention. Figure 5 presents a three-dimensional drawing of the right side view of the invention. Figure 6 presents a three-dimensional drawing of the top view of the invention. Figure 7 presents a three-dimensional drawing of the bottom view of the invention. Petition 870250012561, dated 02 / 15 / 2025, page 17 / 80 / 10 Figure 8 shows the use of the invention in a universal testing machine. On the right, the tablet is shown fixed in the printed accessory, precisely positioned in the grip of the equipment. On the left, the separation of the layers of a tablet after the tensile test is shown. Figure 9 shows the subdivisions of the 3D printed accessory. Figure 10 shows the dimensions of the 3D printed accessory. Description of the invention

[028] In this way, the objective of the present invention is to provide an innovative and effective technical solution for evaluating the adhesion properties of multilayer tablets, solving a technical difficulty and allowing a precise and reliable analysis of the interfacial adhesion strength between the layers through a tensile test. Through the development of this accessory, it will be possible to enable the improvement of quality control protocols for these medications, contributing to the quality and performance of treatments available on the market.

[029] The difficulty in obtaining data on the mechanical properties of adhesion between tablet layers directly compromises the quality and performance of medications, negatively impacting the effectiveness of treatments. The introduction of this new accessory allows for the fixation of multilayer tablets of varying sizes, shapes, and number of layers, given that 3D printing enables the customization of the part for any test specimen, allowing for its axial traction by the grip of the universal testing machine. Furthermore, obtaining these accessories through the fused deposition modeling technique allows for the printing of customized supports for any universal testing machine. Petition 870250012561, dated 02 / 15 / 2025, page 18 / 80 / 10

[030] Additionally, the invention makes it possible to implement methodologies for evaluating the performance of multilayer tablets with regard to interfacial adhesion properties. In this context, in addition to enabling more adequate quality control, the invention contributes to the characterization of these pharmaceutical products in their research and development process, allowing the evaluation of the influence of various variables such as the use of lubricants, disintegrants, binders, as well as verifying the influence of compression parameters and matrix heterogeneity on the adhesive properties between the layers.

[031] The preferred embodiment of the present invention begins with the design of the part to be printed, a step that can be performed in any software that allows the creation of three-dimensional objects, such as CAD. It is important to highlight that the part must be designed to fit perfectly into the equipment to be used and be able to hold the multilayer tablet to be analyzed. Next, the printing of the adapter accessory is carried out on an FDM 3D printer. The polymeric materials used in printing include, but are not limited to, polylactic acid (PLA), polyvinyl alcohol (PVAL), acrylonitrile butadiene styrene (ABS), polyetheretherketone (PEEK), and high-impact polystyrene (HIPS), and combinations of these polymers.

[032] With the aid of a cyanoacrylate-based adhesive, the test specimen is fixed to the 3D attachment, which in turn is positioned in the grip of the universal testing machine. For each analysis, two attachments are used, each fixed to one of the faces of the tablets. Thus, during the test, the tablet is positioned in the center and the attachments are fitted into their respective grips, located at the top and bottom of the equipment. In this way, the tensile test is initiated, and the equipment applies an axial force at a pre-set speed. Petition 870250012561, dated 02 / 15 / 2025, page 19 / 80 / 10 determined, with the objective of separating the layers of the tablet and determining the interfacial tension between them.

[033] It is crucial to emphasize that the use of polymeric material to construct the accessory on the 3D printer, as well as cyanoacrylate-based glue to fix the test specimen, guarantees the resistance of the materials, whose adhesion is superior to that of the tablet layers, eliminating any interference in the result of the experiment. In this way, the use of the accessory developed by 3D printing allows for the proper fixation of the test specimen and the performance of tensile tests to evaluate interfacial adhesion in multilayer tablets, something that cannot be done otherwise.

[034] Thus, the developed accessory consists of two main parts, designed to precisely fit the upper and lower faces of the tablet during the tensile test. The support surfaces ensure a firm and stable fixation of the test specimen, aided by the glue, preventing any slippage during the test. The dimensions of the support can be customized to accommodate different tablet sizes and shapes, and also vary according to the type of grip and equipment used. In this specific case, the support has a circular base with a diameter of 13 mm and a height of 4 mm for fixing the tablets, while the upper part, which fits into the equipment, measures 8 x 8 mm, with the portion outside the grip measuring 9 x 12 mm to provide support. The connection between the circular base and the upper part is made by a pyramidal structure, which has a height of 6 mm and a base of 5 x 5 mm.These specifications for each region and the accessory measurements are described in Figures 9 and 10. Petition 870250012561, dated 02 / 15 / 2025, page 20 / 80

Claims

CLAIMS 1. ACCESSORY FOR UNIVERSAL TRACTION MACHINE characterized by comprising two main parts, constructed of metallic or polymeric materials, with their own adhesive surface, which are fixed to the upper and lower parts of a universal mechanical testing machine.

2. ACCESSORY FOR UNIVERSAL TRACTION MACHINE, according to claim 1, characterized in that the metallic materials comprise metals and metallic alloys, polymeric materials and combinations of polymers.

3. ACCESSORY FOR UNIVERSAL TRACTION MACHINE, according to either of claims 1 and 2, characterized in that the polymeric materials comprise combinations of polymers, including mixtures of monomers.

4. ACCESSORY FOR UNIVERSAL TRACTION MACHINE, according to any one of claims 1 to 3, characterized in that the polymeric materials comprise polylactic acid (PLA), polyvinyl alcohol (PVAL), acrylonitrile butadiene styrene (ABS), polyetheretherketone (PEEK) and high-impact polystyrene (HIPS), and combinations of these polymers.

5. ACCESSORY FOR UNIVERSAL TRACTION MACHINE, according to any one of claims 1 to 4, characterized by being constructed using 3D printing technology, from polymeric materials.

6. USE OF AN ACCESSORY FOR A UNIVERSAL TRACTION MACHINE characterized by being for supporting pharmaceutical tablets, composed of multiple layers. Petition 870250012561, dated 02 / 15 / 2025, page 21 / 80

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