The effects of locations on the build tray on the quality of specimens in powder bed additive manufacturing

In this study, the effect of powder spreading direction was investigated on selectively laser-melted specimens. The results showed that the metallurgical properties of the specimens varied during fabrication with respect to their position on the build tray. The density, porosity, and tensile properties of the Co–Cr–W–Mo alloy were investigated on cuboid and tensile specimens fabricated at different locations. Two different significant positions on the tray were selected along the powder spreading direction. One set of specimens was located near the start line of powder spreading, and the other set was located near the end of the building tray. The main role in the consequences of powder layering was played by the distribution of powder particle sizes and the packing density of the layers. As a result, laser penetration, melt pool formation, and fusion characteristics varied. To confirm the occurrence of variations in sample density, an additional experiment was performed with a Ti–6Al–4V alloy. Furthermore, the powders were collected at two different fabricating locations and their size distribution for both materials was investigated.

FORMULATION AND EVALUATION OF SUSTAIN RELEASE CYCLOBENZAPRINE HYDROCHLORIDE PELLETS

Cyclobenzaprine Hydrochloride is a centrally acting muscle relaxant which is mostly available in the form of tablets and capsules. The present aim of the study was to develop a sustained release formulation of cyclobenzaprine Hydrochloride pellets using powder layering technique. Nine different formulations of pellets were prepared by using different concentrations of Ethyl Cellulose-50, Hypromellose (HPMC), and PEG 6000 of all formulations, F8 formulation was the optimized formulation. The kinetic studies of F8 formulation was best fitted in the First order model as it had the highest value (R2 = 0.981) and it follows non- fickian diffusion. Among all the formulations F8 gave better drug release 85.7% when compared to innovator, F8 was selected as optimized formulation. The optimized formulation was kept for stability studies for 3 months at 40°C /75% RH and 25°C /60% RH and the results indicated that there was no much variation in their physiochemical characteristics and the formulation was found to be stable.

СУЧАСНИЙ СТАН СТВОРЕННЯ, ВИРОБНИЦТВА ТА ДОСЛІДЖЕННЯ ТАБЛЕТОВАНИХ ЛІКАРСЬКИХ ПРЕПАРАТІВ Повідомлення 19. Сучасний стан розробки та дослідження мультипартикулярних пелетних систем.

<p align="center"><strong>MODERN STATE OF CREATION, PRODUCTION AND RESEARCH OF DRUGS</strong></p><p align="center"><strong>M</strong><strong>.</strong><strong>B</strong><strong>. </strong><strong>Demchuk</strong><strong>, </strong><strong>S</strong><strong>.</strong><strong>M</strong><strong>. </strong><strong>Gureyeva</strong><strong>¹</strong><strong>, </strong><strong>T</strong><strong>.</strong><strong>A</strong><strong>. </strong><strong>Hroshovyi</strong><strong></strong></p><p>TernopilStateMedicalUniversityby I.Ya. Horbachevsky</p><p>¹JSC “Farmak”</p><p><strong>Noti</strong><strong>ce</strong><strong> 19.</strong> The current state of development and research of multiple unit pellet systems.</p><p><strong>Summary: </strong>the literature on technological aspects of creations of pellets, features of compression pellet to obtain multiple unit pellet systems are summarized<strong>.</strong></p><p><strong>Keywords: </strong>pellets, methods of pellets, pellet pressing, multiple unit pellet systems.</p><p><strong>Introduction. </strong>Oral modified-release multiple-unit dosage forms have always been more effective therapeutic alternative to conventional or immediate release single-unit dosage forms. With regards to the final dosage form, the multiparticulates are usually formulated into single-unit dosage forms such as filling them into hard gelatin capsules or compressing them into tablets.</p><p>Pelletization is a technique that enables the formation of spherical beads or pellets with a mean diameter usually ranging from 0.5 to2.0 mm. These pellets can evantually be coated and very often used in controlled-release dosage forms. The use of pelletization and pellets leads to an improvement in the flowability, appearance and mixing properties, thus avoiding excessive dust and reducing segregation and, generally, eliminating undesirable properties and improving the physical or chemical properties of fine powders.</p><p>The pharmaceutical industry has developed a great interest in pelletization due to a variety of reasons:</p><p>– prevention of segregation of co-agglomerated components, resulting in an improvement of the uniformity of the content;</p><p>– prevention of dust formation;</p><p>– increasing bulk density and decreasing bulk volume;</p><p>– the defined shape and weight improves the appearance of the product;</p><p>– improvement of the handling properties, due to the free-flowing properties;</p><p>– improvement of the hardness and friability of pellets;</p><p>– controlled release application of pellets due to the ideal low surface area-to-volume ratio that provides an ideal shape for the application of film coatings.</p><p>Pellets are prepared by different techniques, such as extrusion and spheronisation, rotogranulation, solution, suspension or powder layering, spray-drying or spray-congealing.</p><p>Extrusion / spheronisation is a multistage process for obtaining pellets with uniform size from wet granulates (extrudates). The process is more labour-intensive and more expensive than the conventional wet-granulation technique, as its use should be limited only to the production of spherical pellets for controlled release of drugs.</p><p>The fluid-bed granulation consists in the spraying of a granulation solution onto the suspended particles, which then are dried rapidly in the hot air stream.</p><p>Rotogranulation is one of the most recent methods for the production of spheroids. The single-unit spheronizing system can be described using terms like centrifugal granulator, rotary fluidized-bed granulator, rotary fluid bed, rotary processor or rotor granulator.</p><p>Layering a suspension or a solution of a drug on a seed material (usually, a coarse crystal or nonpareil) can produce pellets that are uniform in size distribution and generally posess very good surphace morphology. These characteristics are especially desirable when pellets will be coated for the purpose of achieving a controlled release.</p><p>Dry powder layering is similar to the solution or suspension layering. Instead of these dispersions, the layering is performed using a drug powder.</p><p>Spray-drying represents another process with limited application in the development of pharmaceutical pelletized products, based on globulation. During spray-drying, a drug solution or suspension is sprayed, with or without excipients, into a hot-air stream, generating dry and highly spherical particles.</p><p>Spray-congealing (spray-chilling) is a technique similar to spray-drying. Spray-congealing is a process in which a drug is allowed to melt, disperse or dissolve in hot melts of gums, waxes, fatty acids or other melting solids. The dispersion is then sprayed into a stream of air and other gases with a temperature below the melting point of the formulation components.</p><p><strong>Conclusions.</strong> The basic requirements and approaches to development multiple unit pellet system, aspects and examples receipt of pellets and tablets based on them are described.</p>

Microstructure and Properties of WCP/Cu Layered Functionally Graded Materials Prepared by Vacuum Hot-Pressed Sintering

The aim of this study is to fabricate WCp/Cu functionally graded materials (FGMs) and test its properties. Vacuum Hot-pressed Sintering technique is used to develop the graded WC particle reinforced Cu matrix composite. Using powder layering technique, a multi-layered WCp/Cu FGM have been prepared successfully. Scanning electron microscopy is used for microstructural analysis. Microscopic observations display that the microstructure of WCp/Cu FGM distribute gradually, and have no visible macroscopic interface. The mechanical properties of WCp/Cu functionally graded materials have been investigated, including Vickers's hardness, Young’s modulus and Tensile strength. Experimental results show that the properties of WCp/Cu FGM strongly depend on compositional variation.