Advances in Primary and Revision Hip Arthroplasty
K. Mohan Iyer in Hip Joint in Adults: Advances and Developments, 2018
The polyethylene acetabular component forms part of the traditional bearing couple, that is, hard on soft, which articulates with a metal or ceramic head. A major factor influencing prosthetic survival is wear of the polyethylene with its debris, causing osteolysis and loosening of hip components. Advances in reducing the wear characteristics of polyethylene focused on three stages: manufacturing, sterilisation and shelf life. The types of polyethylene include high-density polyethylene (HDP), ultra-high-molecular-weight polyethylene (UHMWPE), highly cross-linked polyethylene (HCLPE) and vitamin E-doped polyethylene (E-Poly). The direct compression moulding technique has been identified as the preferred manufacturing process to achieve consistently lower wear rates. Inferior wear characteristics are achieved with other manufacturing techniques, such as ram bar extrusion with secondary machining, hot isostatic pressing into bars with secondary machining and compression moulding into bars with secondary machining. The calcium stearate component of the lubricant used to protect the processing equipment was recognised to produce unfused polyethylene particles, thus diminishing the mechanical properties of the final product. It was therefore avoided in the manufacturing process.
Roller Compaction Technology
Dilip M. Parikh in Handbook of Pharmaceutical Granulation Technology, 2021
The API physical property characteristics, cohesive/adhesive, particle size and distribution, low density—typically less than 0.4 g/cc—and morphology are the keys to determine if the API powder property behavior is a good or bad actor. Generally, if the API powder has poor powder properties, then more or very specific excipients are needed to enhance powder flow to assist roller compaction processing. Typical pharmaceutical excipient selections for roller compaction formulations are cited here. Specific ingredients and concentrations vary depending on the aforementioned drug product release discussion. Useful formulation starting points are noted here.Filler/diluents/binders—microcrystalline cellulose, mannitol, corn starch, povidone, tribasic calcium phosphate, lactose, HPC, HPMC ~10% to 90%.Disintegrants—sodium starch glycolate, (all; half intra and half extra), ~ 1% to 1.5%.Lubricants—magnesium stearate, PEGs, SSF, stearic acid, calcium stearate ~1%.Glidants—colloidal silicon dioxide ~ 0.5%.Surfactant—sodium lauryl sulfate ~ less than 0.5%.
Predicting Stability in Rheologically Modified Systems
Laba Dennis in Rheological Proper ties of Cosmetics and Toiletries, 2017
In practice, differences in cohesive energy at single lamellar interfaces, measured as interfacial tension, are usually too large, or surfactant quantity is too small, to form stable microemulsions. As a result, gravitational separation, coalescence, flocculation, and disproportionation (36) are the normal mechanisms producing instability. These processes must be retarded or overcome to introduce relative stability. Rheological additives serve well to increase viscous flow in the external phase of emulsions, blocking coalescence and creaming. Hydrocolloids, inorganic clays and fillers, are among common systems described in other chapters to modify the outer phase of oil-in-water (O/W) systems. Water-in-oil (W/O) systems may also be stabilized by oil-miscible polymers, or organic-inorganic complexes such as calcium stearate, or the calcium saccharates studied by Thau (37). In any case, structure is introduced into the outer phase.
Analytical approach for lubricant characterization of excipients using the surface replication method
Published in Drug Development and Industrial Pharmacy, 2021
Shinichi Saito, Takashi Osamura, Tadatsugu Tanino, Satomi Onoue
Raloxifene hydrochloride (RH) was purchased from Erregierre S.P.A. (San Paolo d'Argon, Italy). Granulated lactose (Dilactose S, Freund Co. Ltd., Tokyo, Japan), polyvinylpyrrolidone K30 (PVP: K-30, Dai-ichi Kogyo Seiyaku, Tokyo, Japan), and various lubricants were purchased from the indicated sources. Formulation I contained no lubricant. Formulations II, III, and IV contained stearic acid (NOF Corporation, Tokyo, Japan), sodium stearyl fumarate (SSF, JRS PHARMA GmbH & Co. KG, Rosenberg, Germany), and calcium stearate (Ca-St, NOF Corporation, Tokyo, Japan), respectively (Table 1). Three different grades of magnesium stearate (Mg-St, Taihei Chemical, Ryoke Kawagachi, Japan) were purchased (Supplementary Table 1). Formulations V, VI, and VII contained magnesium stearate, magnesium stearate (special), and magnesium stearate (light), respectively (Table 1).
Microstructural and heavy metal analysis of gallstones prevalent in Jharkhand and its implications in the treatment
Published in Postgraduate Medicine, 2023
Bhavna Sharma, Shubha Rani Sharma
XRD patterns that were obtained for different gallstones are shown in Figure 10. We used three samples of each type of gallstones for the analysis. XRD analysis of pure cholesterol gallstones gave d-spacing values corresponding to cholesterol (5.46, 4.60,4.31,4.12,3.43, and 3.79 Å) and calcium phosphate (3.40, 2.75, 2.55,2.24, 2.02 and 1.97 Å) standard which confirmed their presence in it. Further, the diffraction pattern of mixed stones showed the presence of cholesterol (3.91 and 4.75 Å), calcium bilirubinate (3.39 Å), calcium phosphate (3.29, 2.74, 2.71, 2.67, 2.60, 1.89 and 1.41 Å), calcium carbonate(3.39, 2.37 and 1.41 Å), calcium palmitate and stearate (3.54 and 2.17 Å) in them. Next, the XRD patterns of pigmented stones showed the presence of calcium bilirubinate (2.78 Å), calcium phosphate (2.24, 1.78, 1.63, 1.53 and 1.46 Å) and calcium carbonate (1.53 and 1.46 Å) in them. No peaks were observed for cholesterol in them. Also, the sharp peaks obtained depicted a crystalline structure. Weerakon et al. also reported the presence of cholesterol, calcium carbonate calcium phosphate in mixed gallstones but the presence of calcium stearate and palmitate was not detected [9].
Preparation and characterization of metformin hydrochloride controlled-release tablet using fatty acid coated granules
Published in Drug Development and Industrial Pharmacy, 2020
Ji-Hyun Kang, Myung-Hee Chun, Mi-Seo Cho, Yong-Bin Kwon, Jae-Cheol Choi, Dong-Wook Kim, Chun-Woong Park, Eun-Seok Park
Metformin hydrochloride was a gift from Han-dok pharmaceuticals Co. Ltd. (Seoul, South Korea). Magnesium stearate (MGS) was acquired from Duksan chemical Co. Ltd. (Seoul, South Korea). Aluminum stearate (ALS) was obtained from Sigma-aldrich Co. Ltd. (St. Louis, MO, USA). Calcium stearate (CAS) and polyethylene oxide (WSR coagulant M.W. 5 M PEO) were purchased from Samchun Chemical Co. (Pyeongtaek, South Korea). Stearic acid (SA) was provided by Tokyo Chemical Industry Co. Ltd. (Tokyo, Japan). Xanthan gum was the product of Daejung Chemical Co. Ltd. (Siheung, South Korea). The high performance liquid chromatography (HPLC) grade solvents were used for the analysis process.
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