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Compressed Solids Formulations
Published in Sarfaraz K. Niazi, Handbook of Pharmaceutical Manufacturing Formulations, Third Edition, 2019
Tablets: each tablet contains 500 or 875 mg of amoxicillin as the trihydrate. Each film-coated, capsule-shaped, pink tablet is embossed with AMOXIL, centered over 500 or 875, respectively. The 875 mg tablet is scored on the reverse side. The inactive ingredients are colloidal silicon dioxide, crospovidone, FD&C Red No. 30 Aluminum Lake, hydroxypropyl methylcellulose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, sodium starch glycolate, and titanium dioxide.
Validation of Solid Dosage Finished Goods
Published in James Agalloco, Phil DeSantis, Anthony Grilli, Anthony Pavell, Handbook of Validation in Pharmaceutical Processes, 2021
Sustained release dosage or modified release (also called extended release and other marketing names) typically has wide acceptance criteria for active ingredients at the end of the release period. This range is necessary to accommodate the inherent variability in raw materials and processing in this class of formulations. As stated earlier, especially in this case, limits should not be “tightened for validation.” The dosage is intended to aid in patient compliance and/or for marketing. The dosage form typically consists of film-coated tablets. There is a usually a solid matrix in which the drug diffuses out. There are many different materials, usually polymers, to achieve the desired dissolution profile. There may be more than one dissolution test to include in validation testing, and separate core and coated tablet testing complicates batch subdivision into segments for valuation testing. In one type where hard gelatin capsules are used, nonpareils beads (sucrose spheres) are coated with solutions containing the active ingredient with different release rates. The beads are tested, and then different proportions are blended and then encapsulated to make the final dosage. In another case, the active ingredient is formed into granules in a fluid bed granulator, which are then coated with an inactive coating solution. The granulator consists of a vertical air-stream that suspends the solid particles. A granulating solution is sprayed into the stream to agglomerate the suspended particles to a desired size. Critical process parameters are air temperature, relative humidity, velocity, solution properties of temperature, viscosity and density. In another type of sustained release, a coated tablet is drilled with a laser beam to provide a zero order release (constant release rate with time). This proprietary process was marketed, so it may be encountered in multiple firms. Hole geometry is critical, and the tablets are cut in half and viewed microscopically and measured. The profile visually resembles a “golf tee,” which makes a good in-process test for the drilling operation. Otherwise, the CPPS associated with the coating operation must be considered (see “Coating,” Section 42.6.2). Formulations with two or more ingredients can be problematic with differing release rates. In one instance the author recalls that, in a tablet purporting to be effective for 24 hours, one component was problematic after eight hours. This firm went into Consent Decree for this and other problems. In another instance (Hydrochlorothiazide and Triamterene capsules), the dissolution profile could not be duplicated by generic manufacturers after the innovator’s product came off patent.
Photoinduced movement: how photoirradiation induced the movements of matter
Published in Science and Technology of Advanced Materials, 2022
Tetsuo Yamaguchi, Makoto Ogawa
In order to clarify the effect of the surface tension on the SRG formation, SRG of a photoinactive polymer (PCPBz, the structure is given in Figure 17, (b)) film coated with AZ polymer (PAz, the structure is given in Figure 17, (b)) was studied [314]. Although the PCPBz film (the thickness of 200 nm) without the PAz coating did not give SRG by UV irradiation with a photomask as shown in Figure 17, (Ca), the PCPBz films with the PAz coating prepared by Langmuir-Schaefer (LS) method gave the SRG. Moreover, the formation of SRG of the PAz films was disturbed by poly(octadecyl methacrylate) (PC18, the structure is given in Figure 17, (b)) coating, suggesting that change of the surface tension was suppressed by the photoinactive PC18 coating (Figure 17, (d)). It was concluded that Marangoni flow was major driving force for the SRG formation in AZ polymers and further studies to establish a unified model which explains all SRG systems are expected. Based on the conclusion, studies on SRG of photoinactive polymers ionically interacted with AZ molecules were reported to show beneficial aspects of photoinduced surface tension difference with keeping high mobility of the components [237,278,315,324].
Determination of the relative humidity at the parts-per-million (ppm) level in gases by a nanoporous alumina thin-film on a surface acoustic wave (SAW) resonator
Published in Instrumentation Science & Technology, 2022
Shamim Alam, Shakeb A. Khan, Upendra Mittal, Tarikul Islam
The lower limit of the sensor is 6 ppm which is the moisture concentration of dry nitrogen gas. We are unable to obtain a response at lower moisture concentrations due to unavailability of dry nitrogen gas with moisture concentration below 6 ppm. The sensor can work at percentage relative humidity levels but we restricted experiments to ppm moisture detection only. There are some works by the authors to measure relative humidity using oxide film/polymer film coated SAW sensors.[13,16] When the water molecules are adsorbed in the Al2O3 film, the effective mass loading increases, so the resonant frequency decreases. However, when the water molecules desorb, the frequency increases due to a decrease in mass loading. Because of the thin sensing layer, the response is fast and the hysteresis error is negligible. The response is governed by the pore morphologies that are determined by the average dimension of the pore, the distribution of the pores, and the thickness of the porous layer. A comparison of the response parameters of the sensor with the commercial meters and other reported works for humidity measurement in ppm level is shown in Table 1.
Fabrication and characterization of polysulfone reinforced hollow fibre membrane
Published in Environmental Technology, 2021
Turker Turken, Reyhan Sengur-Tasdemir, Gulsum Melike Urper-Bayram, Oguz Gunes, Esra Ates-Genceli, Volodymyr V. Tarabara, Ismail Koyuncu
Hollow fibre membranes are mechanically self-supporting and easy to assemble in modules which are attractive for industrial use [9]. However, hollow fibre membranes are liable to be damaged or broken by the high-pressure cleaning process. Therefore, it is important to improve the mechanical stabilities of hollow fibre membranes for high pressure requiring membrane processes. High mechanical strength that allows to use of hollow fibre membranes in nanofiltration or reverse osmosis process can be provided by braided reinforced hollow fibre membranes [10,11]. The first reinforced hollow fibre concept is introduced by Hayano et al (1976). They proposed a method for reinforced hollow fibre membranes [12]. However, the method was found impractical for fabricating capillary membranes. Today's technology uses the concept introduced by Lee et al. Lee et al. (2008) has invented a braid-reinforced hollow fibre membrane that contains a reinforcement tubular braid and a polymer resinous thin film coated on the surface of the reinforcement tubular braid. Instead of tubular braid, a fabric or threads can also be used for reinforcing and supporting the hollow fibre membrane owing to their excellent mechanical strength [13].