Microbial Monitoring of a Manufacturing Facility
Philip A. Geis in Cosmetic Microbiology, 2020
Centrifugal air samplers use a propeller or turbine housed in an open drum to sample a known volume of air. The collected air is then accelerated by centrifugal force toward the inner wall of the drum lined with a flexible plastic strip containing a microbial growth agar that is impacted by sampled airborne particle (1,6). Centrifugal air samplers have been reported to selectively recover larger particles resulting in higher airborne counts than other types of air samplers (5). The advantages of centrifugal air samplers are as follows: convenience of operation, portability, a self-contained electrical power supply, autoclavable head assembly, large volumes of air can be sampled, and airflow can be calibrated. Disadvantages include use of specialized microbial growth agar strips requiring additional handling, direct calibration of sampling volume is not possible, and the use of the unit will cause a disruption of the airflow in a laminar flow hood.
Bone Marrow Processing with the Haemonetics V50 Plus™
Adrian P. Gee in BONE MARROW PROCESSING and PURGING, 2020
Increase the centrifuge speed to 5600 rpm in 200 rpm increments by completing the following sequence: Press MODAC/BLOOD RATIO 08Press MODRBC VOLUME 999Press MODCENTRIFUGE SPEED 3000Press 3200Press ENTER The centrifuge increases in speed to 3200 rpm. Repeat this sequence increasing the centrifuge speed by 200 rpm each time until 5600 rpm is reached. After each increase wait until the rbc layer has settled before incrementing the speed again (approximately 5 s).
Tissue is the Issue
Brian Leyland-Jones in Pharmacogenetics of Breast Cancer, 2020
Magnetic labeling (~45 min) Centrifuge sample for 10 minutes at 300g at room temperature.Carefully remove the supernatant completely.Resuspend cell pellet in appropriate amount of buffer as specified by the microbeads package insert. For fewer cells, use the same volume.Add microbeads per package insert.Incubate for 15 minutes at 6°C to 12°C. For less than 5 x 106 total cells, use the same volume.Wash cells by adding 10 to 20 times the labeling volume of buffer and centrifuge at 300g for 10 minutes.Remove supernatant completely (save the supernatant in appropriately labeled 1 mL cryovial) and resuspend cell pellet in appropriate amount of buffer (1 mL of buffer/108 total cells).Proceed to magnetic separation.
Increased brain uptake of pterostilbene loaded folate modified micellar delivery system
Published in Drug Delivery, 2022
Yinan Wang, Yanan Su, Yunqiao Yang, Huan Jin, Moli Wu, Qian Wang, Pengyuan Sun, Jianbin Zhang, Xiaobo Yang, Xiaohong Shu
Folate modified pterostilbene loaded PEG2000/PEG3400-PCL2000 micelles (F-Pt/M) were formulated using a thin-film hydration method (Zheng et al., 2015; Mei et al., 2019). In brief (see Figure 1), Pt, PEG2000-PCL2000 and Folate-PEG3400-PCL2000 of various concentrations and proportions were dissolved in acetone in a round-bottom flask. The organic solvent was removed at 45 °C by vacuum rotary evaporation to form a dry film at the bottom of the flask. The obtained film was further dried overnight under vacuum to remove any traces of remaining acetone. After adding the preheated PBS (55 °C) to hydrate the film, the system was vortexed and sonicated for 10 min, respectively. Free unentrapped Pt was removed via using centrifugation method. Separation was carried out by centrifuging at 10,000 rpm for 10 min (Centrifuge H1650-W, Xiangyi, Hunan). Finally, the supernatant was extruded through a polycarbonate membrane of 220 nm pore size for 10 times using a laboratory extrusion device (LiposoFast Basic LF-1, Avestin Inc., Ottawa, Canada). In addition, blank micelles (BM) and pterostilbene loaded micelles (Pt/M) were prepared via the same way. To study the uptake of folate modified micelles by cancer cells, the coumarin-6 (C6), a fluorescent material, loaded micelles (C6/M and F-C6/M) were prepared as well.
Olive oil and clove oil-based nanoemulsion for topical delivery of terbinafine hydrochloride: in vitro and ex vivo evaluation
Published in Drug Delivery, 2022
Uzma Gul, Muhammad Imran Khan, Asadullah Madni, Muhammad Farhan Sohail, Mubashar Rehman, Akhtar Rasul, Leena Peltonen
Dispersion stability studies for both the optimized formulations (F1 and F7) were carried out in order to confirm the good stability of the systems. For this purpose, developed formulations were subjected to stressed conditions: heating cooling, centrifugation and freeze-thaw tests (Shafiq et al., 2007). In heating cooling stress, six cycles between refrigerator temperature (4 °C) and 45 °C with storage at each temperature at least 48 h were studied. In centrifugation, formulations were centrifuged at 3500 rpm for 30 min. And, in freeze-thaw stressing, three freeze-thaw cycles between −21 °C and +25 °C with storage at each temperature not less than 48 h was done. After the stressing, formulations were checked for creaming, phase separation, and cracking.
Quantification methods for viruses and virus-like particles applied in biopharmaceutical production processes
Published in Expert Review of Vaccines, 2022
Keven Lothert, Friederike Eilts, Michael W. Wolff
The differential centrifugal sedimentation is mainly used for the determination of the size distribution of particles in solutions, based on their settling velocity. For this purpose, particles are injected into a rotation disc, filled with a density gradient of a fluid, through which the particles settle until they are detected at the endpoint of the disc radius by light attenuation. In the area of vaccine production, differential centrifugal sedimentation is generally used for the size characterization of vaccine formulations and for the monitoring of virus aggregations [131–133]. However, the peak area of the particle sedimentation curve can be used to determine the amount of particles, although this is not trivial [147]. To obtain particle concentrations, the measured size-distribution must be converted into a mass-weighted size distribution, which can then be used for the quantity calculation, based on the integrated peak and the knowledge about individual particle weights. A limitation is the difficult discrimination between virus- and other particles, such as extracellular vesicles.
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