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GMP
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Production of more than one radioactive product in the same hot cell or laminar flow unit should be avoided to minimize cross-contamination. A dedicated area and equipment should be provided if a radiopharmaceutical contains human blood or plasma. The membrane filter used for sterile filtration for aseptically filled radiopharmaceuticals should be tested for integrity prior to release, taking into account radiation protection. The labelling of the primary vial or direct container can be done prior to manufacture and, in any circumstances sterility and visual control of the filled vial should not be compromised.
Antimicrobial Preservative Efficacy and Microbial Content Testing*
Published in Philip A. Geis, Cosmetic Microbiology, 2020
Scott V.W. Sutton, Philip A. Geis
Another test for the neutralization of a biocide on a membrane filter involves placing a known number of microorganisms on the membrane without the biocide and placing the same number of microorganisms again on another membrane that has been exposed to a disinfectant. The disinfectant is rinsed through (and thus off) the membrane filter by placing neutralizing agent onto the filter and allowing the neutralizer to go through the filter using vacuum or pressure. If the two membranes show equal counts, then the disinfectant has been neutralized. If the disinfectant is bound to the membrane, then counts will be significantly lower than the counts on the membrane not exposed to the biocide (22).
Selection Considerations for Membranes and Models for In Vitro/Ex Vivo Permeation Studies
Published in Tapash K. Ghosh, Dermal Drug Delivery, 2020
Pei-Chin Tsai, Tannaz Ramezanli, Dina W. Ameen, Sonia Trehan, Nathaly Martos, Zheng Zhang, Bozena Michniak-Kohn
The phospholipid vesicle-based permeation (PVPA) model was essentially designed to mimic the human stratum corneum. This model is based on tightly fused liposomes on a polymeric membrane filter support (cellulose ester; 0.65μm pore size) in Transwell plates and is used to predict passive diffusion of drugs through a skin barrier. Engesland et al.85 tested the permeation of model drugs, indomethacin, salicylic acid, ibuprofen, flufenamic acid, calcein and FITC-dextran across different PVPA models. They demonstrated, by modifying the lipid composition of the liposomes in the PVPA model to 50% egg phophatidylcholine/27.5% ceramides/12.5% cholesterol/2.5% cholesteryl sulfate/7.5% palmitic acid, a better mimic of the stratum corneum barrier was achieved. Moreover, they suggested that the liposomes could be viewed as simple models of cells that may mimic in vivo structures to a greater extent compared with the continuous lipophilic environment that is present in the PAMPA models. In addition, the prediction of partitioning between liposomes and the buffer may lead to better predictions of permeation as compared to those obtained from octanol and water experiments. However, a direct comparison of the permeation profile to human skin is still needed to establish the real correlations between the PVPA model and human skin.
Improved pharmaceutical properties of ritonavir through co-crystallization approach with liquid-assisted grinding method
Published in Drug Development and Industrial Pharmacy, 2021
Khushbu R. Chaudhari, Jignasa K. Savjani, Ketan T. Savjani, Harsh Shah
Solubility studies of pure drug and cocrystal samples were performed in distilled water. All the samples in excess quantity (100 mg) were added in 5 ml of double-distilled water (HPLC grade), and the prepared suspensions kept in an orbital shaker for 24 h. Single-wavelength UV spectra of Ritonavir and coformer L-tyrosine was performed to check any possible interference of L-tyrosine spectra in quantification of Ritonavir in sample. Ritonavir single-wavelength scan showed peak at UV λmax 240 nm and L-tyrosine scan showed peak at UV λmax 277 nm and showed no absorption at 240 nm that avoided the possible interference of L-tyrosine in the measurement of Ritonavir in cocrystal sample quantification. In addition, the blank was run with coformer to consider the solubility of L-tyrosine while calculating solubility of cocrystals. Therefore, all the UV quantifications of Ritonavir were performed using Shimadzu UV-1800 Japan Spec UV spectrophotometer at a λmax 240 nm. All the solutions were filtered through a 0.45-µm membrane filter and analyzed. The study was conducted in triplicate (n = 3).
Oral delivery of indinavir using mPEG-PCL nanoparticles: preparation, optimization, cellular uptake, transport and pharmacokinetic evaluation
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Masoumeh Kurd, Soroor Sadegh Malvajerd, Saeed Rezaee, Mehrdad Hamidi, Katayoun Derakhshandeh
The effect of Papp coefficient of free IDV and encapsulated IDV on Caco-2 cell monolayer was studied with different concentrations Figure 4(C). Formation of the cell monolayer has been ensured using an optical microscope. The confluent cell monolayer has been formed on the transwell membrane filter after 21 days. The results of transport studies illustrated that IDV solution causes a significant decrease in transports of IDV across the cell monolayer compared to encapsulated IDV (p < 0.05). The amount of transported IDV that passed through the Caco-2 cells increased by increasing the concentration. The values of Papp coefficient, less than 1 × 10−6 cm/s, show low permeability more than 2 × 10−6 cm/s show intermediate permeability and values above 10 × 10−6 cm/s show high permeability [47,48]. Using these criteria, it is clear from Figure 4(C) that the majority of the compounds which have been studied in IDV-mPEG-PCL NPs and Caco-2 monolayers are highly permeable. Increasing the efficiency of transport of IDV-mPEG-PCL NPs is regulated by considering the polymer hydrophobicity. PCL can interact better with intestinal epithelium due to the hydrophobic-hydrophilic interaction.
Liposome: composition, characterisation, preparation, and recent innovation in clinical applications
Published in Journal of Drug Targeting, 2019
Kamel S. Ahmed, Saied A. Hussein, Abdelmoneim H. Ali, Sameh A. Korma, Qiu Lipeng, Chen Jinghua
Liposome extrusion occurs- by pushing the large MLVs solution through filters of polycarbonate membrane. The desired vesicles size controlled by the applied pressure, since the average size decreases upon increasing the extrusion pressure [53], also decreasing the pore size of the filter membrane result in reduction in size and size distribution of the liposomes, it was reported that using filter membrane with pore size larger than 0.2 µm the size of the obtained liposomes was smaller than the membrane pore size, but by using a membrane with a pore size smaller than 0.2 µm, the size of the produced liposomes was slightly larger than the filter pore size [54]. And also, another study proved that filtering of the MLVs solution using a filter membrane with pore size ∼1 µm followed by five times repeated filtration through 0.4- and 0.2-µm pores. Then five to ten extrusions using a 100-nm membrane pore size will result in the formation of large unilamellar vesicles with size ∼110–120 nm. If the size is needed to be smaller, continuous filtration using a membrane filter with 80- and 50-nm pores size is required. The vesicles treated by the extrusion techniques characterised by proper homogeneity and easy to control the vesicles size distribution, especially for vesicles of large diameters (100–500 nm) [51].