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Engineering Stable Spray-Dried Biologic Powder for Inhalation
Published in Anthony J. Hickey, Sandro R.P. da Rocha, Pharmaceutical Inhalation Aerosol Technology, 2019
Nicholas Carrigy, Reinhard Vehring
It may be of interest to store the powder at a low, but optimized non-zero moisture content since very dry powder may lead to increased degradation and electrostatic charging can make filling and handling difficult [33,47,188]. The simplest method for equilibrating moisture for passive relative humidity control is to place the materials in an environmental chamber that is set to the desired relative humidity and temperature [316]. The moisture adsorbed to the packaging material and desiccant and in the headspace of the packaging material should be equilibrated to the desired level prior to packaging. The desiccant is most crucial to equilibrate, as it generally has the highest moisture capacity. Equilibration can be verified by placing the desiccant in a sealed container (such as a bottle) within the environmental chamber and measuring the relative humidity in the bottle with a hygrometer [316]. A supplemented phase diagram can be used to choose moisture equilibration parameters, as discussed later in this chapter.
Pitfalls and Practical Solutions
Published in Joseph Chamberlain, The Analysis of Drugs in Biological Fluids, 2018
Traces of water can be removed from organic phase by the adding a pinch of anhydrous sodium sulfate. Even visible amounts of water can be mopped up by this reagent and the dried solvent can be readily poured off, the hydrated salt sticking in clumps to the sides of the vessel. Alternatively the organic extract can be simply filtered through anhydrous sodium; if there are only trace amounts of water, simply passing the phase through dry filter paper will be adequate with less potential of losing drug by adsorption to the solid salt. For example, calcium chloride added to the extract was shown to cause loss of oxprenolol in an assay for this compound.1406 Immediate storage of dried-down samples in a desiccator is recommended to remove last traces of water or to preserve the anhydrous condition of samples. Reid1407 suggests that silica gel, rather than phosphorous pentoxide, should be used as a desiccant; the latter reagent will overdry the atmosphere and cause volatilization of drug from the sample. A similar effect may also be noted in freeze-drying procedures; during the process of freeze-drying the sample will remain cold, but if the process is allowed to continue after the water has been removed, the temperature of the sample will rise to ambient and loss of sample may occur.1408
Supercritical Fluid Extraction as a Sample Preparation Tool in Analytical Toxicology
Published in Steven H. Y. Wong, Iraving Sunshine, Handbook of Analytical Therapeutic Drug Monitoring and Toxicology, 2017
Robert J. Maxwell, Janet F. Morrison
Biological matrices, such as blood, urine, and tissues, generally must be desiccated and dispersed before SFE. Typically, these samples are mixed with an adsorbent such as sodium sulfate, magnesium sulfate, or Hydromatrix. There are advantages and limitations associated with the use of these adsorbents. For instance, sodium sulfate is a good desiccant; however, it may dissolve in the presence of large amounts of water. Magnesium sulfate has also been used as an SFE desiccant; however, it may bind too tightly to the sample matrix and thus restrict fluid flow. Hydromatrix, first reported as an SFE dispersing agent by Hopper and King62 in 1991, does not have these limitations. Hydromatrix is a pelletized form of diatomaceous earth that has a large surface area/volume (>200 m2/g). It reacts physically with water, rather than chemically like desiccants such as sodium sulfate. Hydromatrix is an inexpensive adsorbent, compared with some support materials, which is an important consideration when a large number of samples are routinely processed.
Dried blood spot sampling for therapeutic drug monitoring: challenges and opportunities
Published in Expert Review of Clinical Pharmacology, 2023
Isadora Ritter Müller, Gabriel Linden, Mariele Feiffer Charão, Marina Venzon Antunes, Rafael Linden
After collecting samples, it is recommended to dry them for at least 3 hours under ambient conditions, while avoiding direct sunlight [1]. The DBS drying time has to be tested during method development, so that, longer drying times could be required, but also shorter drying times could be sufficient. Additionally, it is important to store the dried samples with a desiccant to remove additional water. Residual humidity can lead to bacterial or fungal growth and alter the elution time of the specimen, depending on the ambient temperature and humidity, sample volume, and type of filter paper used. In addition, humidity may produce a bias in DBS sample quantification, as water would dilute the analytes. Therefore, the required drying time may vary and should be adjusted accordingly. Some studies have reported drying times ranging from 10 minutes to several days, including overnight drying [7]. Of note, data on the minimum time needed for drying are limited, as the different drying times are frequently not tested.
PLGA-modified Syloid®-based microparticles for the ocular delivery of terconazole: in-vitro and in-vivo investigations
Published in Drug Delivery, 2022
Nada Zaghloul, Azza A. Mahmoud, Nermeen A. Elkasabgy, Nada M. El Hoffy
Mesoporous silica has proved its potentiality to improve the poor aqueous solubility of many pharmaceutical moieties (Choudhari et al., 2014). As a drug carrier system, mesoporous silica can be loaded with drugs utilizing different techniques among which are the solvent immersion employing organic solvents as well as incipient wetness impregnation or melting in (Xu et al., 2013). Moreover, the safety and biocompatibility of the ocular use for mesoporous silica have been assessed (Sun et al., 2020). Amongst the pre-synthesized mesoporous silica carriers that are gaining much attention these days are the Syloids®. Syloid® 244 FP is a micronized (diameter 2.5–3.7 μm) artificial amorphous silica particles with highly developed network of non-ordered mesopores, that provide the advantage of having large surface area (Limnell et al., 2011). The pharmaceutical roles of these silicas as excipients include their use as glidants, adsorbents, anti-tacking and desiccant agents, carriers for active pharmaceutical ingredients as well as thickening and gelling agents (Kinnari et al., 2011; Chaudhari & Gupte, 2017; Donnadio et al., 2019).
Design of experiments and multivariate analysis approach to study dissolution stability of a modified-release drug product to support lean design strategies
Published in Drug Development and Industrial Pharmacy, 2021
Nika Jordan, Robert Roškar, Iztok Grabnar
Accelerated stability study enabled us to indicate the SLLAs and some SRQAs that could directly or indirectly influence the stability of the drug product. The stability data from 40 °C/75% RH storage condition showed that the drug substance of the MR drug product is chemically very stable and no significant degradation occurred after exposing the drug product to accelerated storage condition. Water activity trend corresponded to the continuous permeation of moisture through the packaging container. Release samples were measured after manufacturing, stored in a glass vial for the time of the analyses. Moisture sorption capacity of the desiccant reduced the relative humidity inside the packaging. Water activity values at accelerated conditions were well below the acceptance criteria NMT 0.7 at all packaging forms. On that note, Water activity was not recognized as SLLA. However, high water content can accelerate the degradation mechanism, suggesting it can be critical for the long-term stability of the matrix system and dissolution properties because of potential degradation of PEO and is an indirect SRQA. High Water activity could also be a risk for product quality, however impurities were mostly below QL 0.05%.