A practical reference on Karl Fischer titration: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-01-31. Anything still debated is marked as such rather than presented as settled.
Storage conditions depend on the formulation and the intended shelf life. Many pharmaceutical and biological freeze-dried products are kept at 2–8 °C, while some stable foods and reagents tolerate room temperature. Others require −20 °C or colder to slow chemical degradation or aggregation. Protection from light and oxygen is common because oxidation can continue in the dry state. Stability studies usually monitor potency, appearance, moisture, and reconstitution time over months or years. Predictions from accelerated studies are useful but may not fully capture real-time changes.
Quality control for freeze-dried lots combines visual inspection with instrumental tests. Cake appearance, color, and shrinkage are recorded against a reference, while residual moisture is measured by Karl Fischer titration or loss on drying. Thermal analysis can reveal phase transitions and crystallization events, and X-ray diffraction distinguishes amorphous from crystalline solids. Microbiological tests and container closure integrity checks are also routine for sterile products. Analytical methods must be validated for the matrix, because excipients and low moisture can affect accuracy. Open questions include how best to predict long-term stability from short-term data.
Lyophilized solids are often hygroscopic, so handling occurs in controlled low-humidity areas or glove boxes when the material is exposed. Vials remain sealed with elastomeric stoppers and aluminum crimps until use, because airborne moisture can raise residual water and shorten shelf life. The porous cake is fragile and may crack, shrink, or powder during transport. Personnel typically avoid repeated warming and cooling of sealed units, which can draw moisture through closures. These practices aim to preserve the low water content achieved during drying.
Stability programs monitor lyophilized products under defined temperature and humidity conditions over time. Real-time studies at recommended storage conditions are the reference, while accelerated studies provide early signals of degradation pathways. Because a dry cake can still undergo oxidation, hydrolysis, or aggregation, stability depends on residual moisture, excipients, and container headspace. Open questions include how best to predict long-term stability from short accelerated runs and how vial-to-vial variability affects shelf life. Current guidance treats these predictions as product-specific rather than universally generalizable.
Freeze-dried materials are hygroscopic to varying degrees and can take up moisture after drying. Storage therefore often uses sealed glass vials, rubber stoppers, and crimp seals to limit contact with ambient humidity. A desiccant may be included for moisture-sensitive products, although it is not universal. Controlled room temperature is sufficient for many lyophilizates, while others require refrigeration or freezing. Moisture ingress remains a primary cause of cake collapse, chemical degradation, and loss of reconstitution performance.
Quality assessment of a lyophilized product includes cake appearance, residual moisture, reconstitution time, and container closure integrity. A uniform, porous cake suggests that freezing and drying stayed within the formulation's design space. Cracks, shrinkage, meltback, or a glassy film can indicate thermal abuse or a formulation problem. Analysts also test for subvisible particles and sterility when the product requires those specifications. Visual inspection alone cannot confirm biological activity or chemical stability, so it is combined with analytical methods.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | 2–8 °C | Some products tolerate room temperature or require −20 °C. |
| Residual moisture method | Karl Fischer titration | Coulometric or volumetric; specific for water. |
| Cake appearance | Uniform porous plug | Collapse, shrinkage, or meltback indicates process deviation. |
| Reconstitution time | Seconds to several minutes | Depends on cake porosity, diluent, and formulation. |
| Primary container | Glass vial with elastomeric stopper | Crimp seal limits moisture ingress. |
Misconceptions about lyophilization include the idea that dried products are indefinitely stable or that vacuum sealing eliminates all degradation. Chemical reactions can continue in the solid state, and some proteins lose activity even at low moisture. Another misconception is that any freeze-dryer cycle can be scaled by time alone; heat and mass transfer differ with equipment and load. Open questions remain about predicting long-term stability from short accelerated studies, particularly for amorphous formulations. Real-time stability data remain the standard for shelf-life assignment.
After lyophilization, the dried product is often sealed under vacuum or an inert gas to limit moisture and oxygen exposure. Vials, stoppers, and seals must maintain their barrier throughout shelf life. Storage temperature depends on product sensitivity: some cakes tolerate controlled room temperature, while labile biologics require refrigeration. Humidity is a critical variable because dried cakes are hygroscopic and can absorb water when exposed to air. Handling procedures therefore limit open-vial time and use desiccated environments for sampling.
Regulatory expectations for lyophilized products focus on consistent manufacture and documented stability. Batches are often monitored for moisture, appearance, potency, and sterility where applicable. Process parameters such as shelf temperature, chamber pressure, and drying time are recorded and controlled within validated ranges. Open questions remain about how best to predict long-term stability from short accelerated studies, especially for complex biologics. Variations in freezing rate and ice crystal size can produce differences that are not always visible but may affect performance.
After drying, a lyophilized product is usually sealed under vacuum or an inert gas to limit moisture uptake. Residual water content is measured because small changes can alter chemical stability and cake appearance. Storage temperature depends on the material; many biological products are kept at 2–8 °C, while some require −20 °C or colder. Exposure to ambient humidity during handling can cause the porous solid to absorb water and collapse. Container closures and stoppers are therefore selected for low moisture transmission and compatibility.
Quality control for lyophilized materials includes visual inspection of the cake, measurement of residual moisture, and tests for reconstitution time. An acceptable cake is typically uniform and may be slightly porous; shrinkage, meltback, or cracks can indicate process deviations. Analytical methods such as Karl Fischer titration, thermogravimetric analysis, and near-infrared spectroscopy quantify water content. Reconstitution time is recorded because a very slow or incomplete dissolution can signal collapse or aggregation. Stability studies compare samples stored under defined temperature and humidity conditions over months or years.
Stability of a lyophilized solid depends on water content, temperature, and the physical state of the formulation. Amorphous products may slowly absorb moisture and drop below their glass transition temperature, causing collapse or crystallization. Some proteins and peptides can aggregate even in a dry state, especially when exposed to heat or moisture. Accelerated stability studies at elevated temperature and humidity help estimate shelf life, but real-time data remain the basis for expiration dating.
After drying, a lyophilized product is usually sealed under vacuum or an inert gas to limit moisture and oxygen exposure. The container closure system matters because stoppers and seals can allow moisture ingress over time. Storage conditions are selected from stability studies that track potency, cake appearance, and reconstitution behavior. Many freeze-dried materials are kept at controlled room temperature, while some require refrigeration or protection from light.
Quality control for freeze-dried forms includes visual inspection, water content measurement, and reconstitution time. A satisfactory cake is typically uniform, porous, and intact, although minor shrinkage or cracking may be acceptable if specifications allow. Karl Fischer titration, thermal gravimetric analysis, and near-infrared spectroscopy are used to measure water content. Reconstitution is assessed by adding a specified diluent and recording the time and ease of dissolution. Microbiological and particulate tests are added when the product is sterile or intended for injection.
Infrared spectroscopy is a sensitive probe for the presence of bridging carbonyl ligands. For compounds with doubly bridging CO ligands, denoted μ2-CO or often just μ-CO, the bond stretching frequency νCO is usually shifted by 100–200 cm−1 to lower energy compared to the signatures of terminal CO, which are in the region 1800 cm−1. Bands for face-capping (μ3) CO ligands appear at even lower energies. In addition to symmetrical bridging modes, CO can be found to bridge asymmetrically or through donation from a metal d orbital to the π* orbital of CO. The increased π-bonding due to back-donation from multiple metal centers results in further weakening of the C–O bond.
General xenobiochemistry, including in vitro studies concerned with the metabolism, disposition and excretion of drugs, and other xenobiotics, as well as the structure, function and regulation of associated enzymes Clinical pharmacokinetics and metabolism, covering the pharmacokinetics and absorption, distribution, metabolism and excretion of drugs and other xenobiotics in man. Animal pharmacokinetics and metabolism, covering the pharmacokinetics, and absorption, distribution, metabolism and excretion of drugs and other xenobiotics in animals. Pharmacogenetics, defined as the identification and functional characterisation of polymorphic genes that encode xenobiotic metabolising enzymes and transporters that may result in altered enzymatic, cellular and clinical responses to xenobiotics. Molecular toxicology, concerning the mechanisms of toxicity and the study of toxicology of xenobiotics at the molecular level. Topics in xenobiochemistry, in the form of reviews and commentaries are primarily intended to be a critical analysis of the issue, wherein the author offers opinions on the relevance of data or of a particular experimental approach or methodology. According to the Journal Citation Reports, the journal received a 2014 impact factor of 2.199, ranking it 134th out of 254 journals in the category Pharmacology & Pharmacy and 50th out of 87 journals in the category Toxicology. The editor in chief is Costas Ioannides (University of Surrey).
=== Names === Enobosarm is the generic name of the drug and its International Nonproprietary Name (INN). Ostarine was a tentative brand name of the drug created by GTx, Inc. that did not end up being used for marketing purposes but continues to be used as a synonym for the drug. Enobosarm is also known by the pharmaceutical developmental code names S-22 (synthesis paper), GTx-024 (GTx, Inc.), MK-2866 (Merck), and VERU-024 (Veru, Inc.).
== Hydrodynamic CCC == The modern era of CCC began with the development of the planetary centrifuge by Dr. Yoichiro Ito which was first introduced in 1966 as a closed helical tube which was rotated on a "planetary" axis as is turned on a "sun" axis. A flow-through model was subsequently developed and the new technique was called countercurrent chromatography in 1970. The technique was further developed by employing test mixtures of DNP amino acids in a chloroform:glacial acetic acid:0.1 M aqueous hydrochloric acid (2:2:1 v/v) solvent system. Much development was needed to engineer the instrument so that required planetary motion could be sustained while the phases were being pumped through the coil(s). Parameters such as the relative rotation of the two axes (synchronous or non-synchronous), the direction of flow through the coil, and the rotor angles were investigated.
In soil, microorganisms that reside in the rhizosphere (a zone that includes the root surface and the soil that adheres to the root after gentle shaking) carry out nitrogen fixation, converting nitrogen gas to nitrogenous compounds. This serves to provide an easily utilisable form of nitrogen for many plants, which cannot fix nitrogen themselves. Many other bacteria are found as symbionts in humans and other organisms. For example, the presence of over 1,000 bacterial species in the normal human gut flora of the intestines can contribute to gut immunity, synthesise vitamins, such as folic acid, vitamin K and biotin, convert sugars to lactic acid (see Lactobacillus), as well as fermenting complex undigestible carbohydrates. The presence of this gut flora also inhibits the growth of potentially pathogenic bacteria (usually through competitive exclusion) and these beneficial bacteria are consequently sold as probiotic dietary supplements. Nearly all animal life is dependent on bacteria for survival as only bacteria and some archaea possess the genes and enzymes necessary to synthesise vitamin B12, also known as cobalamin, and provide it through the food chain. Vitamin B12 is a water-soluble vitamin that is involved in the metabolism of every cell of the human body. It is a cofactor in DNA synthesis and in both fatty acid and amino acid metabolism. It is particularly important in the normal functioning of the nervous system via its role in the synthesis of myelin.
Sources: en.wikipedia.org
SEC is used primarily for the analysis of large molecules such as proteins or polymers. SEC works by trapping smaller molecules in the pores of the adsorbent ("stationary phase"). This process is usually performed within a column, which typically consists of a hollow tube tightly packed with micron-scale polymer beads containing pores of different sizes. These pores may be depressions on the surface or channels through the bead. As the solution travels down the column some particles enter into the pores. Larger particles cannot enter into as many pores. The larger the particles, the faster the elution. The larger molecules simply pass by the pores because those molecules are too large to enter the pores. Larger molecules therefore flow through the column more quickly than smaller molecules, that is, the smaller the molecule, the longer the retention time. One requirement for SEC is that the analyte does not interact with the surface of the stationary phases, with differences in elution time between analytes ideally being based solely on the solute volume the analytes can enter, rather than chemical or electrostatic interactions with the stationary phases. Thus, a small molecule that can penetrate every region of the stationary phase pore system can enter a total volume equal to the sum of the entire pore volume and the interparticle volume. This small molecule elutes late (after the molecule has penetrated all of the pore- and interparticle volume—approximately 80% of the column volume).
== Terminology and definition == The term fungarium was introduced by Brian Spooner and Paul Cannon and presented by David Hawksworth in 2010 as a logical analogue to herbarium for collections of preserved fungi. Historically, mycology was treated as a sub-discipline of botany, so fungal specimens were commonly stored within herbaria. The proposal of fungarium formed part of a broader assertion of mycological independence; a related development is the use of "funga" for the fungi of a particular area, in parallel with "flora" for plants and "fauna" for animals. Hawksworth recommended fungarium for facilities whose taxonomic value centres on representative members of the Fungi, although many institutions have continued to use "herbarium" for historical reasons or for combined botanical-mycological collections. The term gained wider professional use when the Royal Botanic Gardens, Kew adopted it for its mycological collection. While some institutions use the term to explicitly distinguish mycological holdings from plant collections, others maintain the name "herbarium" for historical continuity. Similarly, the term "lichenarium" is occasionally used by institutions that maintain separate collections of lichen specimens. In scientific usage, a fungarium is centred on preserved fungal material, usually dried tissue such as whole reproductive structures or representative parts, though it may also include permanent microscope slides and, more rarely, specimens preserved in liquid.
== History == Electron-capture dissociation (ECD) was developed in 1998 to fragment large proteins for mass spectrometric analysis. Because ECD requires a large amount of near-thermal electrons (<0.2eV), originally it was used exclusively with Fourier transform ion cyclotron resonance mass spectrometry (FTICR), the most expensive form of MS instrumentation. Less costly options such as quadrupole time-of-flight (Q-TOF), quadrupole ion trap (QIT) and linear quadrupole ion trap (QLT) instruments used the more energy-intensive collision-induced dissociation method (CID), resulting in random fragmentation of peptides and proteins. In 2004 Syka and Coon et al. announced the creation of ETD, a dissociation method similar to ECD, but using a low-cost, widely available commercial spectrometer. The first ETD experiments were run on a QLT mass spectrometer with an electrospray ionization (ESI) source.
An extremely important application of serum S100B testing is in the selection of patients with minor head injury who do not need further neuroradiological evaluation, as studies comparing CT scans and S100B levels have demonstrated S100B values below 0.12 ng/mL are associated with low risk of obvious neuroradiological changes (such as intracranial hemorrhage or brain swelling) or significant clinical sequelae. The excellent negative predictive value of S100B in several neurological conditions is due to the fact that serum S100B levels reflect blood–brain barrier permeability changes even in absence of neuronal injury. In addition, S100B, which is also present in human melanocytes, is a reliable marker for melanoma malignancy both in bioptic tissue and in serum.
== Biosynthesis == The biosynthesis of eugenol begins with the amino acid tyrosine. L-tyrosine is converted to p-coumaric acid by the enzyme tyrosine ammonia lyase (TAL). From here, p-coumaric acid is converted to caffeic acid by p-coumarate 3-hydroxylase using oxygen and NADPH. S-Adenosyl methionine (SAM) is then used to methylate caffeic acid, forming ferulic acid, which is in turn converted to feruloyl-CoA by the enzyme 4-hydroxycinnamoyl-CoA ligase (4CL). Next, feruloyl-CoA is reduced to coniferyl aldehyde by cinnamoyl-CoA reductase (CCR). Coniferyl aldehyde is then further reduced to coniferyl alcohol by cinnamyl-alcohol dehydrogenase (CAD) or sinapyl-alcohol dehydrogenase (SAD). Coniferyl alcohol is then converted to an ester in the presence of the substrate CH3COSCoA, forming coniferyl acetate. Finally, coniferyl acetate is converted to eugenol via the enzyme eugenol synthase 1 and the use of NADPH. Eugenol is a metabolite of caleicine, the active compound found in Calea ternifolia, and is thought to cause the sedative and hallucinogenic state C. ternifolia can induce.
Sources: en.wikipedia.org
Francis Joseph Donnelly. For services to Disability Sport and to the community in Northern Ireland. Nilesh Bhasker Dosa. Founder, icanyoucantoo. For services to Social Equality. George David Dowell. Owner, Worthing Football Club. For services to Association Football and to Disability Awareness. Elissa Rebecca Louise Downie. For services to Gymnasts and to the Sport of Gymnastics. Rebecca Lauren Downie. For services to Gymnasts and to the Sport of Gymnastics. Spencer Drury. Lately Councillor, Royal Borough of Greenwich. For Political and Public Service. James Michael Duffy. Lately Child Protection Manager, Lothian and Borders Police and Police Service of Scotland. For services to Children. Giles Duley. Founder, Legacy of War Foundation. For services to Survivors of Conflict. Mary Alexandra Earps. For services to Association Football. Dr. Gillian Mary Eatough. Lately Chief Executive Officer, Learning Community Trust. For services to Education. Captain Thomas David Eccles. Fisheries Officer, Department of Agriculture, Environment and Rural Affairs. For services to Fisheries, Environment and to Maritime Safety. Linda Jacqueline Edmunds. Consultant Nurse, Heart Failure and Cardiac Rehabilitation, Aneurin Bevan University Health Board. For services to Cardiac Rehabilitation and Heart Failure. Professor Anthony David Edwards. Professor of Paediatrics and Neonatal Medicine, King's College London. For services to Health Research. Huw William Edmond Edwards. Founder Member, Monmouth Male Voice Choir. For services to Music and to Charity. Dr. Alice Elizabeth Ellis (Alice Hartley).
== Operations == JEOL Ltd. has four business segments. Electron Optics manufactures scanning electron microscopes, transmission electron microscopes and scanning probe microscopes, along with related equipment. The Analytical Instruments section's products include mass spectrometers, nuclear magnetic resonance and electron spin resonance equipment. The Industrial Equipment segment covers a range of equipment particularly targeted at the semiconductor industry, such as electron beam sources, wafer process monitors, and plasma gun series. Finally, the Medical Equipment segment manufactures automatic analysis devices, clinical diagnostic systems and amino acid analyzers.
, the disease decays and fades away over time. Using the differential equations of the SIR model and converting them to numerical discrete forms, one can set up the recursive equations and calculate the S, I, and R populations with any given initial conditions but accumulate errors over a long calculation time from the reference point. Sometimes a convergence test is needed to estimate the errors. Given a set of initial conditions and the disease-spreading data, one can also fit the data with the SIR model and pull out the three reproduction numbers when the errors are usually negligible due to the short time step from the reference point. Any point of the time can be used as the initial condition to predict the future after it using this numerical model with assumption of time-evolved parameters such as population,
=== Therapeutics === Because it is abundant, of human origin, and easy to grow, L. plantarum has been tested for health effects. It has been identified as a probiotic, which suggests its value for further research and application. L. plantarum has significant antioxidant activities and also helps to maintain intestinal permeability. It is able to suppress the growth of gas-producing bacteria in the intestines and may benefit some patients who suffer from IBS. It helps to create microbe balance and stabilize digestive enzyme patterns. Lactiplantibacillus plantarum has been found in experiments to increase hippocampal brain derived neurotrophic factor, which means L. plantarum may have a beneficial role in the treatment of depression. The ability of L. plantarum to survive in the human gastro-intestinal tract makes it a possible in vivo delivery vehicle for therapeutic compounds or proteins. Lactiplantibacillus plantarum is a constituent in VSL#3. This proprietary, standardized formulation of live bacteria may be used in combination with conventional therapies to treat ulcerative colitis and requires a prescription.
under the joint auspices of the George Washington University and the Carnegie Institution of Washington. There, the news on nuclear fission was spread even further, which fostered many more experimental demonstrations. The 6 January 1939 Hahn and Strassman paper announced the discovery of fission. In their second publication on nuclear fission in February 1939, Hahn and Strassmann used the term Uranspaltung (uranium fission) for the first time, and predicted the existence and liberation of additional neutrons during the fission process, opening up the possibility of a nuclear chain reaction. The 11 February 1939 paper by Meitner and Frisch compared the process to the division of a liquid drop and estimated the energy released at 200 MeV. The 1 September 1939 paper by Bohr and Wheeler used this liquid drop model to quantify fission details, including the energy released, estimated the cross section for neutron-induced fission, and deduced 235U was the major contributor to that cross section and slow-neutron fission.
Sources: en.wikipedia.org
Karl Fischer titration is widely used because it is specific for water and works at low levels. Loss on drying is simpler but less specific, since volatile solvents or decomposition products can also be lost.
Collapse can occur when the product temperature exceeds its critical formulation temperature during drying. The porous structure then melts or shrinks, reducing reconstitution speed and sometimes altering stability.
No. Low moisture slows many degradation pathways but does not stop oxidation, hydrolysis, or physical changes completely. Storage temperature, container closure, and formulation still influence shelf life.
Many dried cakes are hygroscopic and can adsorb water during storage or handling. Absorbed moisture may lower the glass transition temperature and promote chemical reactions. Sealed packaging and controlled humidity reduce this risk.