Everything below concerns Sublimation. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-03-14. Numbers and descriptions here follow the published literature rather than marketing material.
Lyophilization removes water from a frozen material by sublimation under reduced pressure. The process begins with freezing, which converts liquid water into ice and fixes the structure of the sample. After freezing, primary drying lowers pressure so ice changes directly to vapor without passing through a liquid phase. Secondary drying then removes bound water that remains after ice sublimation. The result is a dry, porous solid that often retains its original shape.
The low pressure used during drying allows water vapor to move from the ice surface to a cold condenser. Energy supplied as heat drives sublimation but must stay below the collapse temperature of the frozen matrix. If the product becomes too warm, the frozen structure may soften or melt, reducing pore formation and slowing drying. Formulations often include bulking agents, stabilizers, or buffers to support a rigid cake. The final moisture content depends on formulation, freezing rate, and the length of secondary drying.
Quality control for lyophilized materials includes visual inspection, residual moisture measurement, and reconstitution testing. Cake appearance can reveal process problems such as collapse, shrinkage, or meltback, although appearance alone does not prove potency. Residual moisture is commonly measured by Karl Fischer titration or by loss on drying. Reconstitution time is checked because a slow or incomplete dissolve can indicate a change in pore structure. Stability studies track these attributes over time under defined temperature and humidity conditions.
Analytical methods for lyophilized solids must account for the low moisture content and the fragile cake. Karl Fischer titration is widely used for water content, while near-infrared spectroscopy can measure moisture non-destructively in sealed containers. X-ray diffraction and modulated differential scanning calorimetry help identify crystalline or amorphous phases. Residual solvent analysis may be needed if organic solvents were used during formulation. The combination of these methods supports batch release and long-term stability assessment.
| Property | Value | Notes |
|---|---|---|
| Primary phase change | Sublimation | Ice changes directly to vapor under reduced pressure |
| Typical chamber pressure | 0.01–0.5 mbar (1–50 Pa) | Below the triple point of water; product-specific |
| Typical product temperature during primary drying | −40 °C to −10 °C | Kept below collapse temperature |
| Typical residual moisture | 0.5–3% w/w | Target range varies by formulation and use |
| Common synonyms | Freeze-drying; lyophilisation | Lyophilization is the US spelling |
In practice, lyophilization is slower and more energy intensive than simple drying. Cycle times can range from hours to several days depending on load, container, and formulation. Amorphous materials may require excipients that help preserve structure during freezing and drying. The method is widely used for biological materials, pharmaceuticals, and foods where heat drying would cause unacceptable change. Open questions remain about scaling cycles between laboratory and production equipment, and this gap affects technology transfer.
Lyophilization removes water by freezing a material and then lowering pressure so ice changes directly to vapor. The process relies on sublimation, the phase transition from solid to gas without an intermediate liquid state. Because the material remains frozen during primary drying, the structure often stays porous. This porous matrix can rehydrate quickly when water is added back. The low pressure also allows vapor to leave the solid matrix without boiling.
A typical cycle begins with freezing, which fixes the material into a solid and determines ice crystal size. Primary drying then raises heat under vacuum so ice sublimes, often near or below the collapse temperature of the formulation. Secondary drying removes bound water that remains after ice is gone, usually by gently warming the product. Each stage balances heat input against pressure to avoid melting or structural damage. Temperature probes and pressure sensors guide the transition between stages.
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.
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.
== Monoprotic and polyprotic bases == Bases with only one ionizable hydroxide (OH−) ion per formula unit are called monoprotic since they can accept one proton (H+). Bases with more than one OH- per formula unit are polyprotic. The number of ionizable hydroxide (OH−) ions present in one formula unit of a base is also called the acidity of the base. On the basis of acidity bases can be classified into three types: monoacidic, diacidic and triacidic.
Similarly to the findings with a strong CYP2D6 inhibitor, a pharmacogenomic clinical study with LSD found that LSD levels were 75% higher in people with non-functional CYP2D6 (poor metabolizers) compared to those with functional CYP2D6. Serotonin syndrome can be caused by combining psychedelics with other serotonergic drugs, including certain antidepressants, opioids, psychostimulants (e.g. MDMA), serotonin 5-HT1 receptor agonists (e.g. triptans), herbs or supplements, and others. However, there is said to be no risk of serotonin syndrome when psychedelics like LSD or psilocybin are taken while on SSRIs. The same is not true of ayahuasca, as ayahuasca also contains harmala alkaloids which act as MAOIs and can produce life-threatening serotonin toxicity when combined with SSRIs. A high rate of seizures has been reported when people on lithium have taken serotonergic psychedelics. In an analysis of online reports, 47% of 62 accounts reported seizures when a psychedelic was taken while on lithium. The mechanism of this interaction is unclear.
The history of penicillin traces how observations of antibiotic activity in the mould Penicillium led to the development of penicillins, a family of widely used antibiotics. Ancient societies used moulds to treat infections, and many people observed the inhibition of bacterial growth by moulds. While working at St Mary's Hospital in London in 1928, Scottish physician Alexander Fleming was the first to show experimentally that a Penicillium mould secretes an antibacterial substance, which he named "penicillin". The mould was found to be a variant of Penicillium chrysogenum (now called Penicillium rubens), a contaminant of a bacterial culture in his laboratory. The work on penicillin at St Mary's ended in 1929. In 1939, a team of scientists at the Sir William Dunn School of Pathology at the University of Oxford, led by Howard Florey, which included Edward Abraham, Ernst Chain, Mary Ethel Florey, Norman Heatley and Margaret Jennings, began researching penicillin. They developed a method for cultivating the mould and extracting, purifying and storing penicillin from it, together with an assay for measuring its purity. "Penicillin" now became the name of the active ingredient in the mould juice. They carried out experiments on animals to determine penicillin's safety and effectiveness before conducting clinical trials and field tests. They derived penicillin's chemical formula and determined how it works. The private sector and the United States Department of Agriculture located and produced new strains and developed mass production techniques.
== Further reading == A century of enduring beauty: Cold Spring Granite Company. Cold Spring Granite. 2002. OCLC 51553279. Gross, Stephen J. (2001). "The Battle over the Cold Spring Dam: Farm-Village Conflict and Contested Identity among Rural German Americans". Journal of American Ethnic History. 21 (1): 83–117. doi:10.2307/27502780. JSTOR 27502780. S2CID 254487944. Gross, Stephen (2006). "The Grasshopper Shrine at Cold Spring, Minnesota: Religion and Market Capitalism among German-American Catholics". The Catholic Historical Review. 92 (2): 215–243. doi:10.1353/cat.2006.0133. JSTOR 25027056. S2CID 159890053. Gross, S. J. (March 1, 2012). "The Not-So-Great Cat Massacre: An Episode in American Catholic History". Journal of Social History. 45 (3): 780–808. doi:10.1093/jsh/shr100. Gross, Stephen J. (2004). "'Perils of Prussianism': Main Street German America, Local Autonomy, and the Great War". Agricultural History. 78 (1): 78–116. doi:10.1215/00021482-78.1.78. JSTOR 3745091. S2CID 247829597. Roscoe, John; Roscoe, Robert; Ohman, Doug (2009). Legacies of faith: the Catholic churches of Stearns County. North Star Press of St. Cloud. ISBN 978-0-87839-314-5. OCLC 319491118. Amid hills of granite, a spring of faith: a history of Saint Boniface Parish, Cold Spring, Minnesota, 1878-1978. Cold Spring Record. 1978. OCLC 10725924.
Sources: en.wikipedia.org
== Fluoroalkenes and fluoroalkynes == Unsaturated fluorocarbons are far more reactive than fluoroalkanes. Although difluoroacetylene is unstable (as is typical for related alkynes, see dichloroacetylene), hexafluoro-2-butyne and related fluorinated alkynes are well known.
== Awards and recognition == Eberlin was named among the Forbes "30 Under 30" list in 2015. She won the Marion Milligan Mason Award of the American Association for the Advancement of Science in 2016. The award is given every two years to promising young female researchers in chemistry. She won the MacArthur "Genius" Fellowship from the John D. and Catherine T. MacArthur Foundation in 2018 for her research on the use of mass spectrometry "to differentiate more quickly and accurately diseased from healthy tissues during surgery". She is the first UT Austin professor to win MacArthur grant this century. The award consists of a $625,000 no-strings-attached grant. According to the foundation, this award goes to "extraordinarily talented and creative individuals as an investment in their potential". She also won the Moore Inventor Fellowship in 2018. She received the 2020 Curt Brunnée Award from the International Mass Spectrometry Foundation. She was named on the Power List by the Analytical Scientist in 2014, 2018, 2019, 2021, 2022, 2023, and 2024. She received the 2024 Norman Hackerman Award from the Welch Foundation and the Biemann Medal from the American Society for Mass Spectrometry in 2025.
== Function == Nicotinamide phosphoribosyltransferase (iNAMPT) catalyzes the condensation of phosphoribosyl pyrophosphate with nicotinamide (NAM) to yield nicotinamide mononucleotide (NMN) and pyrophosphate (PPi). This is the first step in the biosynthesis of nicotinamide adenine dinucleotide (NAD+). This reaction allows a salvage pathway, in which NAM is recycled from enzymes that use NAD+ (sirtuins, PARPs, CD38) as these produce NAM as a waste product. Thus this reaction is a major source of NAD+ production in the body. De novo synthesis of NAD+ from tryptophan occurs only in the liver and kidney, overwhelmingly in the liver.
== Side effects == Loxapine can cause side effects that are generally similar to that of other antipsychotic medications. These include, e.g., gastrointestinal problems (like constipation and abdominal pain), cardiovascular problems (like tachycardia), moderate likelihood of drowsiness (relative to other antipsychotics), and movement problems (i.e. extrapyramidal symptoms [EPS]). At lower dosages its propensity for causing EPS appears to be similar to that of atypical antipsychotics. Although it is structurally similar to clozapine, it has much lower risk of agranulocytosis (which, even with clozapine, is 0.8%); however, mild and temporary fluctuations in blood leukocyte levels can occur. Abuse of loxapine has been reported. The inhaled formulation of loxapine carries a low risk for a type of airway adverse reaction called bronchospasm that is not thought to occur when loxapine is taken by mouth.
She also created the Nutshell Studies of Unexplained Death, intricate crime scene dioramas used to train investigators, which are still in use today. Mary Louisa Willard, a chemistry professor at Pennsylvania State University (Penn State) from the 1920s through early 1960s, used her expertise in microscopy and chemical forensics to assist local and international criminal investigations.
Sources: en.wikipedia.org
Lyophilization relies on sublimation, so water moves from solid ice to vapor without becoming liquid. The material is frozen, pressure is reduced, and controlled heat is supplied. Vapor is captured on a cold condenser, leaving a dry porous solid.
The process has three main stages: freezing, primary drying, and secondary drying. Freezing sets the ice structure, primary drying removes free ice, and secondary drying removes bound water. Each stage uses specific temperature, pressure, and time settings.
No, it is a drying method rather than a sterilization method. Removing water can limit microbial growth, but it does not reliably kill microorganisms. Sterility must come from separate steps such as filtration, heat treatment, or aseptic processing.
Most lyophilized products are stored in sealed containers at controlled temperature and humidity. Some require refrigeration, while others are stable at room temperature. Protection from light and moisture is often necessary.