Eutectic temperature comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-01-19. Numbers and descriptions here follow the published literature rather than marketing material.
A freeze-dryer consists of a vacuum chamber, temperature-controlled shelves, a condenser, and a vacuum pump. Vials, ampoules, or bulk trays hold the product during the cycle. The condenser traps water vapor as ice at a temperature lower than the product. Cycle development balances shelf temperature, chamber pressure, and time. Scale-up can be difficult because heat and mass transfer change with equipment size, so process analytical tools and conservative validation are often used.
Lyophilization is a dehydration technique in which a product is frozen and the solvent is removed under reduced pressure. The low pressure allows ice to sublimate directly into vapor without passing through a bulk liquid phase. This differs from conventional drying, where heat drives evaporation and can damage heat-sensitive structures. The process is used for biological materials, pharmaceutical formulations, and some foods. Its main advantage is preservation of porous structure and rapid reconstitution.
Freezing is the first stage and sets the ice structure that later becomes the pore network. The formulation is cooled below its freezing point, often with a controlled ramp, and solutes concentrate as ice forms. Primary drying then lowers chamber pressure and supplies heat to sublime the ice. The product temperature must stay below its collapse or eutectic temperature to prevent structural loss. Secondary drying raises the temperature modestly to remove bound water and achieve a low residual moisture.
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.
Freeze-drying is distinct from simple evaporation and from spray drying. Evaporation removes water at temperatures above freezing, while spray drying rapidly dries droplets in a heated gas stream. Lyophilization avoids high temperatures, which can be useful for heat-sensitive materials such as proteins, vaccines, and some foods. The porous cake produced by sublimation dissolves or rehydrates more quickly than a dense dried mass. Not all materials tolerate freezing or the pH shifts that can occur as solutes concentrate during ice formation.
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.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | freeze-drying, lyophilisation, cryodesiccation | Lyophilization is common in pharmaceutical literature. |
| Typical chamber pressure during primary drying | 0.05–0.5 mbar (5–50 Pa) | Must remain below the triple point of water. |
| Typical shelf temperature during freezing | −40 to −20 °C | Lower temperatures may be used for eutectic systems. |
| Typical residual moisture after secondary drying | 0.5–3% w/w | Product-dependent; low moisture improves stability but can cause over-drying. |
| Typical analytical method for residual moisture | Karl Fischer titration or loss on drying | Thermogravimetric methods are also used. |
Secondary drying removes bound water that remains after ice sublimation. Shelf temperature is raised gradually while pressure remains low, reducing water content to a target range. Over-drying can cause brittleness or electrostatic issues, while under-drying affects stability. The endpoint is often judged by pressure rise tests, temperature measurements, or water content analysis. Scale-up depends on matching heat and mass transfer across equipment sizes. Small changes in shelf temperature or pressure can alter cycle length substantially.
Lyophilization, or freeze-drying, removes water from a material by freezing it and then lowering pressure so ice changes directly to vapor. The process relies on sublimation, the phase transition from solid to gas without an intervening liquid state. It is used for heat-sensitive materials that would degrade in conventional drying. The three stages are freezing, primary drying, and secondary drying, each with distinct temperature and pressure requirements. In practice, cycle design balances these variables.
The physical chemistry of freezing influences whether a formulation forms an amorphous glass or a crystalline solid. Amorphous systems can collapse if product temperature rises above the glass transition temperature of the freeze concentrate. Crystalline systems may show eutectic melting, where ice and solute melt together at a fixed temperature. Formulators add bulking agents, lyoprotectants, and buffers to preserve structure and biological activity. The optimum cycle keeps product temperature below critical thresholds during primary drying while allowing efficient sublimation.
Lyophilization is a dehydration process that removes water from a frozen material by sublimation under low pressure. The material is first frozen so that water becomes ice; then the surrounding pressure is lowered below the vapor pressure of ice. Heat is applied gently so ice changes directly to vapor without passing through a bulk liquid phase. The vapor is collected on a cold condenser, leaving a dry porous matrix. This process differs from simple evaporation because the material remains frozen during the main drying stage.
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.
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.
Lyophilization is a drying process in which a solvent, usually water, is removed from a frozen material by sublimation under reduced pressure. The material is first solidified, then placed under vacuum so that ice transitions directly to vapor without a bulk liquid phase. This approach suits heat-sensitive substances that would degrade during conventional evaporation. Primary drying removes unbound ice, while secondary drying reduces water that remains adsorbed to the solid matrix. The result is a porous, lightweight solid that can be reconstituted later.
A typical cycle begins with freezing, sometimes including an annealing step to control ice crystal size. Freezing conditions influence the pore network that later allows vapor escape. During primary drying, shelf temperature and chamber pressure are set so heat enters the product while its temperature stays below the collapse or eutectic point. Secondary drying then raises the shelf temperature to desorb bound water and lower residual moisture. Cycle design depends on formulation, fill volume, container type, and equipment capability.
Vaginal films are soluble, thin sheets of medication that are inserted into the vagina where they dissolve and release the substances. Typical uses include delivery of contraceptive substances or antibiotics for infections. These films are inserted by simply pushing them into the vagina with one’s fingers. There they dissolve quickly upon interaction with natural vaginal fluids. Bioadhesives are substances that naturally stick to live tissue. Currently, studies are being done on bioadhesives adhering to cervical mucous membranes to allow for an extended release period. The drug would be released with mucus to create a localized treatment with high effectiveness. This is anticipated to be highly useful for treatment of cervical cancer. Bioadhesives can come in multiple forms, such as films, tablets, or gels. The appeal of bioadhesives is that they take advantage of the mucous environment surrounding the cervix and utilize it to benefit the drug delivery mechanism.
Cefpodoxime is an oral, third-generation cephalosporin antibiotic available in various generic preparations. It is active against both Gram-positive and Gram-negative organisms with notable exceptions including Pseudomonas aeruginosa, Enterococcus, and Bacteroides fragilis. It is typically used to treat acute otitis media, pharyngitis, sinusitis, and gonorrhea. It also finds use as oral continuation therapy when intravenous cephalosporins (such as ceftriaxone) are no longer necessary for continued treatment. Cefpodoxime inhibits peptidoglycan synthesis in bacterial cell walls. It has an oral bioavailability of approximately 50%, which is increased when taken with food. It has an elimination half-life of 2-3 hours in adults, which is prolonged in renal failure. Approved indications include community acquired pneumonia, uncomplicated skin and skin structure infections, and uncomplicated urinary tract infections. It was patented in 1980 and approved for medical use in 1989.
For example, Gioja (current Gioia Tauro), was fortified with city walls reinforced by watchtowers to defend against incursions. Several Calabrian cities such as Palmi (where the Saracen Tower stands) and Reggio Calabria were fortified with towers. Despite the heavy taxation and the growth of baronial power, the population remained loyal to the sovereign, seen as a defender of the poor people against the abuses of the powerful. In 1647–1648, exasperated by the excessive tax burden, people in Catanzaro stormed the offices of the tax collectors (arrendatori). The governor intervened and had the leaders of the revolt hanged, causing the rest to flee.
infection: tuberculosis, fungal infection, septic emboli neoplasm: e.g., metastases, lymphoma, hamartoma sarcoidosis alveolitis auto-immune disease: e.g., granulomatosis with polyangiitis, rheumatoid arthritis inhalation (e.g., pneumoconiosis)
Sources: en.wikipedia.org
=== Immune checkpoint inhibitors === Because of HLA-G's role in inhibiting NK cell responses in cancer, clinical immune checkpoint inhibitors targeting HLA-G have been designed. Tizona Therapeutics developed TTX-080, a monoclonal antibody targeting HLA-G's interaction with ILT2 and ILT4. In 2020, a phase 1a/1b trial began to assess safety and preliminary efficacy in multiple cancers. Early results showed activity in HPV-negative HNSCC and HER2-negative metastatic colorectal cancer with WT RAS/BRAF, leading to an expansion of the trial.
However, although the notion of obesity as a state of 'leptin resistance' has become ingrained in the minds of many researchers, data does not directly support this contention. For example, the work of Rudolph Leibel at Columbia University shows that, in both obese and lean individuals, leptin injections do not reduce body mass. The finding that both lean and obese subjects have a similar lack of response underscores the notion that the brain is not designed to respond to increased leptin by decreasing food intake; rather, lack of leptin acts as a signal to increase food intake. Indeed, Leibel's work has shown that the decreases in serum leptin that occur post-weight-loss constitute a state of leptin deficiency, which drives increased appetite with weight loss. As such, leptin injections in weight-reduced patients can prevent increases in appetite and thereby allow patients to maintain weight loss. These studies, therefore, demonstrate that leptin treatment may be a useful strategy to treat obesity in humans, if not by driving weight loss directly then by allowing weight loss (as a result of diet and exercise) to be more readily maintained. Moreover, as geneticists learn more from the few cases of leptin gene mutations, the possibility remains that, although leptin was ineffective at treating obesity across the population, some individual obese patients might still benefit from its use as an anti-obesity medication. Research into the adipose-derived hormones adiponectin and resistin is ongoing. Like leptin, these hormones also affect energy balance and metabolism.
Some crashed on flight decks, but the majority ditched into the sea. Some pilots intentionally went down in groups to facilitate rescue, and more ditched individually either in a controlled landing with a few gallons of fuel left or in a crash after their engines ran dry. Approximately three-quarters of the crews were rescued from the sea, either that night from crash locations within the task forces, or over the next few days for those further out, as search planes and destroyers criss-crossed the ocean looking for them.
For example, Pseudomonas sp which is incubated for 24days decomposed 59.1% and 67.6% of crude oil at 28 °C and 36 °C respectively. In the case of Bacillus sp, it broke down each 71.4% and 77.8% of crude oil at 28 °C and 36 °C. The lowest amount of crude oil was degraded at 44 °C by Pseudomonas sp and at 20 °C by Bacillus sp. Exposure of both bacteria to the crude oil at 28 °C for 14days showed a different level of BLCO degradation depending on pH level. At pH 7.0, the largest degree of crude oil degradation was seen by Bacillus sp, while Pseudomonas sp decayed BLCO the most at pH 7.4. After its peak decomposition of crude oil, the level of degradation decreased drastically no matter how high pH was. The abilities of decomposition differ but it has proved that some bacteria in soil are capable of biodegradation of bonny light oil. Therefore, those bacteria can contribute to purifying soil that are polluted by crude oil.
With a worldwide box-office gross of over $2.9 billion, Avatar is proclaimed to be the "highest-grossing" film, but such claims usually refer to theatrical revenues only and do not take into account home video and television income, which can form a significant portion of a film's earnings. Once revenue from home entertainment is factored in, it is not immediately clear which film is the most successful. Titanic earned $1.2 billion from video and DVD sales and rentals, in addition to the $2.2 billion it grossed in theaters. While complete sales data are not available for Avatar, it earned $345 million from the sale of sixteen million DVD and Blu-ray units in North America, and ultimately sold a total of thirty million DVD and Blu-ray units worldwide. After home video income is accounted for, both films have earned over $3 billion each. Television broadcast rights also substantially add to a film's earnings and, as of 2010, a film often earned the equivalent of as much as 20–25% of its theatrical box office for two television runs, on top of pay-per-view revenues; Titanic earned a further $55 million from the NBC and HBO broadcast rights, equating to about 9% of its North American gross. When a film is highly exploitable as a commercial property, its ancillary revenues can dwarf its income from direct film sales. The Lion King (1994) earned over $2 billion in box-office and home video sales, but this pales in comparison to the $8 billion earned at box offices around the world by the stage adaptation.
Sources: en.wikipedia.org
== Properties and applications == Cyclic peptides tend to be extremely resistant to the process of digestion, making them of interest to scientists working on novel oral medications. Examples include:
=== Discontinued === Amibegron (SR-58611; SR-58611A) – β3-adrenergic receptor agonist [26] BTG-1640 (ABIO-08/01; ABIO-0801) – undefined mechanism of action [27] Darigabat (CVL-865; PF-06372865; PF-6372865) – GABAA receptor positive allosteric modulator [28] Imagabalin (PD-0332334; PD-332334; PF-00195889) – α2δ subunit-containing voltage-gated calcium channel ligand [29] Naluzotan (PRX-00023) – serotonin 5-HT1A receptor agonist and sigma σ1 receptor agonist [30] Ocinaplon (CL-273547) – GABAA receptor positive allosteric modulator and nonbenzodiazepine/pyrazolopyrimidine [31] Pagoclone (IP-456; Panex; RP-62955) – GABAA receptor positive allosteric modulator and nonbenzodiazepine/cyclopyrrolone [32] PF-572778 – undefined mechanism of action [33] Rufinamide (Banzel; CGP-33101; E-2080; Inovelon; RUF-331; SYN-111) – sodium channel blocker and other actions [34] Talaglumetad (LY-544344) – metabotropic glutamate mGlu2 and mGlu3 receptor agonist (eglumetad prodrug) [35] Tedatioxetine (Lu-AA24530) – serotonin–norepinephrine–dopamine reuptake inhibitor (SNDRI), serotonin 5-HT2A, 5-HT2C, and 5-HT3 receptor antagonist, and α1A-adrenergic receptor antagonist [36]
CEEs are naturally occurring estrane steroids. They are in conjugate form, as the sodium salts of the C17β sulfate esters. The estrogens in CEEs, in their unconjugated active forms, include bioidentical human estrogens like estradiol and estrone as well as equine-specific estrogens such as equilin and 17β-dihydroequilin. The equine estrogens differ from human estrogens in that they have additional double bonds in the B ring of the steroid nucleus. CEEs contain both 17β-estrogens like estradiol and 17β-dihydroequilin and the C17α epimers like 17α-estradiol and 17α-dihydroequilin.
== Origin and etymology == Kefir has been found in graves in the Bronze Age Xiaohe Cemetery, dating back 3,600 years. The word kefir is of North Caucasian origin, where related words are attested in several languages: Mingrelian ქიფური (kipuri), Karachay-Balkar гыпы (gıpı) and Ossetian къӕпы (k'æpy). One theory is that the word comes from Old Turkic köpür '(milk) froth'. It was loaned into Russian where it is attested since 1870s, and from there it was loaned into English, there attested in 1880s. It has become an internationalism, as it is found in many European languages. Kefir is a very popular drink in the North Caucasus, it is a part of traditional Circassian cuisine to this day. Traditional kefir was made in goatskin bags that were hung near a doorway; the bags would be knocked by anyone passing through to keep the milk and kefir grains well mixed. In Karachay-Balkar, gıpı has a connection with gıpıt (wineskin). It was under the name wineskin that Karachay kefir was distributed in the second half of the 19th century and at the beginning of the 20th century. Kefir spread from the former Soviet Union to the rest of Europe, Canada, Japan, and the United States by the early 21st century.
=== Pharmacokinetics === N-Desalkylflurazepam has an elimination half-life of 47–150 hours (up to 200 hours in some healthy volunteers), with an average of ~71 hours. Peak blood concentrations of N-Desalkylflurazepam is reached at 10.2 h following a single 15 mg dose of Flurazepam, typically around ~10-20.4 ng/mL. Its plasma levels are unreliable amongst patients, and are largely influenced by liver disease, liver enzyme inducers and inhibitors, as well as old age (in men).
Sources: en.wikipedia.org
Yes, the terms are generally interchangeable. Lyophilization is more common in pharmaceutical and laboratory contexts, while freeze-drying appears widely in food science and general writing. Both describe removal of solvent by sublimation under vacuum after freezing.
Reduced pressure keeps the process below the triple point of water, so ice can sublimate directly to vapor. It also lowers the temperature needed for drying, which helps preserve heat-sensitive materials. Without vacuum, melting or boiling could occur instead of controlled sublimation.
The rate depends on heat transfer to the product and mass transfer of vapor through the dried layer. A cold condenser, adequate vacuum, and suitable shelf temperature all influence speed. Formulation properties such as solid content and collapse temperature also set practical limits.
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.