This is a working overview of sublimation, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-05-22. Anything still debated is marked as such rather than presented as settled.
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.
Equipment for lyophilization includes a vacuum chamber, temperature-controlled shelves, a condenser, and a vacuum pump. A refrigeration system cools the shelves and condenser below the product's freezing point. Process monitoring often uses Pirani and capacitance manometers, thermocouples, and resistance sensors. Cycle development balances product quality with time and energy use. Some products are annealed during freezing to improve crystallization of bulking agents. Open questions remain about scaling cycles between laboratory, pilot, and production freeze-dryers.
Lyophilization, also called freeze-drying, removes water from a frozen material by sublimation under reduced pressure. The process begins with freezing, which converts free water into ice and may also produce a glassy phase. Primary drying then lowers chamber pressure so ice sublimes directly to vapor without passing through a liquid stage. Secondary drying raises the temperature modestly to remove bound water. The result is a porous, dry solid that usually reconstitutes quickly. Each stage influences pore structure, residual moisture, and stability.
| Property | Value | Notes |
|---|---|---|
| Process name | Lyophilization or freeze-drying | Both terms appear in technical standards and literature. |
| Phase transition | Sublimation | Solid ice becomes vapor without a liquid step. |
| Typical chamber pressure | 0.05-0.5 mbar | Range depends on product temperature and equipment. |
| Typical product temperature | -40 °C to -10 °C | Measured during primary drying; formulation sets limits. |
| Water content after drying | 0.5-3% w/w | Target varies by material and stability needs. |
The process relies on the phase diagram of water, where the triple point marks the conditions at which ice, liquid water, and vapor coexist. By maintaining pressure below this point, typically around 0.01 to 0.1 millibar, sublimation becomes the dominant mechanism. Formulations often include excipients such as sugars or polymers that act as lyoprotectants and bulking agents. These additives help preserve the structure of the active ingredient and prevent collapse during drying. The choice of excipient and freezing rate influences the final cake morphology and stability.
Industries use lyophilization for pharmaceuticals, biological products, and food preservation. In the pharmaceutical sector, it extends the shelf life of injectable drugs, vaccines, and proteins that are unstable in aqueous solution. Food manufacturers apply freeze-drying to coffee, fruits, and ready meals to retain flavor and texture. The process is energy-intensive and requires specialized equipment, which limits its use to high-value products. Ongoing research examines how formulation and process parameters affect the quality of the final dried product.
Lyophilization, also known as freeze-drying, is a process that removes water from a material by freezing it and then reducing pressure to allow ice to sublimate directly into vapor. The method begins with a freezing step that solidifies the water content. Next, primary drying lowers the pressure below the triple point of water, enabling sublimation without passing through a liquid phase. A final secondary drying step removes bound water through desorption. This sequence produces a dry, porous cake that can be reconstituted later.
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.
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.
Lyophilization is a dehydration process that removes water from a frozen material by sublimation under low pressure. The material is first frozen to convert liquid water into ice. Next, the pressure is reduced below the triple point of water so that ice changes directly into vapor without passing through a liquid phase. This step is called primary drying. The result is a porous solid or cake that retains the original shape of the frozen solution.
After primary drying, secondary drying removes water that remains bound to the material. This stage raises the shelf temperature while maintaining low pressure, which encourages desorption of unfrozen water. Residual moisture can be reduced to a low percentage, improving stability for many products. The process parameters, including freezing rate, shelf temperature, and chamber pressure, influence the final pore structure and reconstitution behavior. Control of these variables helps prevent collapse or meltback during drying.
A formulation often contains excipients that protect the active ingredient during freezing and drying. Bulking agents provide structure, while lyoprotectants stabilize sensitive molecules. The freezing step can produce ice crystals whose size and distribution affect the drying rate, and cycle design includes freezing, annealing, and drying phases. If the product temperature rises above a critical value, the cake may collapse or lose its porous structure. Successful lyophilization therefore depends on the interaction between formulation, equipment, and cycle design.
== Diuretics and masking agents == Diuretics, sometimes known as ‘water pills,’ are drugs that alter the body's fluid and salt balance, increasing urine production. They are used for the swelling and bloating of premenstrual syndrome, for treating high blood pressure, and in older people for heart failure caused by weakening of the heart's pumping mechanism. Diuretics can be used to pass a drug test because they increase the amount of urine produced by the body, thereby it dilutes any drugs in the urine which makes it harder to identify them. Examples of diuretics and masking agents are bumetanide, chlorothiazide, furosemide, hydrochlorothiazide, probenecid, spironolactone (canrenone), triameterene, and trichlormethiazide. Finasteride is not banned.
The Partido Comunista de España (Reconstituido) (English: "Communist Party of Spain (Reconstituted)", PCE(r)) is a Spanish clandestine Marxist-Leninist party that broke away from the Communist Party of Spain (PCE). The general secretary of the PCE(r) is Manuel Pérez Martínez ('Comrade Arenas') who was in prison from 2000 to March 2025 for terrorist activities.
Though GSK-3 has been shown to promote apoptosis in some cases, it has also been reported to be a key factor in tumorigenesis in some cancers. Supporting this claim, GSK-3 inhibitors have been shown to induce apoptosis in glioma and pancreatic cancer cells. GSK-3 also seems to be responsible for NFκB aberrant activity in pediatric acute lymphoblastic leukemia and pancreatic cancer cells. In renal cancer cells, GSK-3 inhibitors induce cell cycle arrest, differentiation of the malignant cells, and autophagy. In contrast to the above neoplasms, high expression of inactive pGSK3β-S9 is found in skin, oral, and lung cancers, suggesting tumor suppressive effects of the enzyme in these cancers. In melanoma, the microRNA miR-769 inhibits GSK-3 activity during the tumor development process, also indicating tumor suppressive effects of GSK3. GSK-3 inhibitors have also shown promise in the treatment of T2DM. Though GSK-3 activity under diabetic conditions can differ radically across different tissue types, studies have shown that introducing competitive inhibitors of GSK-3 can increase glucose tolerance in diabetic mice. GSK-3 inhibitors may also have therapeutic effects on hemorrhagic transformation after acute ischemic stroke. GSK-3 can negatively regulate the insulin signaling pathway by inhibiting IRS1 via phosphorylation of serine-332, rendering the insulin receptor incapable of activating IRS1 and further initiating the canonical PI3K/Akt pathway. The role that inhibition of GSK-3 might play across its other signaling roles is not yet entirely understood.
Britain gathered allies to form the Third Coalition against The French Empire after Napoleon was self-proclaimed as emperor. In response, Napoleon seriously considered an invasion of Great Britain, massing 180,000 troops at Boulogne. Before he could invade, he needed to achieve naval superiority—or at least to pull the British fleet away from the English Channel. A complex plan to distract the British by threatening their possessions in the West Indies failed when a Franco-Spanish fleet under Admiral Villeneuve turned back after an indecisive action off Cape Finisterre on 22 July 1805. The Royal Navy blockaded Villeneuve in Cádiz until he left for Naples on 19 October; the British squadron caught and overwhelmingly defeated a Franco-Spanish fleet in the Battle of Trafalgar on 21 October (the British commander, Lord Nelson, died in the battle). Napoleon never again had the opportunity to challenge the British at sea, nor to threaten an invasion. He again turned his attention to the enemies on the Continent.
== Function == The protein encoded by this gene is an adaptor protein which contains five LIM domains, or double zinc fingers. The protein is likely involved in integrin signaling through its LIM domain-mediated interaction with integrin-linked kinase, found in focal adhesion plaques. It is also thought to act as a bridge linking integrin-linked kinase to NCK adaptor protein 2, which is involved in growth factor receptor kinase signaling pathways. Its localization to the periphery of spreading cells also suggests that this protein may play a role in integrin-mediated cell adhesion or spreading.
Sources: en.wikipedia.org
=== Worm infections === For river blindness (onchocerciasis) and lymphatic filariasis, ivermectin is typically given as part of mass drug administration campaigns that distribute the drug to all members of a community affected by the disease. Adult worms survive in the skin and eventually recover to produce larval worms again; to keep the worms at bay, ivermectin is given at least once per year for the 10–15-year lifespan of the adult worms. The World Health Organization (WHO) considers ivermectin the drug of choice for strongyloidiasis. Ivermectin is also the primary treatment for Mansonella ozzardi and cutaneous larva migrans. The US Centers for Disease Control and Prevention (CDC) recommends ivermectin, albendazole, or mebendazole as treatments for ascariasis. Ivermectin is sometimes added to albendazole or mebendazole for whipworm treatment, and is considered a second-line treatment for gnathostomiasis. When co-administered, ivermectin and albendazole act in synergy. Ivermectin targets the parasite's nervous and muscular systems, causing paralysis, while albendazole disrupts the parasite's metabolism and energy production. This dual approach immobilizes and kills the parasite and improves the treatment's effectiveness. In January 2025, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive scientific opinion for ivermectin/albendazole for the treatment of infections caused by several types of worm parasites including lymphatic filariasis, a neglected tropical disease.
=== Mitral stenosis === Mitral stenosis is caused almost exclusively by rheumatic heart disease, and has a prevalence of about 0.1% in the United States. Mitral stenosis is the most common valvular heart disease in pregnancy.
== Modern colloquial usage == The term "culottes" in more recent French describes women's underpants, an article of clothing that has little or no relation to the historical culottes, but now also refers to apparent skirts that are actually split with two legs. The term sans-culottes has been used colloquially to mean not wearing underpants.
=== Shadowhunters === Cordelia Carstairs — a Shadowhunter arriving in London trying to make powerful friends in order to save her family from disgrace. She is brave, loyal, selfless, and determined, and wields the mythical sword known as Cortana. She has been in love with James since the two were children. Unlike her older brother, Alastair, she is well-liked by the other characters. She has long dark red hair, black eyes, and light brown skin. James Herondale — Cordelia's childhood friend and crush, who is very popular and handsome. He is intelligent and introverted, and struggles with his demonic heritage on his mother's side. He has the ability to travel into the shadow realm, though he has difficulty controlling this ability. While he falls in love with Cordelia, he has been in love with Grace for several years due to the fact that she is manipulating his emotions with the help of a seemingly harmless bracelet he has worn for a while. He has pale skin, black hair, and gold eyes. Lucie Herondale — Cordelia's soon-to-be parabatai and James's younger sister. Lucie is a lively young girl who is very talkative, protective, and friendly. She is an aspiring writer and writes an ongoing novel known as "The Beautiful Cordelia", which she sends to Cordelia to read every month. She has the ability to see all kinds of ghosts and command them to do her bidding. She has pale skin, brown hair, and blue eyes. Matthew Fairchild — James's parabatai, who is cheerful, flirtatious, and sometimes considered scandalous by many of the London Shadowhunters.
Sources: en.wikipedia.org
Conventional drying uses heat to evaporate liquid water, often at temperatures that can degrade sensitive materials. Lyophilization freezes the material first and then removes water by sublimation under vacuum. This avoids prolonged exposure to liquid water and high heat.
Lowering pressure reduces the boiling point of water and allows ice to sublimate at temperatures below freezing. Vacuum also limits convective heat transfer, so heat is usually supplied by shelves or radiation. The pressure must stay below the vapor pressure of ice at the product temperature.
The cycle typically includes freezing, primary drying, and secondary drying. Freezing solidifies water and sets the pore structure; primary drying removes bulk ice; secondary drying removes bound water. Some cycles add annealing or pre-freezing steps.
Simple drying usually removes water by evaporation from a liquid or solid, often with heat. Lyophilization first freezes the material and then removes ice by sublimation under vacuum. This avoids prolonged exposure to liquid water and high temperatures.