Sublimation 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.
Last reviewed on 2026-06-09. Where a claim depends on a specific study, the study is described rather than over-claimed.
The physics of lyophilization couples heat transfer, mass transfer, and phase behavior. Sublimation requires a vapor pressure difference between the ice front and the chamber, and the dried layer adds resistance to vapor flow. Amorphous formulations are characterized by a glass transition temperature of the maximally freeze-concentrated solute, often denoted Tg'. Crystalline bulking agents can provide structure, while amorphous excipients stabilize labile components. Open questions remain about spatial heterogeneity, edge effects, and how laboratory cycles scale to production.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Physical state | Solid, porous cake or powder | Depends on formulation and container |
| Typical storage temperature | 2–25 °C, protected from moisture | Some materials require colder conditions |
| Solubility class | Usually readily soluble after reconstitution | Not an intrinsic chemical property |
| Common analytical method | Karl Fischer titration | Used for residual moisture |
| Common synonyms | Freeze-drying; lyophilisation | Lyophilisation is a spelling variant |
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, 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.
The physics of lyophilization depends on phase boundaries and heat and mass transfer. During primary drying, heat supplied to the product must equal the latent heat of sublimation, while water vapor moves through the drying cake to the condenser. If shelf temperature or pressure is set too high, the ice front can exceed the collapse temperature, causing meltback or pore collapse. If conditions are too cold, drying slows and costs rise. Formulation excipients, vial geometry, and freezing rate alter these limits.
=== Depression and anxiety === Tianeptine shows efficacy against serious depressive episodes (major depression), comparable to amitriptyline, imipramine and fluoxetine, but with significantly fewer side effects. It was shown to be more effective than maprotiline in a group of people with co-existing depression and anxiety. Tianeptine also displays significant anxiolytic properties and is useful in treating a spectrum of anxiety disorders including panic disorder, as evidenced by a study in which those administered 35% CO2 gas (carbogen) on paroxetine or tianeptine therapy showed equivalent panic-blocking effects. Like many antidepressants (including others Tricyclic antidepressant like Nortriptyline and Amitriptyline, Tetracyclic antidepressant, bupropion, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, Monoamine oxidase inhibitor among others) it may also have a beneficial effect on cognition in people with depression-induced cognitive dysfunction. , especially in elderly patients A 2005 study in Egypt showed tianeptine to be effective in men with depression and erectile dysfunction. Tianeptine has been found to be effective in depression, in people with Parkinson's disease, and with post-traumatic stress disorder for which it was as safe and effective as fluoxetine and moclobemide.
=== Influence of timing === As most nutrient supplements feed all living microorganism in the must (whether desirable or not), winemakers will often wait to add the nutrients until they are ready to inoculate the must with their desired S. cerevisiae strain. Producers who are using wild ferments may also wait until after sulfur dioxide additions have killed off unwanted microbes or feed early because they would like the potential complexity that other microbes could add to the wine. When added, the nitrogen is usually in the form of amino acids, combined with vitamins and minerals to help kick start the fermentation.
Note that the incompressible case correspond to the assumption that the pressure constrains the flow so that the volume of fluid elements is constant: isochoric flow resulting in a solenoidal velocity field with
Homology - the structure is similar between the two species because of shared ancestry and common genetics. Convergence - the structure is similar between the two species because of independent adaptation to common environmental pressures. Understanding which characteristics and structures belong to each type is an important part of understanding plant evolution. The evolutionary biologist relies on the plant morphologist to interpret structures, and in turn provides phylogenies of plant relationships that may lead to new morphological insights.
A Cochrane systematic review in 2011 showed that treatment with Sulphonylurea did not improve control of glucose levels more than insulin at 3 nor 12 months of treatment. The review found evidence that treatment with Sulphonylurea could lead to earlier insulin dependence, with 30% of cases requiring insulin at 2 years. When studies measured fasting C-peptide, no intervention influenced its concentration, but insulin maintained concentration better than Sulphonylurea. The authors also examined a study utilizing Glutamic Acid Decarboxylase formulated with aluminium hydroxide (GAD65), which showed improvements in C-peptide levels that were maintained for 5 years. Vitamin D with insulin also demonstrated steady fasting C-peptide levels in the vitamin group, with the same levels declining in the insulin-only group at a 12-month follow-up. One study examining the effects of insulin together with Chinese remedies on fasting C-peptide on a 3-month follow-up did not show a difference compared to insulin alone. However, the studies available to be included in this review presented considerable flaws in quality and design.
Sources: en.wikipedia.org
Faced with possibility of ongoing player boycotts – including a potential boycott of the following month's Brownlow Medal count, which was televised by Seven – the Seven Network issued a statement regretting any harm the broadcast may have caused to the AFL, the clubs and the players, and promised not to broadcast or reveal any of the details of the medical records in future. The AFLPA, which had previously demanded an apology from the network over the incident, said that it understood why Seven could never issue a full apology "for legal reasons" and that it would be taking the "statement of regret" as an apology instead. The player boycott has since been lifted. The woman who found the medical records and a male accomplice were charged with "theft-by-finding" and faced Heidelberg Magistrates' Court on 6 December 2007. They subsequently pleaded guilty and were sentenced to a 12-month good behaviour bond and ordered to pay the money they received from Channel 7 into a court fund.
In addition, it continues to be common practice for men to shave their heads prior to embarking on a pilgrimage. The unibrow is considered a sign of beauty and attractiveness for women in Oman and for both genders in Tajikistan, often emphasized with kohl. In Middle Eastern societies, regular trimming or removal of female and male underarm hair and pubic hair has been considered proper personal hygiene, necessitated by local customs, for many centuries. Young girls and unmarried women, however, are expected to retain their body hair until shortly before marriage, when the whole body is depilated from the neck down. In China, body hair has long been regarded as normal, and even today women are confronted with far less social pressure to remove body hair. The same attitude exists in other countries in Asia. While hair removal has become routine for many of the continent's younger women, trimming or removing pubic hair, for instance, is not as common or popular as in the Western world, where both women and men may trim or remove all their pubic hair for aesthetic or sexual reasons. This custom can be motivated by reasons of potentially increased personal cleanliness or hygiene, heightened sensitivity during sexual activity, or the desire to take on a more exposed appearance or visual appeal, or to boost self-esteem when affected by excessive hair.
There is a clear relationship between known hydrocarbon discoveries at great depth in the Gulf slope and chemosynthetic communities, hydrocarbon seepage, and authigenic minerals including carbonates at the seafloor. While the hydrocarbon reservoirs are broad areas several kilometers beneath the Gulf, chemosynthetic communities occur in isolated areas with thin veneers of sediment only a few meters thick. The northern Gulf of Mexico slope includes a stratigraphic section more than 10 km (6.2 mi) thick and has been profoundly influenced by salt movement. Mesozoic source rocks from Upper Jurassic to Upper Cretaceous generate oil in most of the Gulf slope fields. Migration conduits supply fresh hydrocarbon materials through a vertical scale of 6–8 km (3.7–5.0 mi) toward the surface. The surface expressions of hydrocarbon migration are called seeps. Geological evidence demonstrates that hydrocarbon and brine seepage persists in spatially discrete areas for thousands of years. The time scale for oil and gas migration from source systems is on the scale of millions of years (Sassen, 1997). Seepage from hydrocarbon sources through faults towards the surface tends to be diffused through the overlying sediment, carbonate outcroppings, and hydrate deposits, so the corresponding hydrocarbon seep communities tend to be larger (a few hundred meters wide) than chemosynthetic communities found around the hydrothermal vents of the Eastern Pacific (MacDonald, 1992). There are large differences in the concentrations of hydrocarbons at seep sites.
== In popular culture == In the 1998 film The Big Lebowski, after one of the protagonists dies, their ashes are transported to the Pacific Ocean in a Folgers coffee can because the cheapest urn is deemed too expensive. The film has become a cult classic, and at least one person has dressed up as a can of Folgers during a fan event. In the 1991 Seinfeld episode "The Library", Jerry is challenged by Lt. Bookman (played by Philip Baker Hall) on why there is no instant coffee available for guests to his apartment: "You buy a jar of Folger's Crystals, you put it in the cupboard, you forget about it. Then later on when you need it, it's there. It lasts forever. It's freeze-dried. Freeze-dried crystals." The November 16, 1991 episode of Saturday Night Live had a sketch that parodied the 'high end restaurant' commercials from the 1970s and 1980s, showing a customer (Chris Farley) violently losing his temper upon being informed that he was given another company's coffee blend instead of the restaurant's usual blend.
Sources: en.wikipedia.org
=== Early days of Pentagram === Though Pentagram struggled with lineup changes and financial issues, the band became a key influence in the development of doom metal, with Liebling's distinct vocals and songwriting playing a major role in their cult following. Their early recordings, particularly Relentless (1985) and Day of Reckoning (1987), laid the groundwork for future doom metal acts. Despite their potential, Liebling's struggles with substance abuse, internal conflicts, and frequent lineup changes prevented Pentagram from achieving stability and mainstream success. By the mid-1970s, the band had caught the attention of influential managers and producers. One such figure was Gordon Fletcher, a columnist for Rolling Stone and Creem, who connected them with Sandy Pearlman and Murray Krugman, producers and managers of Blue Öyster Cult. Pentagram had an opportunity to record a full album, but the deal collapsed when Liebling, dissatisfied with the production of one of his tracks, had a heated argument with Krugman. As a result, Krugman walked out, canceling their contract. Gene Simmons and Paul Stanley of Kiss were invited to a Pentagram rehearsal, with hopes of impressing them and securing their mentorship. However, guitarist Vince McAllister and bassist Greg Mayne, who at the time were janitors, arrived late, still in their dirty uniforms from work. The Kiss members mocked their appearance rather than taking the band seriously. Despite this, Paul Stanley offered to purchase some of their songs, but Liebling refused, wanting to keep control of his material.
Immune-mediated causes could include transient factors as in Mycoplasma pneumoniae infection (cold agglutinin disease) or permanent factors as in autoimmune diseases like autoimmune hemolytic anemia (itself more common in diseases such as systemic lupus erythematosus, rheumatoid arthritis, Hodgkin's lymphoma, and chronic lymphocytic leukemia). Spur cell hemolytic anemia Any of the causes of hypersplenism (increased activity of the spleen), such as portal hypertension. Acquired hemolytic anemia is also encountered in burns and as a result of certain infections (e.g. malaria). Lead poisoning or poisoning by arsine or stibine causes non-immune hemolytic anemia. Runners can develop hemolytic anemia due to "footstrike hemolysis", the destruction of red blood cells in feet at foot impact. Low-grade hemolytic anemia occurs in 70% of prosthetic heart valve recipients, and severe hemolytic anemia occurs in 3%.
John Thomas Chain Jr. (December 11, 1934 – July 7, 2021) was a U.S. Air Force general. He was also a director of R. J. Reynolds Tobacco Company, ConAgra Foods, Inc., and Kemper Insurance Co., as well as holding other corporate offices.
Sources: en.wikipedia.org
Freezing only converts liquid to solid. Lyophilization adds vacuum and controlled warming so frozen solvent sublimes, leaving a dry porous solid. The two steps are related but not interchangeable.
Reduced pressure keeps the solvent below its triple point, allowing ice to become vapor without melting. Vacuum also helps remove water vapor from the product chamber. The exact pressure is chosen with the formulation and equipment.
Residual moisture is water that remains in the dried solid after secondary drying. It is often measured by Karl Fischer titration, near-infrared spectroscopy, or thermogravimetry. Acceptable levels depend on the material and its stability profile.
The main change is sublimation, in which ice becomes water vapor without melting into liquid water. This occurs when the chamber pressure is held below the vapor pressure of ice while mild heat is supplied. The result is a dry, porous solid that retains much of its original shape.