Everything below concerns Sublimation. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-06-24. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Freezing determines ice crystal structure and pore size, which affect drying speed and product uniformity. Rapid freezing creates small crystals, while slow freezing creates larger crystals and often faster sublimation. During primary drying, chamber pressure is held below the vapor pressure of ice, and shelf temperature supplies heat for sublimation. The ice front recedes, leaving a porous matrix. Thermal limits such as collapse and eutectic temperatures set safe boundaries for formulation. These limits vary with solute composition and concentration.
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.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Freeze-drying; lyophilisation; cryodesiccation | Regional spelling and historical terms. |
| Primary drying pressure | 0.05-0.5 mbar (5-50 Pa) | Kept below the triple point of water; product-specific. |
| Shelf temperature range | -40 to +40 °C | Freezing, primary, and secondary stages use different set points. |
| Cycle duration | 12-72 hours | Depends on fill volume, formulation, and equipment. |
| Condenser temperature | -50 to -80 °C | Must remain below the product's ice temperature. |
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.
The physics of freeze-drying couples heat transfer, mass transfer, and phase change. Heat supplied through the shelf must reach the sublimation front without melting the ice or degrading the product. Water vapor then travels through the already dried layer and leaves the chamber, where low pressure and cold traps keep it from returning. The dried layer acts as a resistance to vapor flow, so drying rate changes as the front recedes. Open questions remain about how pore structure and formulation heterogeneity affect drying uniformity at larger scales.
Lyophilization removes water from a frozen material by sublimation under reduced pressure. The process begins with freezing, which converts liquid water into ice and concentrates dissolved solids. Primary drying then lowers chamber pressure so ice changes directly into vapor without passing through a liquid phase. Secondary drying raises the shelf temperature to remove bound water that remains after ice sublimation. The result is a dry, porous structure that can be reconstituted later.
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.
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.
Conversely, in rats, blood cholesterol is inversely correlated with cholesterol consumption: the more cholesterol a rat eats the lower the blood cholesterol. During the first seven hours after ingestion of cholesterol, as absorbed fats are being distributed around the body within extracellular water by the various lipoproteins (which transport all fats in the water outside cells), the concentrations increase. Plants make cholesterol in very small amounts. In larger quantities they produce phytosterols, chemically similar substances that compete with cholesterol for reabsorption in the intestinal tract, thus potentially reducing cholesterol reabsorption. When intestinal lining cells absorb phytosterols, in place of cholesterol, they usually excrete the phytosterol molecules back into the GI tract, an important protective mechanism. The intake of naturally occurring phytosterols, which encompass plant sterols and stanols, ranges between ≈200–300 mg/day depending on eating habits. Specially designed vegetarian experimental diets have been produced yielding upwards of 700 mg/day.
=== Crime === Moore has blamed his predecessor, Governor Larry Hogan, for increased violent crime in Maryland, citing his lack of collaboration between his administration and local leaders and legislators. During his 2022 gubernatorial campaign, he called on Hogan to target state resources toward preventing gun violence in Baltimore and campaigned on addressing crime in the city through better cooperation between the city and state, and to leverage these relationships on the federal level to bring more resources into the city. In January 2023, Moore told CBS News that he supported a bill that would prohibit charging juveniles with felony murder. In January 2023, following the release of videos capturing the arrest and police assault of Tyre Nichols, Moore condemned the brutality of the police and thanked the United States Department of Justice for opening an investigation into Nichols's death. He later said in an interview that Nichols's death only highlighted the need to tackle injustice head-on. In February 2023, Moore pledged $11 million in funding for the Maryland Coordination and Analysis Center, an agency that serves as a data-sharing platform for law enforcement officials across the state. He also said that his administration would not use a quota system for traffic stops and arrests after a Baltimore Banner investigation found that Maryland State Police supervisors previously demanded troopers hit targets for traffic stops and arrests.
=== Flagship facility === UPMC Presbyterian Shadyside is UPMC's primary flagship medical entity and represents the core of UPMC's academic, teaching, trauma, specialty and research-related facilities, serving as the system's primary academic hub and Pennsylvania's largest inpatient acute care hospital. UPMC Presbyterian Shadyside includes UPMC Presbyterian hospital and the physically conjoined UPMC Eye & Ear and UPMC Montefiore hospitals as well as the UPMC Western Psychiatric Hospital that also serves as the University of Pittsburgh's Thomas Detre Hall. These facilities are all located on the western side of the University of Pittsburgh's main campus in the Oakland neighborhood of Pittsburgh. The hospitals are also physically connected to the University of Pittsburgh School of Medicine's Scaife Hall, the University of Pittsburgh School of Nursing's Victoria Hall, Falk Clinic, three of the university's biomedical science towers, and the university's Lothrop Hall dormitory, all of which are surrounded by a variety of other academic facilities. UPMC Presbyterian Shadyside also encompasses the UPMC Shadyside hospital campus which includes the University of Pittsburgh Cancer Institute in the UPMC Hillman Cancer Center which are located near the university's Centre Plaza Apartments student housing. The UPMC Shadyside facilities are located in the adjacent neighborhood of Shadyside approximately 1.5 miles (2.4 km) from the Oakland-based hospitals and are connected by regular shuttle service.
== Pharmacology == U-47700 is an agonist of the μ-opioid receptor (Ki 11.1 ± 0.4 nM) and possesses significantly lower affinity for the κ-opioid receptor (Ki = 287 ± 24 nM) and δ-opioid receptor (Ki = 1220 ± 82 nM). U-47700 is approximately 10-fold more potent than morphine in rats, although the binding of U-47700 is 2–4 times weaker than morphine at all three opioid receptors. The metabolism of U-47700 in humans involves mono- and didesmethylation followed by hydroxylation. The desmethyl metabolites of U-47700 have negligible affinity for the opioid receptors and are not thought to contribute to the activity of U-47700.
Sources: en.wikipedia.org
== Production and processing == Producing a biomaterial from raw silk generally proceeds through three stages: the fibroin is purified, dissolved into a workable solution, then shaped and stabilised into a final form. Cocoons are boiled in a mild alkaline solution, usually sodium carbonate, which removes the sericin. The degummed fibres are then dissolved, most often in concentrated lithium bromide, a salt concentrated enough to disrupt the hydrogen bonds holding the beta-sheet domains together. Dialysis against water removes the salt and leaves an aqueous fibroin solution, the common precursor for nearly everything that follows. A single solution yields a striking variety of forms. Dried as a thin layer on a surface, it produces films and coatings used in optics, in sensors and to modify the surfaces of implants. When the protein assembles into a soft, water-swollen network—a transition driven by changes in pH or temperature, by sonication or by an applied electric field—the result is a hydrogel. Freeze-drying, or casting the protein around salt crystals or gas bubbles, produces porous sponges and scaffolds whose interconnected pores allow cells to grow in three dimensions. Drawing the solution through a high electric field spins it into fine fibres, a technique known as electrospinning, which yields non-woven mats resembling the natural network surrounding cells. The same solution can also be formed into microspheres and nanoparticles for carrying and releasing drugs.
The situation during Tehuantepecers and Santa Ana wind events are more complicated, as they occur when air rushing southward due to cold air damming east of the Sierra Madre Oriental and Sierra Nevada respectively, is accelerated when it moves through gaps in the terrain. The Santa Ana is further complicated by down-sloped air, or foehn winds, drying out and warming up in the lee of the Sierra Nevada and coastal ranges, leading to a dangerous wildfire situation.
On average, the temperature of the ocean surface in the tropical East Pacific is roughly 8–10 °C (14–18 °F) cooler than in the tropical West Pacific. The sea surface temperature (SST) of the West Pacific northeast of Australia averages around 28–30 °C (82–86 °F). SSTs in the East Pacific off the western coast of South America are closer to 20 °C (68 °F). Strong trade winds near the equator drive water away from the East Pacific and into the West Pacific. This water is slowly warmed by the Sun as it moves west along the equator, the wind stress acting on the ocean surface being balanced by a sea surface slope. One result of this is that sea levels near Indonesia are typically around 0.5 m (1.5 ft) higher than that near Peru. The warm surface waters collect in the western Pacific, with the result that the thermocline, the transitional zone between the warmer waters near the ocean surface and the cooler waters of the deep ocean, lies much deeper in the western Pacific, where it has an average depth of around 140 m (450 ft) compared to around 30 m (90 ft) in the East Pacific. At depth, the sloping surface thermocline helps reduce the east–west pressure difference due to the sea level slope, but below the thermocline, the pressure difference is still enough to drive the eastward flowing cold equatorial undercurrent. The cooler deep ocean water replaces the outgoing surface waters in the East Pacific, rising to the ocean surface in a process called upwelling.
Protein Data Bank (PDB) is a database of three dimensional structures of biological macromolecules, such as proteins and nucleic acids. The data are typically obtained by X-ray crystallography or nuclear magnetic resonance spectroscopy (NMR spectroscopy), and submitted manually by structural biologists worldwide through PDB member organizations – PDBe, RCSB, PDBj and BMRB. The database can be accessed through the webpages of its members, including PDBe (housed at the EMBL-EBI). As a member of the Worldwide Protein Data Bank (wwPDB) consortium, PDBe aids in the joint mission of archiving and maintenance of macromolecular structure data.
Norethisterone acetate (NETA), also known as norethindrone acetate and sold under the brand name Primolut-Nor among others, is a progestin medication which is used in birth control pills, menopausal hormone therapy, and for the treatment of gynecological disorders. The medication is available in low-dose and high-dose formulations and is used alone or in combination with an estrogen. It is ingested orally. Side effects of NETA include menstrual irregularities, headaches, nausea, breast tenderness, mood changes, acne, increased hair growth, and others. NETA is a progestin, or a synthetic progestogen, and hence is an agonist of the progesterone receptor, the biological target of progestogens like progesterone. It has weak androgenic and estrogenic activity and no other important hormonal activity. The medication is a prodrug of norethisterone in the body. NETA was patented in 1957 and was introduced for medical use in 1964. It is sometimes referred to as a "first-generation" progestin. NETA is marketed widely throughout the world. It is available as a generic medication.
Sources: en.wikipedia.org
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.
Reduced pressure lowers the boiling point of water and allows ice to sublime at temperatures below freezing. It also helps remove water vapor from the product toward the condenser. The exact pressure is chosen to stay below the triple point of water.
No. Materials with low solids content or high volatile solvents may form weak or collapsed cakes. Some proteins and cells require stabilizers to survive freezing and drying stresses. Feasibility depends on formulation and process design.
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.