The short version of cake fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-09-30. Anything still debated is marked as such rather than presented as settled.
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.
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.
The process usually has three stages: freezing, primary drying, and secondary drying. Freezing sets the ice crystal structure and can determine pore size in the final cake. Primary drying removes free ice by sublimation at low pressure and low shelf temperature. Secondary drying removes bound water by raising the shelf temperature, although some water may remain as part of the solid. Cycle parameters depend on formulation, fill volume, vial type, and equipment performance.
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 |
|---|---|---|
| Common name | Freeze-drying | Lyophilization is the technical synonym. |
| Typical chamber pressure | 0.01–0.1 mbar | Below the triple point of water. |
| Primary drying temperature | −40 to −10 °C | Depends on formulation and equipment. |
| Residual moisture | 1–5% | Target for many pharmaceutical products. |
| Typical equipment | Vacuum freeze-dryer | Includes drying chamber and condenser. |
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.
The process generally proceeds in three stages: freezing, primary drying, and secondary drying. During freezing, controlled cooling converts water into ice and may also crystallize or vitrify solutes. In primary drying, the pressure is lowered below the triple point, and heat is supplied so ice sublimes directly to vapor. Secondary drying removes water that remains bound to the solid matrix, yielding a low final water content. Product temperature must stay below the collapse or glass transition temperature to maintain structure. Cycle design therefore balances shelf temperature, chamber pressure, and time.
Freeze-drying is used for materials whose activity or structure depends on low temperature and low water content. Examples include certain biologics, diagnostic reagents, starter cultures, coffee, and porous inorganic precursors. The dried product forms a cake whose porosity aids rapid wetting and dissolution. Main drawbacks are high energy use, long cycle times, and sensitivity to formulation and equipment variation. Questions remain about how freezing rates and ice morphology affect batch uniformity, especially when moving from laboratory to production scale.
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.
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.
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.
21 May – IBM announces that it will begin development of a 100,000-qubit quantum computer, the world's largest and most powerful, to be completed by 2033. 22 May – A study quantifies "the human cost of global warming", showing current policies "leading to around 2.7 °C global warming could by 2080–2100 leave one-third (22–39%)" of people outside their climate niche (see also 4 May 2020) – humans' long-time range of mean annual temperatures to which their physiology may have largely adapted to. It indicates meeting the 1.5 °C goal would decrease the population exposed to unprecedented heat ~5-fold and ties itself to earlier research by initially noting that quantifying the social cost of carbon in monetary terms, as related or economics studies tend to do, may be inadequate. 23 May Using the Hubble Space Telescope and Gaia spacecraft, an analysis of proper motions of the closest known globular cluster, Messier 4, reveals an excess mass of roughly 800 solar masses in the center. This appears to not be extended, and could thus be the best kinematic evidence for an intermediate-mass black hole (even if an unusually compact cluster of compact objects, white dwarfs, neutron stars or stellar-mass black holes cannot be completely discounted). A study identifies plastic chopping boards as a substantial source of ingested microplastics. Researchers show plastic recycling facilities are a major source of microplastic water pollution (1 May).
Ghana, officially the Republic of Ghana, is a country in West Africa. It is situated with the Gulf of Guinea and the Atlantic Ocean to the south, and shares borders with Ivory Coast to the west, Burkina Faso to the north, and Togo to the east. Ghana covers an area of 239,567 km2 (92,497 sq mi), spanning various ecologies, from coastal savannas to tropical rainforests. With over 35 million inhabitants, Ghana is the thirteenth-most populous country in Africa, and the second-most populous country in West Africa. The capital and most populous city is Accra. The earliest kingdoms to emerge in Ghana were Bonoman in the south and the Kingdom of Dagbon in the north, with Bonoman existing in the area during the 11th century. The Asante Empire and other Akan kingdoms in the south emerged over the centuries. Beginning in the 15th century, the Portuguese Empire, followed by other European powers, contested the area for trading rights, until the British ultimately established control of the coast by the 19th century. Following more than a century of colonial resistance, the later borders of the country took shape, encompassing four separate British colonial territories: Gold Coast, Ashanti, the Northern Territories, and British Togoland. These were unified as an independent dominion within the Commonwealth of Nations. On 6 March 1957, Ghana became the first colony in Sub-Saharan Africa to achieve sovereignty. Under President Kwame Nkrumah, it became influential in decolonisation efforts and the Pan-African movement.
=== Muscle repair === Stem cells have successfully been used to ameliorate healing in the heart after myocardial infarction in dogs. Adipose and bone marrow derived stem cells were removed and induced to a cardiac cell fate before being injected into the heart. The heart was found to have improved contractility and a reduction in the damaged area four weeks after the stem cells were applied. In 2007, a trial was underway for a patch made of a porous substance onto which the stem cells are "seeded" in order to induce tissue regeneration in heart defects. Tissue was regenerated and the patch was well incorporated into the heart tissue. This is thought to be due, in part, to improved angiogenesis and reduction of inflammation. Although cardiomyocytes were produced from the mesenchymal stem cells, they did not appear to be contractile. Other treatments that induced a cardiac fate in the cells before transplanting had greater success at creating contractile heart tissue. 2018 research, such as the European nTRACK research project, aims to demonstrate that multimodal nanoparticles can structurally and functionally track stem cell in muscle regeneration therapy. The idea is to label stem cells with gold nano-particles that are fully characterised for uptake, functionality, and safety. The labelled stem cells will be injected into an injured muscle and tracked using imaging systems. However, the system still needs to be demonstrated at lab scale.
=== Prevention === Prevention relies on a farm to plate approach involving the whole supply chain anchored in risk analysis and good hygiene practices. Internationally, the Codex Alimentarius General Principles of Food Hygiene provide the foundation for national food safety systems and industry controls. These guidelines are then implemented through various prerequisite programs and HACCP (Hazard Analysis and Critical Control Point) which identify, monitor, and control hazards at specific steps in production. For consumers and food service businesses, evidence-based guidance involves four key steps: Clean, Separate, Cook, Chill. These techniques reduce cross-contamination and ensure lethal heat treatment and rapid refrigeration. Since supply chains are complex, it is critical to prioritize monitoring high-risk foods, such as minimally processed fresh produce, and modifying controls such as, agricultural water safety, manure management, worker hygiene, and post-harvest sanitation. Overall, strengthening surveillance and rapid information-sharing through a One Health lens by linking human, animal, and environmental data, improves outbreak detection and targeted interventions. This is a priority of the WHO Global Strategy for Food Safety 2022–2030.
Sources: en.wikipedia.org
=== Use in musical instruments === Birch wood is sometimes used as a tonewood for semiacoustic and acoustic guitar bodies, and occasionally for solid-body guitar bodies. It is also a common material used in mallets for keyboard percussion. Drum manufacturers, such as Gretsch and Yamaha, have been known to use birch wood in the construction of drum shells, owing to its strength and colour which takes stain in an appealing way, and which can also amber over very well, while also giving the drums an appealing tone which changes depending on the type of birch used.
=== New generation fuel === The aim of Guy Reinaud's project is to reply to the needs, in renewable domestic energy, of a population of 2 billion individuals living in the tropical regions of Africa, Latin America and Asia, and at the same time fighting against deforestation and climatic changes. The proposed solution is biomass charcoal as a source of renewable energy - patented and developed by Pro-Natura International. Biomass charcoal produces domestic energy from non-upgraded biomass, other than wood, in particular agricultural residues non-consumed by animals. By reducing the dependence on wood, biomass charcoal protects forests and as a consequence fights against desertification. Moreover, the energy produced by biomass charcoal is equal to that of wood charcoal for a sales price per kilo 50% cheaper.
==== Transportation of RNP and viral proteins to cellular membrane ==== After translation, SeV nucleocapsids (RNP complex) assemble, and move using microtubules network through intracellular vesicular trafficking pathway. In preparation for the budding process, three viral lipophilic proteins HN, F and M migrate through the secretory pathway to a host cell membrane. It is assumed that the interaction of these three proteins with each other is needed for their migration to cellular budding sites. The binding of lipophilic protein complex to the host membrane facilitates the interaction of this three protein complex with the SeV nucleocapsid. It has been shown that for efficient virion production SeV induces the β-cytoplasmic actin remodeling in its host cell.
Common side effects of hydrocodone are nausea, vomiting, constipation, drowsiness, dizziness, lightheadedness, anxiety, abnormally happy or sad mood, dry throat, difficulty urinating, rash, itching, and contraction of the pupils. Serious side effects include slowed or irregular breathing and chest tightness. Several cases of progressive bilateral hearing loss unresponsive to steroid therapy have been described as an infrequent adverse reaction to hydrocodone/paracetamol misuse. This adverse effect has been considered by some to be due to the ototoxicity of hydrocodone. Other researchers have suggested that paracetamol is the primary agent responsible for the ototoxicity. The U.S. Food and Drug Administration (FDA) assigns the drug to pregnancy category C, meaning that no adequate and well-controlled studies in humans have been conducted. A newborn of a mother taking opioid medications regularly prior to the birth will be physically dependent. The baby may also exhibit respiratory depression if the opioid dose was high. An epidemiological study indicated that opioid treatment during early pregnancy results in increased risk of various birth defects. Symptoms of hydrocodone overdose include narrowed or widened pupils; slow, shallow, or stopped breathing; slowed or stopped heartbeat; cold, clammy, or blue skin; excessive sleepiness; loss of consciousness; seizures; or death. Hydrocodone can be habit forming, causing physical and psychological dependence. Its abuse liability is similar to morphine and less than oxycodone.
== American Chemical Society == The Frank H. Field and Joe L. Franklin Award for Outstanding Achievement in Mass Spectrometry is the major mass spectrometry award offered by the American Chemical Society.
Sources: en.wikipedia.org
=== Pharmacokinetics === Migalastat is almost completely absorbed from the gut; taking the drug together with food decreases its absorption by about 40%. Total bioavailability is about 75% when taken without food. The substance is not bound to blood plasma proteins. Only a small fraction of a migalastat dose is metabolized, mainly to three dehydrogenated O-glucuronides (4% of the dose) and a number of unspecified metabolites (10%). The drug is mainly eliminated via the urine (77%) and to a smaller extent via the faeces (20%). Practically all of the metabolites are excreted in the urine. Elimination half-life is three to five hours after a single dose.
In those with a body mass index (BMI) under 35, intra-abdominal body fat is related to negative health outcomes independent of total body fat. Intra-abdominal or visceral fat has a particularly strong correlation with cardiovascular disease. BMI and waist measurements are well recognized ways to characterize obesity. However, waist measurements are not as accurate as BMI measurements. Waist measurement (e.g., for BFP standard) is more prone to errors than measuring height and weight (e.g., for BMI standard). BMI will illustrate the best estimate of one's total body fatness, while waist measurement gives an estimate of visceral fat and risk of obesity-related disease. It is recommended to use both methods of measurements.
The retention factor of the compound of interest should be around 0.2 - 0.3 in order to minimize the time and the amount of eluent to run the chromatography. The other compounds should have retention factors quite different from that of the compount of interest. To pick a good eluent, one run multiple small scale pretests, often using thin layer chromatography (TLC) with the same stationary phase, using solvents of different polarity, until a suitable solvent system is found. Common mobile phase solvents, in order of increasing polarity, include hexane, dichloromethane, ethyl acetate, acetone, and methanol. A common solvent system is hexane:ethyl acetate mixture. The proportions are adjusted so that the target compound has a retention factor of 0.2 - 0.3. Contrary to common misconception, methanol alone can be used as an eluent for highly polar compounds, and does not dissolve silica gel. The eluent flow rate can be optimized. A higher flow rate eluent decreases the time required to run a column and thereby decreases diffusion, improving the resolving power. However, if the flow rate is too high, the analyte would fail to equilibrate between the stationary phase and mobile phase (see Van Deemter's equation). To increase the flow rate of a gravity-flow column chromatography, one can increase the height of the fresh eluent column above the top of the stationary phase, or decrease the tap controls. It can also be increased by using a pump or by using compressed gas (e.g. air, nitrogen, or argon) to push the solvent through the column (flash column chromatography).
Cocaine is delivered daily in containers to the Port of Antwerp, before it is distributed throughout Europe by Dutch and Belgian-Moroccan drug traffickers. The Port of Antwerp, which is considered to be the largest port for cocaine import in Europe, is dominated and controlled by 5 Moroccan drug clans who export these large quantities of cocaine to the European mainland. Gangs preferred to use the Port of Antwerp as a trafficking destination for drugs due to the lawlessness within the port. Additionally, with an area of 12,068 hectares (~24,000 football fields), the scale of the port is what makes it attractive to criminals. Within a single cargo ship, it is possible to place up to 15,000 containers. Customs officers use scanners, that are only able to scan a single container in 5 minutes, which makes full control over the entire cargo pretty much impossible. This makes drug trafficking easier for gangs operating in the port. What also attracted the gangs, is the fact that the Port of Antwerp is considered to be an "open port". This is not the case for the Port of Rotterdam, which is closed off daily and under high surveillance. Bart De Wever, at the time mayor of Antwerp (since 2025 Prime Minister of Belgium), declared in 2017 that dozens of surveillance cameras are destroyed daily by young people between the age of 13 and 15 from neighbourhoods in Antwerp. They receive in exchange a sum of up to €5,000 from traffickers to prevent the police from investigating the drug trade that takes place in these neighbourhoods.
Sources: en.wikipedia.org
Conventional drying uses heat to evaporate water from a material, while lyophilization freezes the material and removes water by sublimation under vacuum. This avoids the liquid phase and reduces thermal damage to sensitive substances. The result is a porous cake that reconstitutes quickly.
A vacuum lowers the pressure below the triple point of water, allowing ice to sublimate directly into vapor without melting. It also removes water vapor from the product chamber and speeds up the drying process. Without vacuum, the ice would melt rather than sublimate.
Not all substances are suitable for lyophilization. Materials must form a stable frozen matrix and tolerate freezing and low pressure. Some small molecules, oils, or volatile compounds may not form a proper cake or may be lost during processing.
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.