This is a working overview of Primary drying, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-04-07 and is reviewed periodically as new material appears.
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.
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.
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.
| 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. |
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.
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.
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.
Functional KORs are present on nerve terminals of both oxytocin and vasopressin neurons in the rat neurohypophysis, where agonists inhibit potassium-evoked hormone release. Both dynorphin1-8 and (1–17) suppress stimulated oxytocin release from isolated neurosecretory endings, with effects on the initial and secondary peaks of hormone secretion, while exerting no influence on vasopressin release under similar conditions. These interactions extend to plasma hormone levels, where KOR agonists decrease circulating oxytocin concentrations, while antagonists increase oxytocin release, suggesting that KOR signaling mediates negative regulation of oxytocin secretion during stress or physiological challenges.
Many countries have stockpiled first generation smallpox vaccines. In a 2006 predictive analysis of casualties if there were a mass vaccination of the populations of Germany and the Netherlands, it was estimated that a total of 9.8 people in the Netherlands and 46.2 people in Germany would die from uncontrolled vaccinia infection after being vaccinated with the New York City Board of Health strain. More deaths were predicted for vaccines based other strains: Lister (55.1 Netherlands, 268.5 Germany) and Bern (303.5 Netherlands, 1,381 Germany).
In addition to plasmids, the player can collect and buy tonics that provide passive bonuses, such as increasing Jack's strength, using EVE more efficiently, or making Jack more resistant to damage. The player can only have a limited number of plasmids and tonics active at any time, and can swap between the various plasmids and tonics at certain stations located throughout Rapture. Plasmids and tonics are purchased using ADAM, which is gathered by choosing to harvest or save Little Sisters. If one chooses to harvest Little Sisters, they will get the maximum amount of Adam, but they won't survive the process. However If the player saves the Little Sisters, they will receive less Adam, but Tenenbaum will make it worth your while. Accessing the Little Sisters requires defeating the armored Big Daddies that protect them; if the player avoids attacking the Big Daddies or the Little Sisters, they remain neutral to the player. The game provides several options to face challenges. In addition to direct combat, the player can use plasmids to lure enemies into traps or to turn enemies against each other, or employ stealth tactics to avoid detection by hostiles including the security systems and turrets. The player can hack into any of Rapture's automated systems; the hacking process is done via a mini-game where the player must connect two points on opposite sides of a grid with a limited set of piping within a fixed amount of time, with failure to complete in time costing health and potentially sounding alarms.
It is not a set of techniques so much as a willingness to help a client explore spirituality and/or transcendent states of consciousness. Transpersonal psychology is concerned with helping clients achieve their highest potential. Multiculturalism – Although the theoretical foundations of psychology are rooted in European culture, there is a growing recognition that there exist profound differences between various ethnic and social groups and that systems of psychotherapy need to take those differences into greater consideration. Further, the generations following immigrant migration will have some combination of two or more cultures—with aspects coming from the parents and from the surrounding society—and this process of acculturation can play a strong role in therapy (and might itself be the presenting problem). Culture influences ideas about change, help-seeking, locus of control, authority, and the importance of the individual versus the group, all of which can potentially clash with certain givens in mainstream psychotherapeutic theory and practice. As such, there is a growing movement to integrate knowledge of various cultural groups in order to inform therapeutic practice in a more culturally sensitive and effective way. Feminism – Feminist therapy is an orientation arising from the disparity between the origin of most psychological theories (which have male authors) and the majority of people seeking counseling being female. It focuses on societal, cultural, and political causes and solutions to issues faced in the counseling process.
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== Energy consumption == Due to the low temperature, ULT freezers consume high amounts of electric energy and hence are expensive to operate. In 2010, Stanford University had more than 2,000 ULT freezers, which used an estimated 40 billion BTUs of energy and cost the university $5.6 million annually. Newer ULT freezers consume less energy. Nonetheless, a comprehensive report published in 2015 by the Center for Energy Efficient Laboratories (funded by Pacific Gas & Electric, Southern California Edison, and San Diego Gas & Electric utility companies as part of their Emerging Technologies program) found that laboratories in California consumed an estimated 800 GWh/year, with ULT freezers being the greatest contributor to that total. At least as early as 2018, some scientists suggested that laboratories set freezers to –70 °C instead of –80 °C to conserve energy and decrease wear on the freezer's compressor. Depending on the volume of the freezer, the opening frequency of the users as well as the number of samples, the energy consumption starts from ca. 11 kWh/day and higher. The US government calculates 20 kWh/day. A study performed at the University of Edinburgh showed that the New Brunswick U570 HEF model consumed slightly under 10 kWh/day. Without any data, the University of Michigan claimed that "older model" ULT devices could consume "up to 30 kWh/day". A sales pitch written in 2023 quoted "16-22 KWh of electricity per day". To reduce the energy consumption, the insulation should be as efficient as possible.
As there are more customers using cards and mobile apps, Starbucks has decided to reduce the amount of stores that use cash. However, for the elderlies and foreigners, they do accept cash in rare occasions. This is not only to apply the newest technology to the stores, but to apply the change of lifestyle, making it convenient for both the customers and partners. Starbucks Korea said October 16, 2024. it has partnered with the country's leading retail lender KB Kookmin Bank to introduce account-based settlement services for its customers in the first quarter of next year. Starbucks Korea announced on the 28th Oct. that it will increase the prices of 11 tall (355ml) iced beverages on its menu from the 1st of next month. The price increase will include two blended drinks, six frappuccinos, one physio, and two refreshers, each of which will increase by 200 won.
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FAT10 (or Ubiquitin D) is a tandem UBL protein that is also degraded by the proteasome in a ubiquitin independent manner. Recent biochemical and structural studies show that FAT10 is degraded upon binding of NUB1 that unfolds the first UBL of FAT10 enabling engagement by the 26S proteasome. The NUB1-FAT10 complex also exposes a UBL on NUB1 that binds Rpn1, positioning FAT10 above the central channel of the proteasome. Midnolin was identified as a protein that targeted transcription factors to the proteasome for ubiquitin independent degradation. Recent structural studies show that the UBL of midnolin binds Rpn11, a helix binds Rpn1, and the CATCH domain binds the transcription factor, providing a model for how ubiquitin independent degradation occurs. Pathogens also have learned to take advantage of ubiquitin-independent degradation. For plants, a parasitic Phytoplasma, expresses SAP05, a protein that binds transcription factors and target them for degradation by the 26S proteasome by binding the VWA domain of Rpn10. Interestingly, SAP05 does not bind the insect vector Rpn10. Crystal structures show how SAP05 binds both these TFs and Rpn10 indicating that SAP05 places the TFs near the entry of the AAA motor allowing for ubiquitin independent degradation.
=== Schizophrenia === Early evidence suggests sarcosine is an effective and well-tolerated adjuvant to many antipsychotics except clozapine for the treatment of schizophrenia, showing significant reductions in both positive and negative symptoms.
Sources: en.wikipedia.org
Under the name "Project TAME", he produced the XA cigarette using palladium. However, in 1978, his project was terminated. Since 1950, the average nicotine and tar content of cigarettes has steadily fallen. Research has shown that the fall in overall nicotine content has led to smokers inhaling larger volumes of smoke per puff.
== Major metabolic pathways converging on the glyoxalase cycle == Although the glyoxalase pathway is the main metabolic system that reduces methylglyoxal levels in the cell, other enzymes have also been found to convert methylglyoxal into non-AGE producing species. Specifically, 99% of MG is processed by glyoxalase metabolism, while less than 1% is metabolized into hydroxyacetone by aldo-keto reductases (AKRs) or into pyruvate by aldehyde dehydrogenases (ALDH). Other reactions have been found to produce MG that also feeds into the glyoxalase pathway. These reactions include catabolism of threonine and acetone, peroxidation of lipids, autoxidation of glucose, and degradation of glycated proteins.
=== Counterfeits === In October 2023, there were reports of counterfeit Ozempic pens being sold in Europe. The pens possibly contained insulin, and led to several people being hospitalised with hypoglycemia and seizures. In December 2023, the US FDA issued a warning about counterfeit Ozempic.
Condensation reactions likely played major roles in the synthesis of the first biotic molecules including early peptides and nucleic acids. In fact, condensation reactions would be required at multiple steps in RNA oligomerization: the condensation of nucleobases and sugars, nucleoside phosphorylation, and nucleotide polymerization.
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.
Primary drying removes ice by sublimation under vacuum. Secondary drying removes water that is bound to the material, often by warming the product after most ice has left. Both stages occur below temperatures that would cause unwanted melting.