The short version of primary drying fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-07-29 and is reviewed periodically as new material appears.
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.
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.
Analytical methods for lyophilized materials include X-ray diffraction for crystallinity, differential scanning calorimetry for thermal transitions, and scanning electron microscopy for pore morphology. Moisture sorption analysis shows how the cake responds to humidity. These methods help distinguish amorphous from crystalline states and detect phase changes. Open questions remain about how pore structure changes during long-term storage and how best to predict collapse under varied conditions. Comparisons across studies are complicated by differences in formulation, cycle, and storage history.
Quality control for lyophilized products focuses on appearance, moisture level, reconstitution time, and structural integrity. A cake should be uniform, intact, and free of meltback or collapse. Moisture level is measured by Karl Fischer titration or thermogravimetric analysis. Reconstitution time reflects pore structure and formulation. Visual inspection and vial integrity checks detect cracks, stopper defects, or particulate matter. These checks are often performed on samples from each batch. They help confirm that the drying cycle performed as intended.
Storage stability depends on water content, oxygen exposure, and temperature. Lyophilized solids are hygroscopic and can absorb water if exposed to humid air. Vials are usually sealed under vacuum or inert gas with rubber stoppers and aluminum crimps. Storage temperatures range from room temperature to refrigerated or frozen conditions depending on the material. Stability studies track potency, moisture, and physical form over time. Accelerated conditions can reveal sensitivity but may not predict long-term behavior.
| 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. |
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.
Stability of a lyophilized solid depends on water content, temperature, and the physical state of the formulation. Amorphous products may slowly absorb moisture and drop below their glass transition temperature, causing collapse or crystallization. Some proteins and peptides can aggregate even in a dry state, especially when exposed to heat or moisture. Accelerated stability studies at elevated temperature and humidity help estimate shelf life, but real-time data remain the basis for expiration dating.
After drying, a lyophilized product is usually sealed under vacuum or an inert gas to limit moisture and oxygen exposure. The container closure system matters because stoppers and seals can allow moisture ingress over time. Storage conditions are selected from stability studies that track potency, cake appearance, and reconstitution behavior. Many freeze-dried materials are kept at controlled room temperature, while some require refrigeration or protection from light.
=== January === 1 January Researchers operating China's Experimental Advanced Superconducting Tokamak (EAST) report the first experimental verification of a theorised density-free plasma operating regime, achieving stable electron densities approximately 1.3–1.65 times the Greenwald limit. Researchers at the Korea Advanced Institute of Science and Technology report a photo-Hall (Hall effect)–based method for detecting semiconductor electronic trap states with approximately 1,000-fold greater sensitivity than existing techniques. 2 January – Researchers at the Vienna University of Technology and the Okinawa Institute of Science and Technology demonstrate self-sustained superradiant microwave emission, produced by interacting spins in diamond, offering potential applications in quantum communication and sensing. 5 January – NASA announces that it has awarded contracts to seven companies to study technologies for the Habitable Worlds Observatory, a next-generation telescope that could launch in the 2040s. 7 January – Astronomers using data from the Vera C. Rubin Observatory report that 2025 MN45 has the fastest spin of any known asteroid larger than 0.5 km (0.31 mi) in diameter, completing one rotation every 1.88 minutes. 13 January The European Copernicus Climate Change Service reports that 2025 was the world's third hottest year on record (2024 was the hottest year and 2023 the second hottest). In Antarctica, the average annual temperature was the warmest since measurements began and in the Arctic, it was the second highest.
== ADLM Members == ADLM's approximately 8,000 members come from all areas of lab medicine—clinical and research laboratories, diagnostic companies, government agencies, original equipment manufacturers, and more. Collectively they develop and run lab tests and lab instruments used throughout healthcare. They also manage labs, conduct research involving biomarkers, and promote accurate diagnostic testing. ADLM represents the diverse interests of a global lab community: its members come from 110 countries and hold the spectrum of lab-related professional degrees, certifications, and credentials.
=== Names === Etifoxine is the generic name of the drug and its INNTooltip International Nonproprietary Name, BANTooltip British Approved Name, and DCFTooltip Dénomination Commune Française. It is also known by the older and much-lesser-used synonym etafenoxine and by its developmental code name Hoe 36801. Etifoxine is marketed under the brand name Stresam. It has also been marketed under the brand name Strezam.
From 2014, biosimilars were manufactured by several companies and sold at a lower price than before patent expiry. In 2014, Indian drugmaker Cadila Healthcare declared the launch of the first adalimumab biosimilar at a fifth of its US price. The generic was launched under the brand name Exemptia. In 2016, Indian drugmaker Torrent Pharmaceuticals launched its biosimilar for adalimumab, called Adfrar. It is the second generic biosimilar of adalimumab. In September 2016, the FDA approved Amgen's biosimilar adalimumab-atto, sold under the brand name Amjevita. In August 2017, the FDA approved German pharmaceutical company Boehringer Ingelheim's biosimilar, Cyltezo. In 2017, the biosimilars Amgevita, Solymbic, Imraldi, and Cyltezo were approved for use in the European Union. In 2018, the biosimilars Halimatoz, Hefiya, Hyrimoz, and Hulio were approved for use in the European Union. From 2018, Adalimumab biosimilars became available in the European Union, allowing the National Health Service to make record-breaking cost-savings, as this is the single most expensive drug used in NHS hospitals, costing more than £400 million a year for about 46,000 patients. In October 2018, adalimumab-adaz (Hyrimoz) was approved for use in the United States. In April 2019, Idacio and Kromeya were approved for use in the European Union. In July 2019, adalimumab-bwwd (Hadlima), produced by Samsung Bioepsis, was approved for use in the US. In November 2019, adalimumab-afzb (Abrilada) was approved in the United States. It is the 25th biosimilar approved by the FDA.
The main application of ZDDPs are as anti-wear additives in lubricants including greases, hydraulic oils, and motor oils. ZDDPs also act as corrosion inhibitors and antioxidants. Concentrations in lubricants range from 600 ppm for modern, energy-conserving low-viscosity oils to 3000 ppm in some racing oils. It has been reported that zinc and phosphorus emissions may damage catalytic converters and standard formulations of lubricating oils for gasoline engines now have reduced amounts of the additive due to the API limiting the concentration of this additive in new API SM and SN oils; however, this affects only 20- and 30-grade "ILSAC" oils. Grades 40 and higher have no regulation regarding the concentration of ZDDP, except for diesel oils meeting the API CJ-4 specification which have had the level of zddp reduced slightly, although most diesel Heavy-Duty Engine oils still have a higher concentration of this additive. Crankcase oils with reduced ZDDP have been cited as causing damage to, or failure of, classic/collector car flat-tappet camshafts and lifters which undergo very high boundary layer pressures and/or shear forces at their contact faces, and in other regions such as main bearings, and piston rings and pins. Roller camshafts/followers are more commonly used to reduce camshaft lobe friction in modern engines.
Sources: en.wikipedia.org
United Nations Security Council Resolution 283 was passed in June 1970 calling for all UN member states to close, or refrain from establishing, diplomatic or consular offices in South West Africa. The resolution also recommended disinvestment, boycotts, and voluntary sanctions of that territory as long as it remained under South African rule. In light of these developments, the Security Council sought the advisory opinion of the ICJ on the "legal consequences for states of the continued presence of South Africa in Namibia". There was initial opposition to this course of action from SWAPO and the OAU, because their delegates feared another inconclusive ruling like the one in 1966 would strengthen South Africa's case for annexation. Nevertheless, the prevailing opinion at the Security Council was that since the composition of judges had been changed since 1966, a ruling in favour of the nationalist movement was more likely. At the UN's request, SWAPO was permitted to lobby informally at the court and was even offered an observer presence in the courtroom itself. On 21 June 1971, the ICJ reversed its earlier decision not to rule on the legality of South Africa's mandate, and expressed the opinion that any continued perpetuation of said mandate was illegal. Furthermore, the court found that Pretoria was under obligation to withdraw its administration immediately and that if it failed to do so, UN member states would be compelled to refrain from any political or business dealings which might imply recognition of the South African government's presence there.
Building trust and acceptance of a licensed vaccine among the public is a task of communication by governments and healthcare personnel to ensure a vaccination campaign proceeds smoothly, saves lives, and enables economic recovery. When a vaccine is licensed, it will initially be in limited supply due to variable manufacturing, distribution, and logistical factors, requiring an allocation plan for the limited supply and which population segments should be prioritized to first receive the vaccine.
Barbara Seliger Larsen is a mass spectrometrist, with a career in instrumentations and applications of mass spectrometry in industry, and served on the board of the American Society for Mass Spectrometry for several terms.
A review of lichen taxonomic literature from 2018 to 2020 found that of over 700 new species published, only 39% included any DNA sequences. The most commonly used gene was the ITS (present in roughly 82% of those that had molecular data), while only about 10% of new species were supported by three or more genes. These figures show that while multilocus sequencing underpins higher-level systematics, species-level descriptions (alpha taxonomy) often remain constrained by practical limits on sequencing or by the sufficiency of morphological evidence. Sanger-era phylogenetics laid the groundwork for later genomic studies. By the late 2000s lichenologists had a working framework for most major lineages and clearer criteria for natural versus artificial groups. The framework relied on what now seem small datasets—only a few kilobases per species—yet these sequences resolved many relationships. Although some 2010-era authors questioned the value of small multigene matrices, Lücking (2020) contends that sound sampling and analysis can outweigh sheer data volume. By the early 2020s, many new species—even some higher taxa—are still described from a few gene regions plus morphology, a practise that remains practical where large-scale sequencing is not yet feasible. The Sanger era showed that modest molecular datasets could overturn classifications—splitting some genera, merging others—and it supplied a scaffold for later genome-scale studies.
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.
Karl Fischer titration is a common method, using coulometric or volumetric detection. Thermogravimetric analysis can also measure weight loss on heating. Results depend on sample handling because the dried solid can absorb moisture quickly.