The short version of Lyophilization fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-01-01. Anything still debated is marked as such rather than presented as settled.
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.
Stability programs monitor lyophilized products under defined temperature and humidity conditions over time. Real-time studies at recommended storage conditions are the reference, while accelerated studies provide early signals of degradation pathways. Because a dry cake can still undergo oxidation, hydrolysis, or aggregation, stability depends on residual moisture, excipients, and container headspace. Open questions include how best to predict long-term stability from short accelerated runs and how vial-to-vial variability affects shelf life. Current guidance treats these predictions as product-specific rather than universally generalizable.
Freeze-dried materials are hygroscopic to varying degrees and can take up moisture after drying. Storage therefore often uses sealed glass vials, rubber stoppers, and crimp seals to limit contact with ambient humidity. A desiccant may be included for moisture-sensitive products, although it is not universal. Controlled room temperature is sufficient for many lyophilizates, while others require refrigeration or freezing. Moisture ingress remains a primary cause of cake collapse, chemical degradation, and loss of reconstitution performance.
| Property | Value | Notes |
|---|---|---|
| Common synonym | Freeze-drying | Same dehydration operation |
| Typical vacuum | 10-100 Pa | Pressure during primary drying |
| Primary drying temperature | -40 to -10 °C | Below collapse temperature for many formulations |
| Cycle duration | 12-72 hours | Varies with load, container, and formulation |
| Key phase change | Sublimation | Solid ice to water vapor |
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.
Handling practices aim to prevent moisture ingress and mechanical damage. Vials should remain stoppered and crimped until use, and reconstitution should follow the labeled diluent and volume. Shipping may involve temperature-controlled containers and desiccants, but direct contact between desiccant and product is avoided. Regulatory guidance expects documented storage conditions, excursion assessments, and stability commitments. Open questions remain about how best to predict long-term stability from short accelerated studies for every formulation class.
After lyophilization, the product is usually a porous cake or powder with a large internal surface area. This structure can absorb moisture quickly if exposed to humid air, so vials are sealed under vacuum or an inert gas. Moisture uptake may lower the glass transition temperature of the dried matrix and accelerate chemical or physical degradation. Storage conditions therefore depend on the formulation, container, and intended shelf life. Some products remain stable at room temperature, while others require refrigeration or freezing.
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.
Quality control for freeze-dried forms includes visual inspection, water content measurement, and reconstitution time. A satisfactory cake is typically uniform, porous, and intact, although minor shrinkage or cracking may be acceptable if specifications allow. Karl Fischer titration, thermal gravimetric analysis, and near-infrared spectroscopy are used to measure water content. Reconstitution is assessed by adding a specified diluent and recording the time and ease of dissolution. Microbiological and particulate tests are added when the product is sterile or intended for injection.
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.
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==== COVID-19 ==== Dogs have been trained to sniff SARS CoV-2-related VOCs since the outbreak of COVID-19 pandemic. Their overall success rates of detection were similar to or higher than reverse transcription polymerase chain reaction (RT-PCR) and antigen testing procedures. Grandjean et al. trained the dogs to sit in front of samples from COVID-19 positive patients. The success rate of distinguishing the sweat odor of individuals with COVID-19 from individuals without COVID-19 was between 83% and 100%. In principle, the dogs could be used to screen individuals with various stages of COVID-19 infections (including asymptotic, presymptomatic individuals with mild to severe symptoms) in different settings such as schools, transportation centers like airports, hospitals, and public gatherings. An advantage of using trained dogs compared to primates or cats to detect COVID-19 is that dogs are animal species with a low risk of binding between ACE2 receptor and SARS CoV-2, making them less likely to be transmitters. To further minimize the risk of transmission to dogs, sniffing sweat (which has low transmission property) is deemed the ideal mechanism for dogs to detect COVID-19. Other advantages of using dogs for screening COVID-19 over the current RT-PCR method are lower cost, decreased intrusiveness to the subjects, and no delay in reporting the results.
=== Pregnancy === Lamividine/zidovudine is categorized pregnancy category C in the United States, meaning there are potential risks to the baby during pregnancy, but potential benefits may outweigh the risks. Data supports the safety of this combination during pregnancy and is often preferred over other fixed dose combinations during pregnancy.
23 July – The World Health Organization (WHO) declares the recent monkeypox outbreak a Public Health Emergency of International Concern, as the number of reported cases worldwide exceeds 17,000. In July, scientists reported that the window to be able to contain the outbreak is closing or has closed. On 5 July, a preprint indicates there can be asymptomatic infections. On 27 July, an analysis of studies by a journalist indicates that "about 10-to-15% of cases have been hospitalized, mostly for pain and bacterial infections that can occur as a result of monkeypox lesions". Studies published in August indicated hospitalizations of small cohorts of early patients were 8% and 13%. 25 July Researchers introduce the concept of necrobotics and demonstrate it by repurposing dead spiders as robotic grippers by activating their gripping arms via applying pressurized air. Researchers review the scientific literature on 100% renewable energy, addressing various issues, outlining open research questions, and concluding there to be growing consensus, research and empirical evidence concerning its feasibility worldwide. 26 July – Scientists analyse 2.8 million of the sequenced SARS-CoV-2 genomes and use the results to compile a 'mutations blacklist' of virus weak spots, and a 'whitelist' of mutations that would make it more transmissible. 27 July – Progress towards a pan coronavirus vaccine is announced, following tests on mice. Antibodies targeting the S2 subunit of SARS-CoV-2's spike protein are found to neutralise multiple coronavirus variants.
== Radiolabeled somatostatin receptor antagonists in Peptide Radionuclide Receptor Therapy (PRRT) == Somatostatin receptor antagonists are also being developed as therapeutic agents in peptide radionuclide receptor therapy (PRRT) due to the wider binding of antagonists compared to agonists. Research indicated the antagonist Lu-DOTA-JR11 showed a higher tumor uptake, more double-strand breaks within tumor cells, longer adherence time to tumors and improved tumor-to-kidney dose ratio. Moreover, another study finds out the radionuclide terbium-161, which can release short-ranged electrons, can combine with somatostatin receptor antagonists that localize at the cell membrane. acting as an alternative to the current clinically used lutetium-somatostatin receptor agonist, which are localized at the cytoplasm and nucleus. Moreover, Tb-antagonist in vitro shows 102-fold higher potency than Lu-antagonists in inhibiting tumor cell growth and survival prolongation in mice, due to its high linear energy transfer. This result is further repeated and confirmed in vivo, showing the high potential and strengths of radiolabeled somatostatin receptor antagonists to treat neuroendocrine neoplasms.
Sources: en.wikipedia.org
Manchester United defeat Manchester City 2–1 to win the 2024 FA Cup final. 26 May – British event rider Georgie Campbell dies after falling from her horse at the Bicton International Horse Trials in Devon. 27 May 2024 general election: Lucy Allan, outgoing Conservative MP for Telford is suspended from her party for backing Alan Adams, the Reform UK candidate to be her replacement. The RAF temporarily grounds its Spitfire planes following the fatal crash two days earlier. The FBI is reported to be investigating the sale of hundreds of British Museum artefacts to buyers in the United States. 28 May – Diane Abbott is readmitted as a Labour MP, following her suspension the previous year. 30 May 2024 general election: The Parliament elected in 2019 is dissolved. Buckingham Palace confirms that Charles III will attend the 2024 Trooping the Colour ceremony. 31 May – BBC News reports that the Battle of Britain Memorial Flight will not fly as part of D-Day anniversary events following the death of Squadron Leader Mark Long.
Transplantation experiments involving frog and newt epidermis indicated that the mesodermal signals are conserved between species but the epidermal response is species-specific meaning that the mesoderm instructs the epidermis of its position and the epidermis uses this information to make a specific structure.
=== Interdisciplinary === Interdisciplinary fields include agrochemistry, astrochemistry (and cosmochemistry), atmospheric chemistry, chemical engineering, chemical biology, chemo-informatics, environmental chemistry, geochemistry, green chemistry, immunochemistry, marine chemistry, materials science, mechanochemistry, medicinal chemistry, molecular biology, nanotechnology, oenology, pharmacology, phytochemistry, solid-state chemistry, surface science, thermochemistry, and many others.
From 2012 to 2022, the share of the market value of private sector firms in China's top listed companies increased from 10% to over 40%. He has overseen the relaxation of restrictions on foreign direct investment (FDI) and increased cross-border holdings of stocks and bonds. His administration made it easier for banks to issue mortgages, increased foreign participation in the bond market, and increased the national currency renminbi's global role, helping it to join IMF's basket of special drawing right. Xi launched the Shanghai Free-Trade Zone in 2013. In 2018, Xi announced the Shanghai Stock Exchange STAR Market, which opened in 2019. He also led the establishment of the Hainan Free Trade Port. In 2020, The Wall Street Journal reported that Xi ordered a halt to Ant Group's initial public offering (IPO), in reaction to its founder Jack Ma criticizing government regulation in finance. Under Xi, government guidance funds, public-private investment funds set up by or for government bodies, have raised more than $900 billion for early funding to companies that work in sectors the government deems as strategic. Xi's administration has overseen a decrease in offshore IPOs by Chinese companies, with most Chinese IPOs taking place either in Shanghai or Shenzhen as of 2022, and has increasingly directed funding to IPOs of companies that works in sectors it deems as strategic, including electric vehicles, biotechnology, renewable energy, artificial intelligence, semiconductors and other high-technology manufacturing.
Sources: en.wikipedia.org
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Lactiplantibacillus plantarum (formerly Lactobacillus arabinosus and Lactobacillus plantarum) is a widespread member of the genus Lactiplantibacillus and commonly found in many fermented food products as well as anaerobic plant matter. L. plantarum was first isolated from saliva. Based on its ability to temporarily persist in plants, the insect intestine and in the intestinal tract of vertebrate animals, it was designated as a nomadic organism. L. plantarum is Gram positive, bacilli shaped bacterium. L. plantarum cells are rods with rounded ends, straight, generally 0.9–1.2 μm wide and 3–8 μm long, occurring singly, in pairs or in short chains. L. plantarum has one of the largest genomes known among the lactic acid bacteria and is a very flexible and versatile species. It is estimated to grow between pH 3.4 and 8.8. Lactiplantibacillus plantarum can grow in the temperature range 12 °C to 40 °C. The viable counts of the "L. plantarum" stored at refrigerated condition (4 °C) remained high, while a considerable reduction in the counts was observed stored at room temperature (25 ± 1 °C).
Microfluidic liquid-liquid extraction has shown to be advantageous in numerous applications such as pharmacokinetic drug studies where only small cell numbers are needed, and in additional studies where smaller reagent volumes are required. Droplet-based microfluidics can also be used for chemical phase transfer reactions. An early example was the synthesis of azo dyes in nanoliter fluid segments using a double injector chip device.
=== Pathogenic fungi === The glyoxylate cycle may serve an entirely different purpose in some species of pathogenic fungi. The levels of the main enzymes of the glyoxylate cycle, ICL and MS, are greatly increased upon contact with a human host. Mutants of a particular species of fungi that lacked ICL were also significantly less virulent in studies with mice compared to the wild type. The exact link between these two observations is still being explored, but it can be concluded that the glyoxylate cycle is a significant factor in the pathogenesis of these microbes.
== Organization == The Hukbalahap was regarded by the PKP as its "citizen's army" against the Japanese. It was headed by the Central Luzon Bureau, with Vicente Lava as its secretary, and a secretariat, ostensibly a party apparatus meant to keep the Huks in line with PKP ideology. There were five committees which composed the Huk structure:
Sources: en.wikipedia.org
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.
Sublimation requires the solvent to remain solid so vapor leaves without passing through a liquid phase. If the product melts, the porous structure can collapse and drying becomes uneven. Maintaining frozen conditions preserves the intended physical form.
No, freeze-drying is a dehydration method, not a sterilization step. It can reduce water activity and limit microbial growth during storage, but it does not reliably kill microbes or remove endotoxins. Sterility must come from separate validated processes.
Many dried cakes are hygroscopic and can adsorb water during storage or handling. Absorbed moisture may lower the glass transition temperature and promote chemical reactions. Sealed packaging and controlled humidity reduce this risk.