This is a working overview of Sublimation, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-11-02. Anything still debated is marked as such rather than presented as settled.
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.
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.
Quality assessment of a lyophilized product includes cake appearance, residual moisture, reconstitution time, and container closure integrity. A uniform, porous cake suggests that freezing and drying stayed within the formulation's design space. Cracks, shrinkage, meltback, or a glassy film can indicate thermal abuse or a formulation problem. Analysts also test for subvisible particles and sterility when the product requires those specifications. Visual inspection alone cannot confirm biological activity or chemical stability, so it is combined with analytical methods.
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 synonyms | Freeze-drying, lyophilisation | Lyophilisation is the British spelling; the process is not simple evaporation. |
| Primary drying pressure | 0.05–0.3 mbar | Pressure must remain below the vapor pressure of ice at the product temperature. |
| Sublimation temperature | Below 0 °C | Ice changes directly to vapor while the product remains frozen. |
| Typical shelf temperature | −40 to −10 °C | Exact setting depends on formulation critical temperature and equipment. |
| Cycle duration | 12–72 hours | Time varies with fill volume, formulation, and dryer performance. |
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.
Formulation composition influences whether freeze-drying produces an intact cake or a collapsed mass. Excipients such as sugars and polymers can raise the collapse temperature and provide bulk during drying. The critical temperature for primary drying is often the collapse temperature or the glass transition temperature of the maximally concentrated phase. If the product temperature exceeds this threshold, the frozen matrix may soften and lose structure. Established practice therefore links shelf temperature and chamber pressure to the formulation's thermal properties.
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.
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.
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.
Reconstitution involves adding a suitable diluent, often sterile water or a buffer, to the dried cake. Gentle swirling or inversion helps dissolve the material without creating excessive foam. The time required for complete dissolution can range from seconds to several minutes and depends on the cake structure and the diluent. Improper reconstitution, such as vigorous shaking or using the wrong diluent, can cause protein aggregation or loss of activity. After reconstitution, the product may have a limited shelf life and should be used according to its labeling.
Lyophilized products are typically hygroscopic and require protection from moisture during storage. Manufacturers seal them in glass vials, often under vacuum or an inert gas such as nitrogen. The container closure system, including the stopper and crimp seal, must prevent water vapor ingress. Storage temperature varies from controlled room temperature to refrigerated or frozen conditions, depending on the formulation. Humidity-controlled environments are essential because even brief exposure to ambient air can degrade the product.
Stability of a lyophilized product depends on its glass transition temperature, the temperature at which the amorphous cake transitions from a glassy to a rubbery state. Storage below this temperature minimizes molecular mobility and slows chemical degradation. If the storage temperature exceeds the glass transition temperature, the cake may collapse, shrink, or become sticky. Accelerated stability studies at elevated temperatures and humidity help predict shelf life, but they do not always reflect real-time behavior. Residual moisture content also plays a critical role in long-term stability.
=== Food constituents === Resistant starch from high-amylose corn, amylomaize, has been shown to reduce insulin resistance in healthy individuals, in individuals with insulin resistance, and in individuals with type 2 diabetes. Some types of polyunsaturated fatty acids (omega-3) may moderate the progression of insulin resistance into type 2 diabetes, however, omega-3 fatty acids appear to have limited ability to reverse insulin resistance, and they cease to be efficacious once type 2 diabetes is established.
This is interpreted by some researchers to mean that although the incorporation of lactobacillic acid into the cell membrane has no significant influence on the physical properties of the membrane, it does change its chemical properties, which is an advantage for the organism. One example of a beneficial effect of lactobacillic acid is provided by Oenococcus oeni. The lactic acid bacterium is used in wine production to convert malic acid into lactic acid during malolactic fermentation into lactic acid, which in turn is converted into ethanol by baker's yeast. In this way, the acidity of the wine is reduced. In the process, Oenococcus oeni is exposed to relatively high concentrations of ethanol produced by yeasts during alcoholic fermentation. Studies of the cell membrane of the bacterium have shown that the biosynthesis rate of phospholidides is increased with increasing ethanol concentration in the surrounding culture medium. In addition, more lactobacillic acid is formed in the membrane lipids, while the content of cis vaccenic acid decreases. This is interpreted as a protective mechanism against the toxic effects of ethanol. The formation of lactobacillic acid helps the bacterium to adapt to unfavorable environmental conditions. A similar protective effect was discovered in L. delbrueckii subsp. bulgaricus. It shows improved survivability against freeze-drying when more lactobacillic acid is present in the cell membrane.
A freeze alarm (also called a low-temperature alarm or freeze monitor) is a device that tracks ambient temperature and issues an alert when the temperature falls below a user-defined threshold. Its chief purpose is to warn property owners early enough to prevent freeze-related damage such as burst water pipes, failed heating systems, or losses to temperature-sensitive goods. Repairing a single burst pipe in a residence can cost well over US$10,000 on average, making proactive warnings financially attractive.
== Post-natal functions of neohormones == After birth, neohormones play a major role in development of mammary glands and their function. Alongside, neohormones have also been measured to be a significant component of breast milk. The so-called lactocrine hypothesis dictates that breast milk does not simply fulfil nutritional requirements but also plays an important role in signaling and development in the neonate. Neohormones are theorised to have specific effects on target organs in the neonate, but more research is needed in this area, and effects have been observed to different extents in different species.
Sources: en.wikipedia.org
== Society and culture == Vaginal mesh kits were introduced to the U.S. market in 2004 through the U.S. Food and Drug Administration (FDA) pathway that did not require companies to demonstrate both safety and efficacy of the product if they were able to demonstrate that their product was similar to previous products already in the market. However, there was concern over reports of increased rates of postoperative complications over the next several years. That, in addition to the lack of available data that transvaginal mesh products were superior to other forms of surgical intervention and the expedited process which the vaginal mesh kits were introduced to the market, the FDA released a Safety Communication in 2011 that described serious complications associated with transvaginal mesh as "not rare". In 2019, the FDA ordered manufacturers to halt sales of transvaginal mesh intended for repair of pelvic organ prolapse. This does not include surgical mesh used during sacrocolpopexy, sacrohysteropexy, or transurethral sling procedures. Since 2008, a number of class action lawsuits have been filed and settled against several manufacturers of transvaginal mesh after people reported complications following surgery.
== See also == Ghulam Ishaq Khan Institute of Engineering Sciences and Technology University of Swabi Women University Mardan Shaheed Benazir Bhutto Women University, Peshawar Government Post Graduate College (Swabi)
=== Anatomical defects === Anatomical or functional defects of the seminal tract may cause flow obstruction of seminal pathways. This can be observed in people with genetic mutations (specifically the CFTR gene) or ejaculatory duct obstruction(s) such as prostate or seminal vesicle cysts. Mutations of the CFTR gene on chromosome 7 can cause an overproduction of thick, sticky mucus in organs with mucous glands, contribute to infertility through clogging the spermatic duct with mucus, and cause congenital bilateral absence of the vas deferens. Examples of anatomical defects include:
In addition to the classical nuclear AR, bicalutamide has been assessed at the membrane androgen receptors (mARs) and found to act as a potent antagonist of ZIP9 (IC50 = 66.3 nM), whereas it does not appear to interact with GPRC6A. The affinity of bicalutamide for the AR is relatively low as it is approximately 30 to 100 times lower than that of DHT, which is 2.5- to 10-fold as potent as an AR agonist as testosterone in bioassays and is the main endogenous ligand of the receptor in the prostate gland. However, typical clinical dosages of bicalutamide result in circulating levels of the drug that are thousands of times higher than those of testosterone and DHT, allowing it to powerfully prevent them from binding to and activating the receptor. This is especially true in the case of surgical or medical castration, in which testosterone levels in the circulation are approximately 95% reduced and DHT levels in the prostate gland are about 50 to 60% reduced. In women, levels of testosterone are substantially lower (20- to 40-fold) than in men, so much smaller doses of bicalutamide (e.g., 25 mg/day in the hirsutism studies) are necessary. Blockade of the AR by bicalutamide in the pituitary gland and hypothalamus results in prevention of the negative feedback of androgens on the hypothalamic–pituitary–gonadal axis (HPG axis) in males and consequent disinhibition of pituitary luteinizing hormone (LH) secretion. This, in turn, results in an increase in circulating LH levels and activation of the gonadal production of testosterone and by extension production of estradiol.
Rosenberg states, "These mechanisms reveal a picture of highly regulated mutagenesis, up-regulated temporally by stress responses and activated when cells/organisms are maladapted to their environments—when stressed—potentially accelerating adaptation." Since they are self-induced mutagenic mechanisms that increase the adaptation rate of organisms, they have some times been named as adaptive mutagenesis mechanisms, and include the SOS response in bacteria, ectopic intrachromosomal recombination and other chromosomal events such as duplications.
Sources: en.wikipedia.org
=== Post-2003 === Production ended on 2 October 2003 and the whole Familia line were replaced by the Mazda3 in the same month. The eighth generation Familia continued to be produced by Ford Lio Ho in Taiwan as the "Mazda Isamu Genki" until 2008 (sold as hatch and saloon and with little or no styling differences to the original 1998 production model). It was also badged as the "Ford Activa", which, unlike the Ford Laser, had no styling changes from the 323, except for the badges. In Southeast Asia, a version of the last Laser continued to be assembled in Indonesia, Malaysia, and the Philippines as the Ford Lynx. This generation remained in production in some South American countries (Ecuador, Colombia, and Venezuela), badged as the Mazda Allegro. Each Allegro keeps in the styling of the last generation 323/Protegé/Astina/Familia. In Colombia, production of the Mazda 323 continued until 2003, built by its local subsidiary, the Compañía Colombiana Automotriz. Chinese company FAW Haima Automobile Co., Ltd. produces a restyled version of the Familia/323 called Haima Family from 2003 to 2010. It is equipped with a 1.6 L petrol engine mated with a five-speed manual or a four-speed automatic gearbox. Another version called the Haima Happin went on sale from 2008 to 2012 model years with a facelift for 2011 and 2012 models. The Happin was equipped with a 1.3 L, 1.5 L, and 1.6 L engine options and a five-speed manual gearbox.
Andrej Janež is a Slovenian diabetologist and diabetes researcher. Janež is the Head of Department of Endocrinology, Diabetes and Metabolic Disease at University Medical Centre Ljubljana, Assistant Professor for Internal Medicine at the Medical University Ljubljana, Chairman of the Advances in Diabetes and Insulin Therapy conference, member of the advisory board for peroral antidiabetic therapy in Servier Pharma, member for Slovenia in the Diabetes Education Study Group at European Association for the Study of Diabetes, and member of the European advisory board for continuous glucose monitoring system in development for Lifescan. Janež authored numerous articles on diabetology and indexed by Science Citation Index, co-edited a clinical manual on continuous subcutaneous insulin infusion therapy, or insulin pump treatment. The latter is also the best known area of Janež's scientific work, as he introduced insulin pump treatment to India, Turkey, China, Slovenia, and several other countries, where he also led the effort of educating teams of diabetologists required for a continuous application of the technique.
== Life == John H. Reynolds was born (1923-04-03)April 3, 1923 in Cambridge, Massachusetts. He studied first at Harvard University and, after serving in the Navy during World War II, at the University of Chicago. There, he was influenced by his Ph.D. thesis advisor Mark Inghram and by two other famous physicists, Harold Urey and Enrico Fermi. He specialized in mass spectrometry and utilized this method to determine isotope ratios needed for the radiometric dating of geologically and cosmologically relevant samples. In 1950 he was appointed as professor to the University of California, Berkeley where he continued his research on isotope ratios in meteorites, leading to the discovery in 1960 that the Richardton meteorite and other meteorites had an excess of xenon-129, thought to be a result of the beta decay of iodine-129 in the early Solar System. He was helped by a new all-glass spectrometer that he had designed, which allowed gas samples to be run through it multiple times, helping to increase the odds of detection and alleviate the low sensitivity problems plaguing earlier attempts by other researchers on other meteorites. Unlike many scientific discoveries, the significance of the discovery was well and widely understood at the time. His improvement of potassium-argon dating was also adopted by several institutions. Reynolds was a Guggenheim Fellow for the academic years 1956–1957 and 1986–1987. He was elected to the National Academy of Sciences in 1968. He died of pneumonia on November 4, 2000, in Berkeley, California.
==== Killing of Israeli civilians ==== The elimination of the State of Israel has been a primary goal for Hezbollah. Hezbollah has been accused of "only [regarding] the Jews living in Israel as Zionists, who should be killed". Throughout the war Hezbollah announced the targeting of civilian homes. On 12 November 2023, Hezbollah fired an anti-tank missile killing an employee of the Israel Electric Corporation who was conducting repair work and injured 13 other Israelis, including six other employees of the Israeli Electric Corporation. The most notable of Hezbollah's attacks on civilians was on 27 July 2024 in the Majdal Shams attack, when Hezbollah fired an Iranian-made Falaq-1 rocket at Majdal Shams, a Druze town in the Golan Heights. The rocket hit a football pitch killing 12 Druze children and injuring at least 42 others. Another attack by Hezbollah resulted in civilian casualties on 9 July 2024, when a rocket struck a couple's car just south of their hometown of Ortal. Additionally, a couple walking their dog in Kiryat Shmona was killed by shrapnel from a Hezbollah rocket on 9 October 2024. On 26 December 2023, a Hezbollah anti-tank missile impacted near a Channel 13 News team while they were interviewing a farmer at Dovev for an article following a prior Hezbollah assault that killed a 56-year-old employee of the Israel Electric Corporation, and injured five workers who were repairing electric lines. Throughout the conflict, Hezbollah fired thousands of inaccurate munitions at Israel and the Golan Heights, killing and injuring civilians and destroying houses.
Clinical trial number NCT02609776 for "Study of Amivantamab, a Human Bispecific EGFR and cMet Antibody, in Participants With Advanced Non-Small Cell Lung Cancer (CHRYSALIS)" at ClinicalTrials.gov Clinical trial number NCT04487080 for "A Study of Amivantamab and Lazertinib Combination Therapy Versus Osimertinib in Locally Advanced or Metastatic Non-Small Cell Lung Cancer (MARIPOSA)" at ClinicalTrials.gov Clinical trial number NCT04988295 for "A Study of Amivantamab and Lazertinib in Combination With Platinum-Based Chemotherapy Compared With Platinum-Based Chemotherapy in Patients With Epidermal Growth Factor Receptor (EGFR)-Mutated Locally Advanced or Metastatic Non- Small Cell Lung Cancer After Osimertinib Failure (MARIPOSA-2)" at ClinicalTrials.gov Clinical trial number NCT04538664 for "A Study of Combination Amivantamab and Carboplatin-Pemetrexed Therapy, Compared With Carboplatin-Pemetrexed, in Participants With Advanced or Metastatic Non-Small Cell Lung Cancer Characterized by Epidermal Growth Factor Receptor (EGFR) Exon 20 Insertions (PAPILLON)" at ClinicalTrials.gov
Sources: en.wikipedia.org
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.
Freezing determines ice crystal size, solute distribution, and the pore network left after drying. A slow or fast freezing rate can produce different cake structures and affect reconstitution. It also sets whether the formulation follows an amorphous or crystalline drying path.
It removes most free water during primary drying and part of the bound water during secondary drying. A small residual moisture content often remains and is specified for each product. Complete removal is generally neither practical nor desirable for stability.
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.