If you have been reading about Sublimation and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-12-14. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
Lyophilization, also called freeze-drying, is a dehydration process in which a solvent, usually water, is frozen and then removed by sublimation under reduced pressure. The method preserves heat-sensitive materials that would degrade in conventional drying. Large-scale use grew during the mid-twentieth century for blood plasma and antibiotics, and it later expanded to vaccines, enzymes, foods, and advanced materials. The process produces a dry, porous solid that usually reconstitutes rapidly. It is distinct from simple evaporation because the solvent bypasses the liquid phase during primary removal.
| Property | Value | Notes |
|---|---|---|
| Process name | Lyophilization or freeze-drying | Both terms appear in technical standards and literature. |
| Phase transition | Sublimation | Solid ice becomes vapor without a liquid step. |
| Typical chamber pressure | 0.05-0.5 mbar | Range depends on product temperature and equipment. |
| Typical product temperature | -40 °C to -10 °C | Measured during primary drying; formulation sets limits. |
| Water content after drying | 0.5-3% w/w | Target varies by material and stability needs. |
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 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.
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.
Kanury Rao also known as Kanury Venkata Subba Rao (born 1958) is an Indian immunologist. He was the head of the Drug Discovery Research Centre (DDRC) at the Translational Health Science and Technology Institute (THSTI) Faridabad. He is known for his studies in the fields of peptide synthesis and cell signaling and the design of synthetic peptide vaccines. He is an elected fellow of the Indian Academy of Sciences, National Academy of Sciences, India and the Indian National Science Academy. and a recipient of several awards including the Millennium Plaque of Honour of the Indian Science Congress and the National Bioscience Award for Career Development. The Council of Scientific and Industrial Research awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, in 1997, for his contributions to biological sciences.
== Medical uses == Approved indication for dihydrocodeine is the management of moderate to moderately severe pain as well as coughing and shortness of breath. As is the case with other drugs in this group, the antitussive dose tends to be less than the analgesic dose, and dihydrocodeine is a powerful cough suppressant like all other members of the immediate codeine family (see below) and their cousins hydrocodone, oxycodone and ethylmorphine, whole opium preparations, and the strong opioid hydromorphone. For use against pain, dihydrocodeine is usually formulated as tablets or capsules containing 15–16 mg or 30–32 mg with or without other active ingredients such as aspirin, paracetamol (acetaminophen), ibuprofen, or others. Controlled release dihydrocodeine is available for both pain and coughing, as indicated below, as waxy tablets containing 60 to 120 mg of the drug. Some formulations, intended for use against coughing and the like, have other active ingredients such as antihistamines, decongestants and others. Other oral formulations, such as packets of effervescent powder, sublingual drops, elixirs and the like are also available in many locations. Injectable dihydrocodeine is most often given as a deep subcutaneous injection. Dihydrocodeine appears to be superior to tramadol in treating pain.
Biden said, "I view myself as a transition candidate." On August 11, Biden announced Kamala Harris as his running mate, making her the first African American and first South Asian American vice-presidential nominee on a major-party ticket. On August 18, at the 2020 Democratic National Convention, Biden officially became the Democratic Party nominee for president in the 2020 election.
== Connections with Mauritania == In testimony given by Antonio Panzeri in February 2023, he and Francesco Giorgi received €200,000 from Mauritania to improve the image of the country in the EU, as requested by then-president, Mohamed Ould Abdel Aziz in 2018. Aziz left office in 2019, with Mohamed Ould Ghazouani winning the election to become president. Paid €50,000 per annum from 2019, Panzeri helped organise an international conference in Mauritania in June 2022. Mauritania only abolished slavery in 1981 and had been criticised by the EU for their human rights record, yet received millions annually from the EU to host fishing vessels. Marie Arena, as head of the EU subcommittee on human rights, proposed the conference and invited Panzeri, who was no longer an MEP to attend. Panzeri and Giorgi were speakers and Andrea Cozzolino also attended, Arena and Cozzolino meeting with the President of Mauritania, Ghazouani.
Sources: en.wikipedia.org
==== Illegal marketing of gabapentin for off-label uses settlement (2004) ==== In 1993, the Food and Drug Administration (FDA) approved gabapentin only for treatment of seizures. Warner–Lambert, which merged with Pfizer in 2000, used continuing medical education and medical research, sponsored articles about the drug for the medical literature, and alleged suppression of unfavorable study results, to promote gabapentin. Within five years, the drug was being widely used for off-label uses such as treatment of pain and psychiatric conditions. Warner–Lambert admitted to violating FDA regulations by promoting the drug for pain, psychiatric conditions, migraine, and other unapproved uses. In 2004, the company paid $430 million in one of the largest settlements to resolve criminal and civil health care liability charges. It was the first off-label promotion case successfully brought under the False Claims Act. A Cochrane review concluded that gabapentin is ineffective in migraine prophylaxis. The American Academy of Neurology rates it as having unproven efficacy, while the Canadian Headache Society and the European Federation of Neurological Societies rate its use as being supported by moderate and low-quality evidence.
== Positions held == 1998 – Elected councilor, Sandur Town Panchayat 2004 – Elected MLA from Sandur representing Janata Dal (Secular) 2007 – Joined Indian National Congress 2008 – Elected MLA from Kalaghatgi representing Indian National Congress 2010 – Appointed general secretary of KPCC 2010 – Appointed Raichur District in charge by KPCC 2013 – Wins second time in a row as MLA from Kalaghatgi 2013 – Appointed Minister of State for Information and Infrastructure 2023 - Appointed Labour minister of Karnataka. 2026- Appointed Labour and Employment minister of Karnataka.
In April 1918, after the German-Russian Treaty of Brest-Litovsk, Austrian Foreign Minister Count Ottokar Czernin made a speech attacking incoming French Prime Minister Georges Clemenceau as being the main obstacle to a peace favouring the Central Powers. Clemenceau was incensed and, after seeing Emperor Charles's letter of 24 March 1917, had it published. For a while, the life of Sixtus appeared to be in danger, and there were even fears that Germany might occupy Austria. Czernin persuaded Charles to send a 'Word of Honour' to Austria's allies saying that Sixtus had not been authorised to show the letter to the French Government, that Belgium had not been mentioned, and that Clemenceau had lied about the mention of Alsace. Czernin had actually been in contact with the German Embassy throughout the whole crisis and attempted to persuade the Emperor to step down because of the Affair. After failing to do so, Czernin resigned as Foreign Minister.
==== Gram-negative bacteria ==== Outer membrane vesicles (OMVs), that can transfer DNA between bacterial cells, are produced by metabolically active bacterial cells, and the OMVs are not the result of cell lysis or cell death. Pathogenic strains can produce about 10-25 times more vesicles than a nonpathogenic strain making this highly relevant to carbapenem resistance transfer. OMVs protect plasmids from being digested extracellularly by nucleases that may be found in the environment, thus favoring horizontal gene transfer.
== Firazyr (icatibant) == Jerini's lead compound Firazyr (icatibant), is an inhibitor of the action of the hormone bradykinin on its B2 receptor. This compound was in-licensed from Aventis in 2001. It has been approved for hereditary angioedema in all member states of the European Union in July 2008. The drug was granted FDA approval on August 25, 2011.
Sources: en.wikipedia.org
The percentage of the Portuguese population suffering from moderate or severe food insecurity between 2022 and 2024 was on average 11.9%, which makes Portugal the third-highest country in Southern Europe for this indicator where the average stands at 5.9%. Stakeholders have raised concerns over the effectiveness of food safety policies.
==== Antitumorigenic activities ==== Honokiol has shown pro-apoptotic effects in melanoma, sarcoma, myeloma, leukemia, bladder, lung, prostate, oral squamous cell carcinoma, in glioblastome multiforme cells and colon cancer cell lines. Honokiol inhibits phosphorylation of Akt, p44/42 mitogen-activated protein kinase (MAPK), and src. Additionally, honokiol regulates the nuclear factor kappa B (NF-κB) activation pathway, an upstream effector of vascular endothelial growth factor (VEGF), MCL1, and cyclooxygenase 2 (COX-2), all significant pro-angiogenic and survival factors. Honokiol induces caspase-dependent apoptosis in a TRAIL-mediated manner, and potentiates the pro-apoptotic effects of doxorubicin and other etoposides. So potent is honokiol's pro-apoptotic effects that it overcomes even notoriously drug resistant neoplasms such as multiple myeloma and chronic B-cell leukemia. Honokiol also acts on the PI3K/mTOR pathway in tumor cells while maintaining pathway activity in T cells.
The case Blizzard Entertainment v. Valve Corporation was settled out of court in May 2012; Valve retained the right to use Dota commercially, while Blizzard reserved the right for fans to use Dota non-commercially. Blizzard changed the names of its own projects to remove the Dota term, and renamed Blizzard All-Stars as Heroes of the Storm. Valve's Dota 2 was released in 2013. In 2014, mobile developers Lilith and uCool released its games Dota Legends and Heroes Charge, respectively. Both were influenced by Dota and the sequels. In 2017, Valve and Blizzard took joint action against these companies, citing copyright issues related to the Dota names. uCool argued that the Dota games were a collective work and could not be copyrighted by anyone in particular, but the presiding judge, Charles R. Breyer, felt that, due to the trio's actions as maintainers of the Dota mods, they had a rightful copyright claim to this. Separately, Lilith and uCool argued that Eul had, in a forum post from September 2004, assigned an open-source copyright license to Dota, which would make Valve and Blizzard's copyright claims void. The case was later heard by a jury.
Estrone levels surpass estradiol levels at around 2 hours post-dose and reach a maximum at about 4 hours. It has been speculated that the high delayed levels of estrone with sublingual estradiol may be due to the rich lymphatic drainage in the neck region, which may result in estradiol being taken up by the reticuloendothelial system and then metabolized into estrone. Sublingual administration of a single 0.25 mg tablet of micronized estradiol has been found to produce peak levels of 300 pg/mL estradiol and 60 pg/mL estrone within 1 hour. A higher dose of 1 mg estradiol was found to result in maximum levels of 450 pg/mL estradiol and 165 pg/mL estrone, which was followed by a rapid decline in estradiol levels to 85 pg/mL within 3 hours. Conversely, the decline in estrone levels was much slower and reached a level of 80 pg/mL after 18 hours. A single administration of 4 mg micronized estradiol (two 2-mg Estrace tablets) under the tongue, considered a very high dose of sublingual estradiol, has been found to result in maximal levels of estradiol of 1759 ± 704 pg/mL, with a range of 634 to 2840 pg/mL, after 1 hour in a mixed group of normotensive and hypertensive postmenopausal women. A replication of this study using the same dosage and protocols measured estradiol levels of 2227 ± 1180 pg/mL for the whole group of women but found that estradiol levels between the normotensive and hypertensive groups were significantly different at 1790 ± 869 pg/mL and 2664 ± 1490 pg/mL, respectively.
Sources: en.wikipedia.org
Conventional drying uses heat to evaporate liquid water, often at temperatures that can degrade sensitive materials. Lyophilization freezes the material first and then removes water by sublimation under vacuum. This avoids prolonged exposure to liquid water and high heat.
Lowering pressure reduces the boiling point of water and allows ice to sublimate at temperatures below freezing. Vacuum also limits convective heat transfer, so heat is usually supplied by shelves or radiation. The pressure must stay below the vapor pressure of ice at the product temperature.
The cycle typically includes freezing, primary drying, and secondary drying. Freezing solidifies water and sets the pore structure; primary drying removes bulk ice; secondary drying removes bound water. Some cycles add annealing or pre-freezing steps.
Yes. Lyophilization and freeze-drying are synonyms for the same vacuum-assisted sublimation process. The term lyophilization is more common in pharmaceutical and laboratory settings, while freeze-drying is widely used in food and general contexts.