If you have been reading about lyophilization 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 2025-12-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Lyophilization is a dehydration technique in which a product is frozen and the solvent is removed under reduced pressure. The low pressure allows ice to sublimate directly into vapor without passing through a bulk liquid phase. This differs from conventional drying, where heat drives evaporation and can damage heat-sensitive structures. The process is used for biological materials, pharmaceutical formulations, and some foods. Its main advantage is preservation of porous structure and rapid reconstitution.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | freeze-drying, lyophilisation, cryodesiccation | Lyophilization is common in pharmaceutical literature. |
| Typical chamber pressure during primary drying | 0.05–0.5 mbar (5–50 Pa) | Must remain below the triple point of water. |
| Typical shelf temperature during freezing | −40 to −20 °C | Lower temperatures may be used for eutectic systems. |
| Typical residual moisture after secondary drying | 0.5–3% w/w | Product-dependent; low moisture improves stability but can cause over-drying. |
| Typical analytical method for residual moisture | Karl Fischer titration or loss on drying | Thermogravimetric methods are also used. |
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.
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.
Dulaglutide, sold under the brand name Trulicity, is a medication used for the treatment of type 2 diabetes in combination with diet and exercise. This medication is often prescribed for adults and children age 10 and older with type 2 diabetes (citation). It is utilized alongside diet and exercise in order to improve blood sugar. It is also approved in the United States for the reduction of major adverse cardiovascular events such as death, heart attack, or stroke in adults with type 2 diabetes who have established cardiovascular disease or multiple cardiovascular risk factors. It is not yet known if it is beneficial, safe, or effective in lowering blood sugar in children under 10 years of age. Trulicity is taken by giving an injection once a week under the skin of your stomach, thigh, or upper arm. The medication is a prescription that comes in the form of a pre-filled single-dose pen in 0.75mg, 1.5mg, 3mg, or 4.5mg per 5mg injection. You are able to take the dosage at any time during the day of administration with/without food eaten. The most common side effects upon administration are nausea, diarrhea, vomiting, abdominal pain, and decreased appetite. Dulaglutide injection is in a class of medications called incretin mimetics, as it is a glucagon-like peptide-1 receptor agonist (GLP-1 agonist) consisting of GLP-1(7-37) covalently linked to an Fc fragment of human IgG4. GLP-1 is a hormone that is involved in normalizing the level of glucose in blood (glycemia). It works by aiding the pancreas to release the correct amount of insulin when blood sugar levels are high.
== External links == Picture of Margaret Oakley Dayhoff, c. 1980. Owned by her daughter Ruth E. Dayhoff, M.D. Made available by the National Library of Medicine. Profile and photographs of Margaret O. Dayhoff in Grandma got STEM project. Information submitted to the project by Margaret Dayhoff's son-in-law Vincent, husband of Ruth E. Dayhoff. Also contains biographical information about descendants. Baby Joseph and Vrundha M. Nair .2012 Woman Innovator in Bioinformatics: Dr. Margaret Oakley Dayhoff. Adv Bio Tech:12 (01) 32–34
Dingane's army then attacked and massacred a group of 250 Voortrekker men, women and children camped nearby. The site of this massacre is today called Weenen, (Dutch for "to weep"). The remaining Voortrekkers elected a new leader, Andries Pretorius, who led a successful defence of the Voortrekker position from the Zulu forces and Dingane at the Battle of Blood River on 16 December 1838, when 15,000 Zulu impis (warriors) attacked a group of 470 Voortrekker settlers led by Pretorius.
Sources: en.wikipedia.org
With respect to Averroes’s view, what, if only I knew, could necessitate that we not say this very thing in the case of bodies that come to be and pass away, namely, that the matter they contain is their corporeality, and their form the form that is specific to each one and serves each one as the perfection of its corporeality? Corporeality, which he calls “corporeal form,” would then function as matter with respect to its specific form. If so, the matter, even without its specific form, would be in need of a place and would exist in actuality. Behold, my witness is in heaven, since the celestial body, which is a body without matter, is one that exists in actuality. In this way, many difficult and perplexing questions regarding hylic nature as it is generally understood will be resolved. It is open, therefore, to an objector to say that it is not a specific form through which a body exists, but that the corporeal form, which is the substratum in actuality, is that which sustains the specific form Hasdai Crescas imagines that celestial-body is like Hylé but as matter in actuality, sure over the opposition about this, i.e. in potential existence. Matter and form is always presents in all but celestial-bodies are without form because of their nature; so Hasdai Crescas finds the solution also about this paradox.
Corals predominantly reproduce sexually. About 25% of hermatypic corals (reef-building stony corals) form single-sex (gonochoristic) colonies, while the rest are hermaphroditic. It is estimated more than 67% of coral are simultaneous hermaphrodites.
== External links == Clinical trial number NCT04020341 for "A Study to Evaluate Efficacy and Safety of Gepotidacin in the Treatment of Uncomplicated Urinary Tract Infection (UTI)" at ClinicalTrials.gov Clinical trial number NCT04187144 for "Comparative Study to Evaluate Efficacy and Safety of Gepotidacin to Nitrofurantoin in Treatment of Uncomplicated Urinary Tract Infection (UTI)" at ClinicalTrials.gov
Sources: en.wikipedia.org
=== Pulmonary function test === The forced vital capacity may be monitored at intervals to detect increasing muscular weakness. Acutely, negative inspiratory force may be used to determine adequacy of ventilation; it is performed on those individuals with MG.
The judiciary of the EU has played an important role in the development of EU law. It interprets the treaties, and has accelerated economic and political integration. Today the Court of Justice of the European Union (CJEU) is the main judicial body, within which there is a higher Court of Justice that deals with cases that contain more public importance, and a General Court that deals with issues of detail but without general importance, and then a separate Court of Auditors. Under the Treaty on European Union article 19(2) there is one judge from each member state in the Court of Justice and General Court (27 on each at present). Judges should "possess the qualifications required for appointment to the highest judicial offices" (or for the General Court, the "ability required for appointment to high judicial office"). A president is elected by the judges for three years. While TEU article 19(3) says the Court of Justice is the ultimate court to interpret questions of EU law, in practice, most EU law is applied by member state courts (e.g. the German Bundesgerichtshof, the Belgian Cour du travail, and formerly the English Court of Appeal). Member state courts can refer questions to the CJEU for a preliminary ruling. The CJEU's duty is to "ensure that in the interpretation and application of the Treaties the law is observed", although realistically it has the ability to expand and develop the law according to the principles it develops consistently with democratic values.
==== Protein reduction ==== In order to combat uraemia, the amount of protein in the diet and thus the amount of nitrogen supplied to the body can be reduced. However, this is only possible to a limited extent in cats, as their energy balance is dependent on protein (see above). The protein content should be adjusted to the maintenance requirement of 15 g digestible crude protein per MJ UE and should never be reduced below 11 g/MJ UE, whereby the amount of protein declared on feed must be multiplied by a factor of 0.86 to obtain the digestible crude protein. High-quality animal protein also reduces the amount of nitrogen compounds entering the large intestine and thus the amount of ammonia produced by bacterial degradation processes through the intestinal flora. If there are severe acceptance problems or there is a loss of body mass and muscle, complicating factors (metabolic acidosis, intestinal bleeding) must be clarified. The necessary nutritional requirements must be guaranteed in any case, in problematic cases even without a kidney diet.
Sources: en.wikipedia.org
Yes, the terms are generally interchangeable. Lyophilization is more common in pharmaceutical and laboratory contexts, while freeze-drying appears widely in food science and general writing. Both describe removal of solvent by sublimation under vacuum after freezing.
Reduced pressure keeps the process below the triple point of water, so ice can sublimate directly to vapor. It also lowers the temperature needed for drying, which helps preserve heat-sensitive materials. Without vacuum, melting or boiling could occur instead of controlled sublimation.
The rate depends on heat transfer to the product and mass transfer of vapor through the dried layer. A cold condenser, adequate vacuum, and suitable shelf temperature all influence speed. Formulation properties such as solid content and collapse temperature also set practical limits.
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.