Residual moisture comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-11-17. Numbers and descriptions here follow the published literature rather than marketing material.
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.
| 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. |
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.
Freeze-drying is distinct from simple evaporation and from spray drying. Evaporation removes water at temperatures above freezing, while spray drying rapidly dries droplets in a heated gas stream. Lyophilization avoids high temperatures, which can be useful for heat-sensitive materials such as proteins, vaccines, and some foods. The porous cake produced by sublimation dissolves or rehydrates more quickly than a dense dried mass. Not all materials tolerate freezing or the pH shifts that can occur as solutes concentrate during ice formation.
Quality control also examines cake structure, color, and reconstitution behavior. A collapsed or shrunken cake can indicate a thermal excursion during drying. Analytical methods such as X-ray diffraction, differential scanning calorimetry, and near-infrared spectroscopy can detect crystallinity or moisture distribution. Regulatory expectations focus on validated assays and lot-to-lot consistency. Questions remain about how well accelerated stability tests predict long-term behavior for every formulation. Visual inspection remains common but is subjective without trained reviewers and reference images.
After lyophilization, a product's quality depends on residual moisture, cake appearance, and reconstitution time. Residual moisture is often measured by Karl Fischer titration or thermogravimetric analysis. A low moisture content can slow chemical degradation, but overly dry cakes may be brittle or slow to dissolve. Stability studies track these attributes over months under defined temperature and humidity conditions. Batch records link these measurements to specific process runs and help identify trends before a product fails specification.
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.
Although the term was coined in the late 1980s one of the first retroactively recognized examples of a killer application is the VisiCalc spreadsheet, released in 1979 for the Apple II. Because it was not released for other computers for 12 months, people spent US$100 (equivalent to $400 in 2025) for the software first, then $2,000 to $10,000 (equivalent to $9,000 to $44,000) on the requisite Apple II. Byte wrote in 1980, "VisiCalc is the first program available on a microcomputer that has been responsible for sales of entire systems", and Creative Computing's VisiCalc review is subtitled "reason enough for owning a computer". Others also chose to develop software, such as EasyWriter, for the Apple II first because of its higher sales, helping Apple defeat rivals Commodore International and Tandy Corporation. The co-creator of WordStar, Seymour Rubinstein, argued that the honor of the first killer app should go to that popular word processor, given that it came out a year before VisiCalc and that it gave a reason for people to buy a computer. However, whereas WordStar could be considered an incremental improvement (albeit a large one) over smart typewriters like the IBM Electronic Selectric Composer, VisiCalc, with its ability to instantly recalculate rows and columns, introduced an entirely new paradigm and capability unavailable on larger computers. Lotus 1-2-3 similarly benefited sales of the IBM PC. Noting that computer purchasers did not want PC compatibility as much as compatibility with certain PC software, InfoWorld suggested "let's tell it like it is.
== References == Aldose reductase inhibitor for treatment of diabetic complications. Prepn (stereo unspec): M. Kurono, et al., EP 193415; eidem, US 4740517 (1986, 1988 both to Sanwa) Prepn of isomers: T. Yamaguchi et al., Arzneim.-Forsch. 44, 344 (1994) Pharmacological profile: K. Mizuno et al. in Current Concepts of Aldose Reductase and Its Inhibitions, N. Sakamoto et al., Eds. (Elsevier, Amsterdam, 1990) pp 89–96. Configuration and crystal structure of complex with aldose reductase: M. Oka et al., J. Med. Chem. 43, 2479 (2000). Clinical efficacy in diabetic peripheral neuropathy: N. Hotta et al., Diabetes Care 24, 1776 (2001). Clinical suppression of sorbitol accumulation in erythrocytes of diabetic patients: T. Asano et al., J. Diabetes Complications 16, 133 (2002); eidem, ibid. 18, 336 (2004). Review of clinical development: N. Giannoukakis, Curr. Opin. Invest. Drugs 4, 1233-1239 (2003).
=== Cardiovascular disease === Cardiovascular disease can present itself in many different forms, from cardiomyopathy to peripheral arterial disease, and heart disease remains a key threat to human health. While there are means of therapy to both prevent and cure cardiovascular diseases, many drugs are unavailable for clinical use due to severe side effects in addition to high toxicity levels. However, in the past decade, sv-LAAOs have shown promise in affecting platelet aggregation. It has been proposed that hydrogen peroxide is considered to play a significant role regarding the enzymes ability to both cause and prevent this platelet aggregation. With this knowledge, it appears that sv-LAAOs could be evaluated as a potential cardiovascular disease therapeutic because of their biological potency.
On 16 April 1973, Gaddafi proclaimed the start of a "Popular Revolution" in a speech at Zuwarah. He initiated this with a five-point plan, the first point of which dissolved all existing laws, to be replaced by revolutionary enactments. The second point proclaimed that all opponents of the revolution had to be removed, while the third initiated an administrative revolution that Gaddafi proclaimed would remove all traces of bureaucracy and the bourgeoisie. The fourth point announced that the population must form People's Committees and be armed to defend the revolution, while the fifth proclaimed the beginning of the Cultural Revolution in Libya, to expunge the country of "poisonous" foreign influences. He began to lecture on this new phase of the revolution in Libya, Egypt, and France. As a process, it had many similarities with the Cultural Revolution implemented in China. As part of this Popular Revolution, Gaddafi invited Libya's people to found General People's Committees as conduits for raising political consciousness. Although offering little guidance for how to set up these councils, Gaddafi claimed that they would offer a form of direct political participation that was more democratic than a traditional party-based representative system. He hoped that the councils would mobilize the people behind the RCC, erode the power of the traditional leaders and the bureaucracy, and allow for a new legal system chosen by the people.
On the other hand, the findings of animal studies of methenamine and carcinogenicity have also been questioned by some authors, though this topic is controversial. Antibiotics are known to disrupt the gut, urinary tract, and vaginal microbiota. This has been associated with increased risk of recurrent UTIs. Methenamine has been limitedly studied in this regard, but was found in one small study to preserve urinary microbial diversity. However, more studies are needed to assess the influence of methenamine on the host microbiome, both in the urinary tract and elsewhere in the body. Side effects of the topical form of methenamine for hyperhidrosis include dry skin, among others.
Sources: en.wikipedia.org
In August 2015, Arby's introduced a series of five small sandwiches called Sliders starting at $1.29, with prices varied by location. These new menu items led to an increase in sales at many locations. This is not the first time Arby's tried to market miniature sandwiches. Two years earlier, Arby's tried to sell a similar product called the Mighty Minis that were sold in pairs. During the first month of national sales, the firm was able to sell 1 million or a ton of sliders. To encourage additional sales outside normal lunch and dinner meal hours, began to offer sliders and small size drinks and sides at the reduced price of $1 between the hours of 2 and 5 p.m. starting in October 2015. Due to Arby's great success in the increase of sales created by the introduction of this new product line, Nation's Restaurant News awarded Arby's its MenuMasters Award for 2016. The Turkey 'n Cheese was initially offered as a limited time menu item in December 2016 but was shown to be popular enough to be retained on the regular menu. A Pizza Slider was introduced as a limited time menu item in May 2017. In late August 2016, Arby's introduced four chicken sandwiches that used a buttermilk-based breaded breast filet. Arby's debuted a new sandwich known as Smokehouse Pork Belly Sandwich in October 2016.
== Physiological functions == The sites of APLNR receptor expression are linked to the different functions played by Elabela in the organism. Despite that, Elabela is capable of signaling independently of APLNR in human embryonic stem cells and certain cancer cell lines including OVISE.
=== Persons with disabilities === During 2025, the Karnataka Labour Department worked on a proposed legislative framework for reservations for persons with disabilities in education and private-sector employment. The draft framework proposed up to 10 percent reservation in educational institutions and 5 percent in private-sector employment, subject to legislative and policy processes.
The Court of Justice held that the Directive could be relied on by her because equality was also a general principle of EU law. Fourth, if the defendant is an emanation of the state, even if not central government, it can still be bound by Directives. In Foster v British Gas plc the Court of Justice held that Mrs Foster was entitled to bring a sex discrimination claim against her employer, British Gas plc, which made women retire at age 60 and men at 65, if (1) pursuant to a state measure, (2) it provided a public service, and (3) had special powers. This could also be true if the enterprise is privatised, as it was held with a water company that was responsible for basic water provision. Fifth, national courts have a duty to interpret domestic law "as far as possible in the light of the wording and purpose of the directive". Textbooks (though not the Court itself) often called this "indirect effect". In Marleasing SA v La Comercial SA the Court of Justice held that a Spanish Court had to interpret its general Civil Code provisions, on contracts lacking cause or defrauding creditors, to conform with the First Company Law Directive article 11, that required incorporations would only be nullified for a fixed list of reasons. The Court of Justice quickly acknowledged that the duty of interpretation cannot contradict plain words in a national statute. But, if a member state has failed to implement a Directive, a citizen may not be able to bring claims against other non-state parties. It must instead sue the member state itself for failure to implement the law.
Sources: en.wikipedia.org
Emissions from vehicles such as cars and trucks can be a substantial outdoor source of PAHs in particulate air pollution. Geographically, major roadways are thus sources of PAHs, which may distribute in the atmosphere or deposit nearby. Catalytic converters are estimated to reduce PAH emissions from gasoline-fired vehicles by 25-fold. People can also be occupationally exposed from using fossil fuels or their derivatives, wood-burning, carbon electrodes, or exposure to diesel exhaust. Industrial activity that can produce and distribute PAHs includes aluminum, iron, and steel manufacturing; coal gasification, tar distillation, shale oil extraction; production of coke, creosote, carbon black, and calcium carbide; road paving and asphalt manufacturing; rubber tire production; manufacturing or use of metal working fluids; and activity of coal or natural gas power stations. In industrial countries, people who smoke tobacco products, or who are exposed to second-hand smoke, are among the most highly exposed groups; tobacco smoke contributes to 90% of indoor PAH levels in the homes of smokers. For the general population in developed countries, the diet is otherwise the dominant source of PAH exposure, particularly from smoking or grilling meat or consuming PAHs deposited on plant foods, especially broad-leafed vegetables, during growth. Exposure also occurs through drinking alcohol aged in charred barrels, flavored with peat smoke, or made with roasted grains. PAHs are typically at low concentrations in drinking water.
Druze leaders: The Sheikh al-'Aql, Hikmat al-Hijri, called on Druze fighters to "resist this brutal campaign by all available means", the main sheikh of the Druze in Israel, Muwaffaq Tarif, declared, "The eyes and hearts of the Israeli Druze community are focused on the suffering of the Druze villages around Damascus", although he distanced himself from al-Hijri. Supreme Alawite Islamic Council: The Sheikh Ghazal Ghazal, the leader of the Supreme Alawite Islamic Council, pointed to the attacks against churches and members of the Druze community, emphasizing that "the perpetrator is the same, and the blood is the same". He stated that what the Alawite community has suffered has also affected other sects. Saraya Ansar al-Sunnah: The group threatened on 15 July to expand its sectarian attacks to include the Druze community in Suwayda. Islamic State: Abu Hudhayfa's group, affiliated with ISIS, declared that the Druze "violated the honor of Sunni Muslims," and that the goal of the attack was to kill the "infidel Druze". Minbar Ansar Al-Rasoul: The group celebrated the "victory" of the Internal Security Forces over the Druze protesters in Jaramana.
In the UK no formal qualification or certification is required prior to becoming a phlebotomist as training is usually provided on the job. The NHS offers training with formal certification upon completion.
Antagonism of the α1-adrenergic receptor is thought to cause orthostatic hypotension and dizziness. Inhibition of muscarinic acetylcholine receptors is responsible for the anticholinergic side effects of clomipramine like dry mouth, constipation, urinary retention, blurred vision, and cognitive/memory impairment. In overdose, sodium channel blockade in the brain is believed to cause the coma and seizures associated with TCAs while blockade of sodium channels in the heart is considered to cause cardiac arrhythmias, cardiac arrest, and death. On the other hand, sodium channel blockade is also thought to contribute to the analgesic effects of TCAs, for instance in the treatment of neuropathic pain. The exceptionally strong serotonin reuptake inhibition of clomipramine likely precludes the possibility of its antagonism of serotonin receptors (which it binds to with more than 100-fold lower affinity than the SERT) resulting in a net decrease in signaling by these receptors. In accordance, while serotonin receptor antagonists like cyproheptadine and chlorpromazine are effective as antidotes against serotonin syndrome, clomipramine is nonetheless capable of inducing this syndrome. In fact, while all TCAs are SRIs and serotonin receptor antagonists to varying extents, the only TCAs that are associated with serotonin syndrome are clomipramine and to a lesser extent its dechlorinated analogue imipramine, which are the two most potent SRIs of the TCAs (and in relation to this have the highest ratios of serotonin reuptake inhibition to serotonin receptor antagonism).
== Medical uses == In the US and the EU, adalimumab is indicated for the treatment of rheumatoid arthritis, juvenile idiopathic arthritis, psoriatic arthritis, ankylosing spondylitis, adult and pediatric Crohn's disease, ulcerative colitis, plaque psoriasis, hidradenitis suppurativa, and uveitis. In the EU it is also indicated for chronic aggressive progressive pulmonary and bone sarcoidosis.
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.
Sealed vials or containers should be kept at the temperature specified by stability data, often controlled room temperature or 2–8 °C. Moisture and oxygen barriers are important because both can degrade sensitive materials. Opened containers may need immediate use or protection from ambient humidity.