A practical reference on Primary drying: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-11-22. Anything still debated is marked as such rather than presented as settled.
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.
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.
Handling and storage practices aim to keep the cake intact and dry. Vials are typically stored upright at controlled temperatures, often between 2 °C and 8 °C or at -20 °C for longer-term use. Reconstitution involves adding a suitable diluent and gently mixing until the solid dissolves. Shaking or rapid injection of diluent can create foam or damage sensitive molecules. Once reconstituted, the product may require refrigeration and use within a defined period.
Residual moisture is a key quality attribute for lyophilized products. Water that remains after secondary drying can affect chemical stability, cake structure, and shelf life. Karl Fischer titration is a common method for measuring water content in the dried solid. The target range varies by product, but many biologics are dried to between 0.5% and 3% water by weight. Acceptable limits are set during development and confirmed by stability studies.
Stability studies examine how temperature, humidity, and time influence a lyophilized product. Accelerated conditions provide early information about degradation pathways, while long-term studies support shelf-life claims. The glass transition temperature of the dried formulation can indicate its physical stability, and storage above this temperature may increase molecular mobility and lead to collapse or aggregation. Container closure integrity also matters because moisture or oxygen ingress can degrade the product, so vial stoppers and seals are part of the quality system.
| 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. |
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.
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.
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.
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.
== Degradation == Modulation of the effects of ANP is achieved through gradual degradation of the peptide by the enzyme neutral endopeptidase (NEP). Recently, NEP inhibitors have been developed, such as Sacubitril and Sacubitril/valsartan. They may be clinically useful in treating patients in heart failure with reduced ejection fraction .
=== Adhesion to zirconia === Tensile bond strength to zirconia of ethanol solutions that contains MDP were measured. MDP showed high bond strengths to zirconia. Tensile bond strengths of MDP containing resin composites to zirconia ceramic were statistically significantly higher when compared with the bond strength of the conventional Bis-GMA resin composite which contains no adhesive monomer. The mechanisms of coordination between MDP and zirconium oxide were demonstrated by using 1H and 31P magic angle spinning nuclear magnetic resonance (NMR) and two dimensional 1H → 31P heteronuclear correlation NMR. The spectra indicated three possible models as mechanisms of interaction of MDP with zirconia.
One study found that the elimination half-life of hydroxyzine in adults was as short as 3 hours, but this may have just been due to methodological limitations. Although hydroxyzine has a long elimination half-life and acts, in-vivo, as an antihistamine for as long as 24 hours, the predominant CNS effects of hydroxyzine and other antihistamines with long half-lives seem to diminish after 8 hours. Administration in geriatrics differs from the administration of hydroxyzine in younger patients; according to the FDA, there have not been significant studies made (2004), which include population groups over 65, which provide a distinction between elderly aged patients and other younger groups. Hydroxyzine should be administered carefully in the elderly with consideration given to possible reduced elimination.
While negotiating with Alpachi for the hostages' release, Umeko realizes the truth and clears his name, while her teammates rescue Alpachi's son and delete Goldom. Attika Alpachi is voiced by Bin Shimada. Shinnooian Hakutaku (シンノー星人ハクタク, Shinnō Seijin Hakutaku): A wise woman from Planet Shinoo, with knowledge of all space herbs, who occasionally assumes the form of a human teenage girl and possesses a third eye shaped like a red jewel. After the Dekarangers take her into their protective custody, she provides guidance to Sen-chan, becomes attracted to him, and raises money for their wedding. Hakutaku is voiced by Reiko Suzuki (鈴木 れい子, Suzuki Reiko) while her human form is portrayed by Narumi Konno (近野 成美, Kon'no Narumi). Bandarean Jeeva (バンダレ星人ジーバ, Bandare Seijin Jība): A physically imposing Oni-themed alien, and champion boxer in Durden's illegal fight club, from Planet Bandare. After consuming Durden's steroid, Megagesterine, and gaining wing-like horns on his arms and neck, Jeeva fights Hoji, who defeats him. Following this, Jeeva reformed and found work as the assistant director of a television station. Jeeva is voiced by Toshitsugu Takashina (高階 俊嗣, Takashina Toshitsugu). Slorpean Faraway (スロープ星人ファラウェイ, Surōpu Seijin Farawei): A small-time criminal from Planet Slorpe who resembles a ganguro girl and possesses proficient hacking skills.
In July 2023, TikTok launched a new streaming service called TikTok Music. This service allowed users to listen to, download and share songs. After a dispute with TikTok regarding payouts for artists and regulation of AI-generated music content on the platform, Universal Music Group decided not to renew its licensing agreement, causing its catalogue of 3 million recordings to become unavailable for usage after 2024. This marked the company's first instance of withdrawing its music from a major platform, in contrast to Warner Music, which had recently renewed its own licensing deal with TikTok. In March 2024, Universal Music Publishing Group removed its catalogue of 4 million compositions from TikTok. In April 2024, Taylor Swift's music returned to the platform. TikTok Music was discontinued in November 2024. In December 2025, TikTok launched digital gift cards. In February 2026, TikTok launched Local Feed, a feature intended to help users connect with their community and discover local events and updates. In June 2026, TikTok launched Agentic Hub, a platform that integrates third-party AI applications with its advertising system to support campaign creation, management, and performance evaluation. In July 2026, TikTok introduced new AI literacy measures, including educational guides and enhanced content transparency tools, to help users recognize AI-generated content. In August 2026, TikTok introduced a legacy account setting that allows users to decide what happens to their account after their death.
Sources: en.wikipedia.org
== History == The chemical class of barbiturates are one of the oldest sedative-hypnotic agents known, dating back from the introduction of barbital in the early 20th century. In Hungary, hexobarbital (and other barbiturates) were regularly used as drugs by pregnant women attempting suicide. Hexobarbital was long thought to have potentially teratogenic and fetotoxic effects. The FDA has classified them as Pregnancy Category D or C. Some research however, indicate that ingestion of Hexobarbital might cause congenital abnormalities. During World War II, Herta Oberheuser was a Nazi physician and convicted war criminal, investigating the effects of hexobarbital. The experiments were mostly performed on woman prisoners in the Ravensbrück concentration camp.
=== Translation start sites === Using a method developed by Hunt, Shine and Dalgarno showed that the nucleotide tract at the 3' end of E. coli 16S ribosomal RNA (rRNA) (that is, the end where translation begins) is pyrimidine-rich and has the specific sequence 5'-YACCUCCUUA-3'. They proposed that these ribosomal nucleotides recognize the complementary purine-rich sequence 5'-AGGAGGU-3', which is found upstream of the start codon AUG in a number of mRNAs found in viruses that affect E. coli. Many studies have confirmed that base pairing between the Shine–Dalgarno sequence in mRNA and the 3' end of 16S rRNA is of prime importance for initiation of translation by bacterial ribosomes. Given the complementary relationship between rRNA and the Shine–Dalgarno sequence in mRNA, it was proposed that the sequence at the 3'-end of the rRNA determines the capacity of the prokaryotic ribosome to translate a particular gene in an mRNA. Base pairing between the 3'-end of the rRNA and the Shine–Dalgarno sequence in mRNA is a mechanism by which the cell can distinguish between initiator AUGs and internal and/or out-of-frame AUG sequences. The degree of base pairing also plays a role in determining the rate of initiation at different AUG initiator codons.
On March 10, 2014, the first Dunkin' Donuts/Baskin-Robbins combination store in Southern California opened in Ramona. This is Dunkin' Donuts' third California shop to open, following shops in Barstow and on Camp Pendleton. Since March 2014, Dunkin' Donuts has opened several additional locations throughout California, including the Los Angeles area. Dunkin' Donuts shops opened in the San Francisco Bay Area in Walnut Creek, Half Moon Bay, and American Canyon in 2016, as well as South San Francisco and Fremont, in 2017.
== External links == Isotopic effect Measurement In sugar solutions Why measure water activity? at the Wayback Machine (archived 2020-08-07) How to measure water activity? at the Wayback Machine (archived 2020-08-07)
Sources: en.wikipedia.org
=== Otto Mostyn === Otto Mostyn (Roger Barclay) is Henry's godfather, and a fellow classmate of Charles Hanani from Oxford alongside Norton. A sinister, calculating businessman, Otto takes interest in Harper due to her cunning and ruthlessness, and agrees to provide seed funding to LeviathanAlpha, the hedge fund she is starting with Petra Koenig. Otto, Norton, and Aurore are also in a secret cabal to advance their interests via the government. Petra calls Otto after learning that Harper committed insider trading by acting on confidential information she overheard to short Pierpoint. Otto summons Harper to a meeting, where instead of reprimanding her, he tells her he wants her to succeed him in running his investment fund. Harper and Petra ultimately decide to call off the short and end their partnership with Otto to keep their fund above-board, but Harper later teams up with Otto to start her own fund dedicated to shorting corrupt companies over whom she and Otto would have leverage. In series 4, Otto becomes a member of the House of Lords and hopes to obtain a peerage. He puts increasingly strict constraints on Harper's trades at his fund, not wanting her to jeopardize his political connections; she eventually cuts ties with Otto. At Henry's 40th birthday party, Otto receives oral sex from Cordelia, Yasmin's aunt and Charles' sister; it is revealed he also received sexual favors from Charles.
The tubers have a crunchy texture and a sweet, nutty flavour. They can be eaten raw, pickled, dried or cooked. A wide range of uses for this vegetable leads to various dishes in the cuisine of many countries. They can be prepared similarly to Jerusalem artichokes. The leaves can be dried and made into a tea. In Chinese and Japanese cuisine, S. affinis is primarily pickled. In particular, its tuber is a part of Osechi, cooked for celebrating Japanese New Year. Dyed red by leaves of Perilla (red shiso) after being pickled, it is called chorogi. In Korea it is called choseokjam (초석잠). In French cuisine, its cooked tuber is often served alongside dishes named japonaise or Japanese-styled.
action potential The local change in voltage that occurs when the membrane potential of a specific location along the membrane of a cell rapidly depolarizes, such as when a nerve impulse is transmitted between neurons.
Influenced by Fabianism as well as Marxism-Leninism, the CSP included advocates of armed struggle or sabotage (such as Yusuf Meherally, Jayaprakash Narayan, and Basawon Singh (Sinha) as well as those who insisted upon Ahimsa or Nonviolent resistance (such as Acharya Narendra Deva). The CSP advocated decentralized socialism in which co-operatives, trade unions, independent farmers, and local authorities would hold a substantial share of the economic power.
In biology, developmental bioelectricity is the regulation of cell, tissue, and organ-level patterning and behavior by electrical signals during the development of embryonic animals and plants. The charge carrier in developmental bioelectricity is the ion (a charged atom) rather than the electron, and an electric current and field is generated whenever a net ion flux occurs. Cells and tissues of all types use flows of ions to communicate electrically. Endogenous electric currents and fields, ion fluxes, and differences in resting potential across tissues comprise a signalling system. It functions along with biochemical factors, transcriptional networks, and other physical forces to regulate cell behaviour and large-scale patterning in processes such as embryogenesis, regeneration, and cancer suppression.
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.
Residual moisture can influence chemical degradation, cake collapse, and long-term stability. Low moisture levels usually improve stability, but each product has an optimal range.