If you have been reading about Reconstitution 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 2025-11-14. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Quality control for lyophilized materials includes visual inspection, residual moisture measurement, and reconstitution testing. Cake appearance can reveal process problems such as collapse, shrinkage, or meltback, although appearance alone does not prove potency. Residual moisture is commonly measured by Karl Fischer titration or by loss on drying. Reconstitution time is checked because a slow or incomplete dissolve can indicate a change in pore structure. Stability studies track these attributes over time under defined temperature and humidity conditions.
Analytical methods for lyophilized solids must account for the low moisture content and the fragile cake. Karl Fischer titration is widely used for water content, while near-infrared spectroscopy can measure moisture non-destructively in sealed containers. X-ray diffraction and modulated differential scanning calorimetry help identify crystalline or amorphous phases. Residual solvent analysis may be needed if organic solvents were used during formulation. The combination of these methods supports batch release and long-term stability assessment.
| 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. |
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.
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.
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.
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.
=== Crystal modification === Some antiscalants alter the crystal structure of scale-forming salts, making them less likely to adhere to surfaces and form stubborn deposits. At a submicroscopic level, these soft non-adherent scales with antiscalant use would appear distorted, more oval in shape, and less compact.
K84 produces a bacteriocin (agrocin 84) which is an antibiotic specific against related bacteria, including A. tumefaciens. This method, which was successful at controlling the disease on a commercial scale, had the risk of K84 transferring its resistance gene to the pathogenic Agrobacteria. Thus, in the 1990s, a deletion mutant strain based on K84, known as K1026, was created. This strain is just as successful in controlling crown gall as K84 without the caveat of resistance gene transfer.
Osteohistological research on the American black bear has shown that skeletal integrity during hibernation is maintained through region-specific microstructural responses, with weight-bearing limb bones retaining dense cortical organization while axial elements exhibit increased internal remodeling, consistent with differential functional demands during prolonged inactivity. The body temperature does not drop significantly, like other mammalian hibernators (staying around 35 °C (95 °F)) and they remain somewhat alert and active. If the winter is mild enough, they may wake up and forage for food. Females also give birth in February and nurture their cubs until the snow melts. During winter, American black bears consume 25–40% of their body weight. Researchers have found that bears have adaptive reversible insulin resistance. During their fattening phase bears become hypersensitive to insulin but in the winter they switch and become more insulin resistant, as well as activating anti-inflammatory genes to resist kidney damage. Many of the physiological changes an American black bear exhibits during hibernation are retained slightly post-hibernation. Upon exiting hibernation, bears retain a reduced heart rate and basal metabolic rate. The metabolic rate of a hibernating bear will remain at a reduced level for up to 21 days after hibernation. After emerging from their winter dens in spring, they wander their home ranges for two weeks so that their metabolism accustoms itself to the activity.
Most SDS-PAGE protein separations are performed using a "discontinuous" (or DISC) buffer system that significantly enhances the sharpness of the bands within the gel. During electrophoresis in a discontinuous gel system, an ion gradient is formed in the early stage of electrophoresis that causes all of the proteins to focus on a single sharp band in a process called isotachophoresis. Separation of the proteins by size is achieved in the lower, "resolving" region of the gel. The resolving gel typically has a much smaller pore size, which leads to a sieving effect that now determines the electrophoretic mobility of the proteins.
Sources: en.wikipedia.org
More recently gene therapy has been attempted as an alternative to the bone marrow transplant. Transduction of the missing gene to hematopoietic stem cells using viral vectors is being tested in ADA SCID and X-linked SCID. In 1990, four-year-old Ashanthi DeSilva became the first patient to undergo successful gene therapy. Researchers collected samples of DeSilva's blood, isolated some of her white blood cells, and used a retrovirus to insert a healthy adenosine deaminase (ADA) gene into them. These cells were then injected back into her body, and began to express a normal enzyme. This, augmented by weekly injections of ADA, corrected her deficiency. However, the concurrent treatment of ADA injections may impair the success of gene therapy, since transduced cells will have no selective advantage to proliferate if untransduced cells can survive in the presence of the injected ADA.
=== Academic service === Alongside her academic research, Franz is committed to mentoring early career researchers. She was awarded the Duke University Dean's Award for Excellence in Mentoring in 2016. In 2019 Franz was awarded the American Chemical Society Award for Encouraging Women into Careers in the Chemical Sciences. Franz co-edited the American Chemical Society Metals in Medicine Chemical Reviews. Franz was made the chair of the Gordon Research Conference on Metals in Medicine in 2013.
Nanoparticles often develop or receive coatings of other substances, distinct from both the particle's material and of the surrounding medium. Even when only a single molecule thick, these coatings can radically change the particles' properties, such as and chemical reactivity, catalytic activity, and stability in suspension.
== Peptides and proteins == A number of algorithms for estimating isoelectric points of peptides and proteins have been developed. Most of them use Henderson–Hasselbalch equation with different pK values. For instance, within the model proposed by Bjellqvist and co-workers, the pKs were determined between closely related immobilines by focusing the same sample in overlapping pH gradients. Some improvements in the methodology (especially in the determination of the pK values for modified amino acids) have been also proposed. More advanced methods take into account the effect of adjacent amino acids ±3 residues away from a charged aspartic or glutamic acid, the effects on free C terminus, as well as they apply a correction term to the corresponding pK values using genetic algorithm. Other recent approaches are based on a support vector machine algorithm and pKa optimization against experimentally known protein/peptide isoelectric points. Moreover, experimentally measured isoelectric point of proteins were aggregated into the databases. Recently, a database of isoelectric points for all proteins predicted using most of the available methods had been also developed. In practice, a protein with an excess of basic aminoacids (arginine, lysine and/or histidine) will bear an isoelectric point roughly greater than 7 (basic), while a protein with an excess of acidic aminoacids (aspartic acid and/or glutamic acid) will often have an isoelectric point lower than 7 (acidic).
=== Special Counsel to Buddy Roemer === In 1988, Kennedy became special counsel to Governor Buddy Roemer. In 1991, he was also appointed secretary to the governor's cabinet and served in both posts until 1992. Roemer tasked Kennedy with helping him pass two key priorities: tort and campaign finance reforms. Roemer instructed Kennedy to draft the Louisiana Products Liability Act, a bill that aimed to set forth four clear legal theories by which manufacturers could be held liable for damage their products caused. The new code also clarified what counted as "unreasonably dangerous" to help make potential sources of liability more predictable to both businesses and buyers with claims. Roemer then tasked Kennedy with building support for passing the legislation. As part of his advocacy, Kennedy published a law review article titled "A Primer on the Louisiana Products Liability Act". He argued that the Products Liability Act would "bring added clarity, precision and certainty to Louisiana's products liability doctrine" and "strike an equitable balance between the right of a claimant who is injured in a product-related accident to just compensation and the right of the product's manufacturer to be judged fairly." Kennedy also delivered public testimony before the Louisiana House Committee on Civil Law and Procedure in support of the bill, saying that the bill "provides for a state-of-the-art defense for manufacturers." The Louisiana legislature enacted the Louisiana Products Liability Act in 1988.
Sources: en.wikipedia.org
==== All-Russian Cossack Society ==== The All-Russian Cossack Society (Russian: Всероссийское казачье общество) is responsible for the coordination of the activities of all 11 registered Cossack hosts, particularly in the spheres of patriotic education and the continuity of historical Cossack customs and traditions. Both registered and non-registered Cossack organizations can be part of the society. On 4 November 2019, Russian President Vladimir Putin appointed Kuban Vice Governor and Kuban Cossack Host Ataman Nikolai Doluda as Ataman of the All-Russia Cossack Society. Cossack General Doluda was appointed two years after the atamans and the Cossacks created it in October 2017. The idea was first proposed in 1994. On 27 November 2018, delegates of the Constitutive Assembly voted for the establishment of the society and adopted its official statute. Doluda was then nominated for head of the society, in which he was backed by the Presidential Council on Cossack Affairs.
== History == The first recognized description of RA in modern medicine was in 1800 by the French physician Augustin Jacob Landré-Beauvais (1772–1840) who was based in the famed Salpêtrière Hospital in Paris. The name "rheumatoid arthritis" itself was coined in 1859 by British rheumatologist Alfred Baring Garrod. The art of Peter Paul Rubens may depict the effects of RA. In his later paintings, his rendered hands show, in the opinion of some physicians, increasing deformity consistent with the symptoms of the disease. RA appears to some to have been depicted in 16th-century paintings. However, it is generally recognized in art historical circles that the painting of hands in the 16th and 17th century followed certain stylized conventions, most clearly seen in the Mannerist movement. It was conventional, for instance, to show the upheld right hand of Christ in what now appears a deformed posture. These conventions are easily misinterpreted as portrayals of disease. Historic (though not necessarily effective) treatments for RA have also included: rest, ice, compression and elevation, apple diet, nutmeg, some light exercise every now and then, nettles, bee venom, copper bracelets, rhubarb diet, extractions of teeth, fasting, honey, vitamins, insulin, magnets, and electroconvulsive therapy (ECT).
Venom evolved just once among all Toxicofera about 170 million years ago, and then diversified into the huge venom diversity seen today. The original toxicoferan venom was a very simple set of proteins that were assembled in a pair of glands. Subsequently, this set of proteins evolved independently in the various lineages of toxicoferans, including Serpentes, Anguimorpha, and Iguania. Several snake lineages have since lost the ability to produce venom, often due to a change in diet or a change in predatory tactics. In addition to this, venom strength and composition has changed due to changes in the prey of certain snake species. For example, the venom of the marbled sea snake (Aipysurus eydouxii) became significantly less toxic after the diet of this species changed from fish to strictly fish eggs. The evolution of venom is thought to be responsible for the enormous expansion of snakes across the globe. The mechanism of evolution in most cases has been gene duplication in tissues unrelated to the venom. Pre-existing salivary proteins are the likely ancestors of most venom toxin genes. Expression of the new protein in the venom gland followed duplication. Then proceeded natural selection for adaptive traits following the birth-and-death model, where duplication is followed by functional diversification, resulting in the creation of structurally related proteins that have slightly different functions.
An isothermal titration calorimeter is composed of two identical cells made of a highly efficient thermally conducting and chemically inert material such as Hastelloy alloy or gold, surrounded by an adiabatic jacket. In this setup, one of the cells, the sample cell, holds the solution of one reactant, and the other cell, the reference cell, is filled with either a buffer or water. The second reactant, which has a higher concentration than the first, is placed in a syringe and gradually injected into the sample cell in small aliquots throughout the titration process. This process is semi-automated and the sensitive thermopile/thermocouple circuits are used to detect temperature differences between the reference cell (filled with buffer or water) and the sample cell containing the macromolecule. Prior to addition of ligand, a constant power (<1 mW) is applied to the reference cell. This directs a feedback circuit, activating a heater located on the sample cell. During the experiment, ligand is titrated into the sample cell in precisely known aliquots, causing heat to be either taken up or evolved (depending on the nature of the reaction). Measurements consist of the time-dependent input of power required to maintain equal temperatures between the sample and reference cells.
==== Europe ==== In 1998, Starbucks entered the United Kingdom market with the US$83 million acquisition of the then 56-outlet, UK-based Seattle Coffee Company, re-branding all those stores as Starbucks. In October 2002, Starbucks established a coffee trading company in Lausanne, Switzerland, to handle purchases of green coffee. All other coffee-related business continued to be managed from Seattle. In September 2007, the company opened its first store in Russia, ten years after first registering a trademark there. After the Russian invasion of Ukraine, on May 21, 2022, Starbucks announced closure of all outlets in Russia, and in July it was revealed that a local restaurant manager, Anton Pinsky, is going to acquire Starbucks' Russian operating company OOO Starbucks and all its 130 stores. In 2008, Starbucks opened in Belgium, Bulgaria, the Czech Republic, and Portugal.
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.
Most lyophilized products are stored in sealed containers at controlled temperature and humidity. Some require refrigeration, while others are stable at room temperature. Protection from light and moisture is often necessary.