If you have been reading about Collapse temperature 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.
Updated 2025-10-04. Numbers and descriptions here follow the published literature rather than marketing material.
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.
The physics of freeze-drying couples heat transfer, mass transfer, and phase change. Heat supplied through the shelf must reach the sublimation front without melting the ice or degrading the product. Water vapor then travels through the already dried layer and leaves the chamber, where low pressure and cold traps keep it from returning. The dried layer acts as a resistance to vapor flow, so drying rate changes as the front recedes. Open questions remain about how pore structure and formulation heterogeneity affect drying uniformity at larger scales.
Lyophilized products are typically stored as sealed solids in vials or syringes. Moisture ingress is a major concern because many dried cakes are hygroscopic and can lose stability when exposed to humid air. Storage temperature depends on the formulation; some products are kept refrigerated, while others are stable at room temperature. Container closure integrity and headspace moisture are often monitored. Light protection may also be required for some photosensitive materials.
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 name | Freeze-drying | Process removes water by sublimation under vacuum. |
| Typical primary drying shelf temperature | -40 C to -10 C | Set below the formulation's collapse temperature. |
| Typical chamber pressure | 0.05-0.3 mbar | Low pressure allows ice to sublime below its triple point. |
| Water content after drying | 0.5-3% by weight | Higher values may reduce storage stability for some materials. |
| Key thermal parameter | Collapse temperature | Measured by freeze-drying microscopy or differential scanning calorimetry. |
== Treatment == NMS is a medical emergency and can lead to death if untreated. The first step is to stop the culprit medication and treat the hyperthermia aggressively, such as with cooling blankets or ice packs to the axillae and groin. Acetaminophen is commonly used as an anti-pyretic. Supportive care in an intensive care unit capable of circulatory and ventilatory support is crucial. In those unable to control their secretions, or who have muscle spams of the respiratory muscles, mechanical ventilation may be needed. The best pharmacological treatment is still unclear. Dantrolene has been used when needed to reduce muscle rigidity, and dopamine pathway medications such as bromocriptine have shown benefit. Dantrolene may act centrally on thermoregulatory pathways to lower the temperature. Dantrolene also inhibits calcium release from the muscle sarcoplasmic reticulum to cause muscle relaxation. Amantadine is another treatment option due to its dopaminergic and anticholinergic effects. Apomorphine may be used however its use is supported by little evidence. Benzodiazepines may be used to control agitation. Highly elevated blood myoglobin levels from muscle breakdown (rhabdomyolysis) can result in kidney damage, therefore aggressive intravenous hydration with diuresis may be required. When recognized early NMS can be successfully managed; however, up to 10% of cases can be fatal. Should the affected person subsequently require an antipsychotic, trialing a low dose of a low-potency atypical antipsychotic is recommended.
The Southwest United States is a significant source of turquoise; Arizona, California (San Bernardino, Imperial, Inyo counties), Colorado (Conejos, El Paso, Lake, Saguache counties), New Mexico (Eddy, Grant, Otero, Santa Fe counties) and Nevada (Clark, Elko, Esmeralda County, Eureka, Lander, Mineral County and Nye counties) are (or were) especially rich. The deposits of California and New Mexico were mined by pre-Columbian Native Americans using stone tools, some local and some from as far away as central Mexico. Cerrillos, New Mexico, is thought to be the location of the oldest mines; prior to the 1920s, the state was the country's largest producer; it is more or less exhausted today. Only one mine in California, located at Apache Canyon, operates at a commercial capacity today. The turquoise occurs as vein or seam fillings, and as compact nuggets; these are mostly small in size. While quite fine material is sometimes found, rivalling Iranian material in both colour and durability, most American turquoise is of a low grade (called "chalk turquoise"); high iron levels mean greens and yellows predominate, and a typically friable consistency in the turquoise's untreated state precludes use in jewelry. Arizona is currently the most important producer of turquoise by value. Several mines exist in the state, two of them famous for their unique colour and quality and considered the best in the industry: the Sleeping Beauty Mine in Globe ceased turquoise mining in August 2012.
== Species distribution == G6PD is widely distributed in many species from bacteria to humans. Multiple sequence alignment of over 100 known G6PDs from different organisms reveal sequence identity ranging from 30% to 94%. Human G6PD has over 30% identity in amino acid sequence to G6PD sequences from other species. Humans also have two isoforms of a single gene coding for G6PD. Moreover, at least 168 disease-causing mutations in this gene have been discovered. These mutations are mainly missense mutations that result in amino acid substitutions, and while some of them result in G6PD deficiency, others do not seem to result in any noticeable functional differences. Some scientists have proposed that some of the genetic variation in human G6PD resulted from generations of adaptation to malarial infection. Other species experience a variation in G6PD as well. In higher plants, several isoforms of G6PDH have been reported, which are localized in the cytosol, the plastidic stroma, and peroxisomes. A modified F420-dependent (as opposed to NADP+-dependent) G6PD is found in Mycobacterium tuberculosis, and is of interest for treating tuberculosis. The bacterial G6PD found in Leuconostoc mesenteroides was shown to be reactive toward 4-hydroxynonenal, in addition to G6P.
Sources: en.wikipedia.org
== General readings == Cross, J.W. (2006). The Charms of Duckweed. Landolt, E. (1986) Biosystematic investigations in the family of duckweeds (Lemnaceae). Vol. 2. The family of Lemnaceae – A monographic study. Part 1 of the monograph: Morphology; karyology; ecology; geographic distribution; systematic position; nomenclature; descriptions. Veröff. Geobot. Inst., Stiftung Rübel, ETH, Zurich.
=== Ligand exchange/functionalization === After initial nanoparticle synthesis, colloidal gold ligands are often exchanged with new ligands designed for specific applications. For example, Au NPs produced via the Turkevich-style (or Citrate Reduction) method are readily reacted via ligand exchange reactions, due to the relatively weak binding between the carboxyl groups and the surfaces of the NPs. This ligand exchange can produce conjugation with a number of biomolecules from DNA to RNA to proteins to polymers (such as PEG) to increase biocompatibility and functionality. For example, ligands have been shown to enhance catalytic activity by mediating interactions between adsorbates and the active gold surfaces for specific oxygenation reactions. Ligand exchange can also be used to promote phase transfer of the colloidal particles. Ligand exchange is also possible with alkane thiol-arrested NPs produced from the Brust-type synthesis method, although higher temperatures are needed to promote the rate of the ligand detachment. An alternative method for further functionalization is achieved through the conjugation of the ligands with other molecules, though this method can cause the colloidal stability of the Au NPs to breakdown.
== Demise == The Arab League – led by Egypt – set up the All-Palestine Government (an Egyptian protectorate) in Gaza on 8 September 1948, while the 1948 Arab–Israeli War was in progress, under the nominal leadership of Amin al-Husayni, which was soon recognized by six of the seven Arab League members, the exception being Transjordan. King Abdullah of Transjordan regarded the attempt to revive al-Husayni's Holy War Army as a challenge to his authority and all armed bodies operating in the areas controlled by the Arab Legion were ordered to disband. Glubb Pasha carried out the order ruthlessly and efficiently. After the war, the Arab Higher Committee was politically irrelevant, and banned from the Jordanian West Bank, as was the All-Palestine Government.
Sources: en.wikipedia.org
Research has shown that a mutation of G—>C in the −6 position of the β-globin gene (β+45; human) disrupted the haematological and biosynthetic phenotype function. This was the first mutation found in the Kozak sequence and showed a 30% decrease in translational efficiency. It was found in a family from the Southeast Italy and they suffered from thalassaemia intermedia. Similar observations were made regarding mutations in the position −5 from the start codon, AUG. Cytosine in this position, as opposed to thymine, showed more efficient translation and increased expression of the platelet adhesion receptor, glycoprotein Ibα in humans. Mutations to the Kozak sequence can also have drastic effects upon human health; in particular, certain forms of congenital heart disease are caused by Kozak sequence mutations in the GATA4 gene's 5' untranslated region. The GATA4 gene is responsible for gene expression in a wide variety of tissues including the heart. When the guanosine at the -6 position in the Kozak sequence of GATA4 is mutated to a cytosine, a reduction in GATA4 protein levels results, which leads to a decrease in the expression of genes regulated by the GATA4 transcription factor and linked to the development of atrial septal defect. The ability of the Kozak sequence to optimize translation can result in novel initiation codons in the typically untranslated region of the 5′ (5′ UTR) end of the mRNA transcript. A G to A mutation was described by Bohlen et al.
== Injectable materials == Many different materials have been used as perianal injectable bulking agents. The ideal injectable or implantable material would be biocompatible, non-migratory, non-allergenic, non-carcinogenic and non-immunogenic (and therefore induce a minimal inflammatory and fibrotic reaction). The material should also be easy to inject. The particles should be greater than 80 μm in diameter in order to prevent migration away from the injection site. On the other hand, materials with particles small enough to be used in small caliber needles may be desirable, in order to leave a smaller needle track, which may reduce the chance of leakage of the material via the needle track. Alternatively, some materials are shape-retaining porous hydrogels with no particles. The ideal material should produce an improvement in continence not only in the short term, but in the long term, and repeated procedures should not be necessary. Technically, most materials are particles suspended in a carrier (excipient) solution, which is usually a biodegradable gel. It is not known which of the available materials is the best.
=== Lungs === Fibrothorax Pulmonary fibrosis Cystic fibrosis Idiopathic pulmonary fibrosis (idiopathic meaning 'of unknown cause') Radiation-induced lung injury (following radiation therapies commonly used to treat cancer)
Sources: en.wikipedia.org
Primary drying removes ice by sublimation at low pressure and low shelf temperature. Secondary drying removes bound water by raising the shelf temperature, often under the same vacuum. The two stages differ in the water state being removed.
Freezing determines ice crystal size, pore structure, and the concentration of solutes in remaining liquid. Faster freezing generally creates smaller ice crystals and a denser dried matrix. These features affect drying rate and reconstitution behavior.
Lyophilization reduces water content but usually leaves a small amount of water in the dried material. Some water remains bound to solids or trapped in the dried matrix. Very low water targets can require extended secondary drying, which may alter product 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.