stability study raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2025-11-08 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Residual moisture | 0.5-3% w/w | Typical range for many biopharmaceuticals |
| Typical storage temperature | 2-8 °C | Some products require -20 °C or lower |
| Reconstitution time | Seconds to several minutes | Depends on cake porosity and diluent |
| Common moisture method | Karl Fischer titration | Measures water content in the solid |
| Container closure | Stoppered vial with seal | Protects against moisture and oxygen ingress |
In addition, legal counsel to the president Harriet Miers and deputy chief of staff to the president Joshua Bolten were both found in contempt of Congress. In 2010, the Justice Department investigator concluded that though political considerations did play a part in as many as four of the attorney firings, the firings were "inappropriately political" but not criminal. According to the prosecutors, there was insufficient evidence to pursue prosecution for any criminal offense.
In this scenario, fusion proteins containing GFP are introduced indirectly, using RNA of the construct, or directly, with the tagged protein itself. This method is useful for studying structural and functional characteristics of the tagged protein on a macromolecular or single-molecule scale with fluorescence microscopy. The Vertico SMI microscope using the SPDM Phymod technology uses the so-called "reversible photobleaching" effect of fluorescent dyes like GFP and its derivatives to localize them as single molecules in an optical resolution of 10 nm. This can also be performed as a co-localization of two GFP derivatives (2CLM). Another powerful use of GFP is to express the protein in small sets of specific cells. This allows researchers to optically detect specific types of cells in vitro (in a dish), or even in vivo (in the living organism). GFP is considered to be a reliable reporter of gene expression in eukaryotic cells when the fluorescence is measured by flow cytometry. Genetically combining several spectral variants of GFP is a useful trick for the analysis of brain circuitry (Brainbow). Other interesting uses of fluorescent proteins in the literature include using FPs as sensors of neuron membrane potential, tracking of AMPA receptors on cell membranes, viral entry and the infection of individual influenza viruses and lentiviral viruses, etc. It has also been found that new lines of transgenic GFP rats can be relevant for gene therapy as well as regenerative medicine.
== Effect of pressure == At temperatures below 300 °C water is fairly incompressible, which means that pressure has little effect on the physical properties of water, provided it is sufficient to maintain a liquid state. This pressure is given by the saturated vapour pressure, and can be looked up in steam tables, or calculated. As a guide, the saturated vapour pressure at 121 °C is 200 kPa, 150 °C is 470 kPa, and 200 °C is 1550 kPa. The critical point is 21.7 MPa at a temperature of 374 °C, above which water is supercritical rather than superheated. Above about 300 °C, water starts to behave as a near-critical liquid, and physical properties such as density start to change more significantly with pressure. However, higher pressures increase the rate of extractions using superheated water below 300 °C. This could be due to effects on the substrate, particularly plant materials, rather than changing water properties.
The Jalisco New Generation Cartel (Spanish: Cártel de Jalisco Nueva Generación, pronounced [ˈkaɾtel ðe xaˈlisko ˈnweβa xeneɾaˈsjon]), also known as CJNG, is a Mexican criminal syndicate based in Jalisco founded and headed by Nemesio Oseguera Cervantes, commonly known as El Mencho, until he was killed by the Mexican Army in 2026. The cartel has been characterized by extreme violence and public relations campaigns. Though the CJNG is known for diversifying into various criminal rackets, drug trafficking (primarily cocaine and methamphetamine) remains its most profitable activity. The cartel has been noted for cannibalizing victims during the training of newly inducted sicarios or members, as well as using drones and rocket-propelled grenades to attack rival groups. CJNG started in 2009 as a splinter group of the Milenio Cartel, the other being La Resistencia. CJNG defeated La Resistencia and took control of Milenio's smuggling networks. CJNG expanded its operation network from coast to coast in six months, making it one of the criminal groups with the greatest operating capacity by 2012. Following the emergence of the cartel, homicides, kidnappings and discoveries of mass graves spiked in Jalisco. By 2018, the CJNG was believed to have over 100 methamphetamine labs throughout Mexico. Based on average street value, its trade could net upwards of $8 billion for cocaine and $4.6 billion for crystal meth each year.
Sources: en.wikipedia.org
=== Standalone books === Orange Rhymes With Everything (novella) (Morrow) 1998 Hidden River (Scribner) 2005 Fifty Grand (Holt) 2009 Falling Glass (Serpent's Tail) 2011 Deviant (Abrams) 2011 The Sun Is God (Serpent's Tail in the UK/Seventh Street Books in the US) 2014 The Chain (Orion) 2019 The Island (Little, Brown and Company) 2022
=== Atlas Copco (2014-present) === The Atlas Copco Group, a Swedish multinational industrial company, acquires Edwards Vacuum. Edwards purchased Brooks Automation's CTI-Cryogenics and Polycold branded cryopump operations based in Chelmsford and Monterrey for US$675 million in 2018. In 2019, Edwards marked its 100th anniversary. Its new North America Semiconductor Technology Centre in Hillsboro opened in the same year. Edwards joined MIT.nano as a founding member, following its completion in 2018. MIT.nano is a 214,000-square-foot laboratory dedicated to the characterisation and fabrication of nanoscale materials, structures, devices, and processes. In 2020, the company opened a new Service Technology Centre in Dublin. In 2022, Edwards invested in a new facility to manufacture products for the semiconductor industry in Arizona, USA. During the same year, Edwards acquired Ceres Technologies, Inc.. Ceres is a US-based manufacturer and designer of gas and vapour delivery equipment for the semiconductor industry. It also purchased HHV Pumps Pvt Ltd, a designer and manufacturer of vacuum pumps located in Bengalaru, India, for £10.9 million. Atlas Copco also agreed to purchase the assets of Chinese, liquid ring vacuum pump manufacturer Shandong Jinggong Pump Co Ltd, to join the Edwards vacuum pump business.
== Biosynthesis == Biological precursors of most alkaloids are amino acids, such as ornithine, lysine, phenylalanine, tyrosine, tryptophan, histidine, aspartic acid, and anthranilic acid. Nicotinic acid can be synthesized from tryptophan or aspartic acid. Ways of alkaloid biosynthesis are too numerous and cannot be easily classified. However, there are a few typical reactions involved in the biosynthesis of various classes of alkaloids, including synthesis of Schiff bases and Mannich reaction.
Sources: en.wikipedia.org
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.
Most lyophilized products are stored upright at controlled temperatures, often refrigerated or frozen. Protection from moisture and light helps maintain the dried cake.
A diluent is added to the dried cake, which dissolves to form a solution or suspension. Gentle mixing avoids foaming and preserves sensitive molecules.
Lyophilization relies on sublimation, so water moves from solid ice to vapor without becoming liquid. The material is frozen, pressure is reduced, and controlled heat is supplied. Vapor is captured on a cold condenser, leaving a dry porous solid.