If you have been reading about Container closure 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 2026-02-06. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Misconceptions about lyophilization include the idea that dried products are indefinitely stable or that vacuum sealing eliminates all degradation. Chemical reactions can continue in the solid state, and some proteins lose activity even at low moisture. Another misconception is that any freeze-dryer cycle can be scaled by time alone; heat and mass transfer differ with equipment and load. Open questions remain about predicting long-term stability from short accelerated studies, particularly for amorphous formulations. Real-time stability data remain the standard for shelf-life assignment.
After lyophilization, the dried product is often sealed under vacuum or an inert gas to limit moisture and oxygen exposure. Vials, stoppers, and seals must maintain their barrier throughout shelf life. Storage temperature depends on product sensitivity: some cakes tolerate controlled room temperature, while labile biologics require refrigeration. Humidity is a critical variable because dried cakes are hygroscopic and can absorb water when exposed to air. Handling procedures therefore limit open-vial time and use desiccated environments for sampling.
| 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. |
The process relies on the phase diagram of water, where the triple point marks the conditions at which ice, liquid water, and vapor coexist. By maintaining pressure below this point, typically around 0.01 to 0.1 millibar, sublimation becomes the dominant mechanism. Formulations often include excipients such as sugars or polymers that act as lyoprotectants and bulking agents. These additives help preserve the structure of the active ingredient and prevent collapse during drying. The choice of excipient and freezing rate influences the final cake morphology and stability.
Industries use lyophilization for pharmaceuticals, biological products, and food preservation. In the pharmaceutical sector, it extends the shelf life of injectable drugs, vaccines, and proteins that are unstable in aqueous solution. Food manufacturers apply freeze-drying to coffee, fruits, and ready meals to retain flavor and texture. The process is energy-intensive and requires specialized equipment, which limits its use to high-value products. Ongoing research examines how formulation and process parameters affect the quality of the final dried product.
Lyophilization, also known as freeze-drying, is a process that removes water from a material by freezing it and then reducing pressure to allow ice to sublimate directly into vapor. The method begins with a freezing step that solidifies the water content. Next, primary drying lowers the pressure below the triple point of water, enabling sublimation without passing through a liquid phase. A final secondary drying step removes bound water through desorption. This sequence produces a dry, porous cake that can be reconstituted later.
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.
Freeze-drying is used for materials whose activity or structure depends on low temperature and low water content. Examples include certain biologics, diagnostic reagents, starter cultures, coffee, and porous inorganic precursors. The dried product forms a cake whose porosity aids rapid wetting and dissolution. Main drawbacks are high energy use, long cycle times, and sensitivity to formulation and equipment variation. Questions remain about how freezing rates and ice morphology affect batch uniformity, especially when moving from laboratory to production scale.
Lyophilization, also called freeze-drying, is a dehydration process in which a solvent, usually water, is frozen and then removed by sublimation under reduced pressure. The method preserves heat-sensitive materials that would degrade in conventional drying. Large-scale use grew during the mid-twentieth century for blood plasma and antibiotics, and it later expanded to vaccines, enzymes, foods, and advanced materials. The process produces a dry, porous solid that usually reconstitutes rapidly. It is distinct from simple evaporation because the solvent bypasses the liquid phase during primary removal.
Stability programs monitor lyophilized products under defined temperature and humidity conditions over time. Real-time studies at recommended storage conditions are the reference, while accelerated studies provide early signals of degradation pathways. Because a dry cake can still undergo oxidation, hydrolysis, or aggregation, stability depends on residual moisture, excipients, and container headspace. Open questions include how best to predict long-term stability from short accelerated runs and how vial-to-vial variability affects shelf life. Current guidance treats these predictions as product-specific rather than universally generalizable.
Freeze-dried materials are hygroscopic to varying degrees and can take up moisture after drying. Storage therefore often uses sealed glass vials, rubber stoppers, and crimp seals to limit contact with ambient humidity. A desiccant may be included for moisture-sensitive products, although it is not universal. Controlled room temperature is sufficient for many lyophilizates, while others require refrigeration or freezing. Moisture ingress remains a primary cause of cake collapse, chemical degradation, and loss of reconstitution performance.
Quality assessment of a lyophilized product includes cake appearance, residual moisture, reconstitution time, and container closure integrity. A uniform, porous cake suggests that freezing and drying stayed within the formulation's design space. Cracks, shrinkage, meltback, or a glassy film can indicate thermal abuse or a formulation problem. Analysts also test for subvisible particles and sterility when the product requires those specifications. Visual inspection alone cannot confirm biological activity or chemical stability, so it is combined with analytical methods.
SSRIs are structurally diverse with clear variations in their pharmacodynamic and pharmacokinetic profiles, which leads to differences among them in their half-lifes, clinical activity, adverse effects and drug interactions, which explains the differences in their efficacy and tolerability among patients. However, all SSRIs are clinically equal when it comes to their efficacy over time. Table 2 Comparison of the chemical properties of SSRI drugs
== Medical uses == Oveporexton is indicated for the treatment of narcolepsy type 1 (narcolepsy with cataplexy) in adults. Narcolepsy type 1 is a rare, lifelong neuropsychiatric sleep disorder. It is caused by the loss of brain cells that produce orexin, a chemical messenger that regulates wakefulness, sleep, and muscle tone. Without orexin, the brain struggles to maintain alertness or to control the boundary between sleep and waking. The result is a cluster of disabling symptoms, including excessive daytime sleepiness, cataplexy (sudden muscle weakness triggered by strong emotions such as laughter), sleep paralysis, hallucinations at the edge of sleep or waking, and disrupted nighttime sleep. The effectiveness and safety of oveporexton were evaluated in two randomized, double-blind, placebo-controlled 12-week studies enrolling 273 adults with narcolepsy type 1. Across both studies, participants taking oveporexton 2 mg showed improvements in their ability to stay awake during the day compared with those receiving placebo. Participants also reported substantially less daytime sleepiness, a significant reduction in cataplexy episodes, and meaningful improvement across the full spectrum of narcolepsy symptoms, including sleep paralysis, hallucinations, and disrupted nighttime sleep.
=== Basal metabolic rate === Basal metabolic rate (BMR) is one of the main components of a person's daily energy expenditure. It is defined as the amount of energy that is expended during a given amount of time by a person at rest. This energy at rest is used to pump blood throughout the body, maintain proper brain function, break down toxins, and ensure other bodily functions. Technically speaking, BMR is the energy the body expends during the following specific conditions: immediately after waking up, while in a resting state, and after fasting for 12–14 hours. Sometimes the term Resting Metabolic Rate (RMR) is used in place of BMR, but RMR is not solely measured under the previously listed stringent conditions and it is about 10% more than BMR. The BMR is directly proportional to a person's lean body mass. In other words, the more lean body mass a person has, the higher their BMR. BMR is also affected by acute illnesses and increases with burns, fractures, infections, fevers, etc. It can be measured via direct and indirect calorimetry. However, it is also possible to approximately estimate BMR using several equations that factor in a person's age, sex, height, and weight. Some of the most popular and accurate equations used to calculate BMR are the original Harris-Benedict equations, the revised Harris-Benedict equations, and the Mifflin St. Jeor equation. The original Harris-Benedict Equations are as follows:
A detergent such as sodium dodecyl sulfate (SDS) can be used to dissolve cell membranes and keep membrane proteins in solution during purification; however, because SDS causes denaturation, milder detergents such as Triton X-100 or CHAPS can be used to retain the protein's native conformation during complete purification.
To reduce radiation exposure, the American Society of Nuclear Cardiology (ASNC) issued dosage recommendations in 2010. The effective dose is 2.4 mSv for 13N-ammonia, 2.5 mSv for 15O-water, 7 mSv for 18F-fluorodeoxyglucose, and 13.5 mSv for 82Rb-rubidium chloride. Compliance with these recommendations is expected to reduce the average radiation exposure to = 9 mSv. The Ordinance on Radioactive Drugs or Drugs Treated with Ionizing Radiation § 2 AMRadV (in German) regulates the approval procedures for the marketability of radioactive drugs.
Sources: en.wikipedia.org
=== Cancer resistance === Dermal macrophages can adjust their phenotypes to increase or suppress skin inflammation by different gene profiles, which can slow down the development of certain cancers. For instance, they can suppress the development of basal cell carcinoma. Basal cell carcinoma is induced by mutations in PTCH1, a tumour-suppressor protein, leading to uncontrollable cell growth. In rodents, there is increased growth of basal cell carcinoma and loss of normal cells without the presence of macrophages. Therefore, dermal macrophages are associated with cancer defence.
FDA states that 798 of the 1,130 MDRs for BIA-ALCL involved textured breast implants, 37 MDRs involved smooth-surfaced implants, and 295 MDRs did not specify whether the implants were textured or smooth. In some cases, the women who developed BIA-ALCL after smooth breast implants had textured expanders prior to their implants. Most patients had BIA-ALCL affect only one breast with only 8 patients diagnosed with bilateral BIA-ALCL. The most common reported symptom of BIA-ALCL according to the FDA was seroma, followed by breast swelling and pain, capsular contracture, and peri-implant mass or lump. Furthermore, 84 percent of the reported implants were made by Allergan, the largest breast implant manufacturer at the time. A study conducted at Memorial Sloan Kettering cancer center of women undergoing prophylactic mastectomies indicated that 1 in 355 women were subsequently diagnosed with BIA-ALCL. Almost all those women had Allergan biocell implants and expanders. These reports strongly suggest that BIA-ALCL develops primarily in patients with textured implants or expanders. In all cases, however, many researchers suspect that BIA-ALCL is an under-recognized, misdiagnosed, and under-reported complication of breast implants. The ASPS and the Plastic Surgery Foundation (PSF) have partnered with the FDA to study this condition and in doing so created the Patient Registry and Outcomes for Breast Implants and Anaplastic Large Cell Lymphoma Etiology and Epidemiology (PROFILE).
Some say we should hold elections tomorrow, those have no chances of being free and fair." and added "Ultimately what the long term political leadership is going be, it’s going to be up to Venezuelans." During a conference in Saint Kitts and Nevis with other Caribbean nations on 25 February, United States Secretary of State Marco Rubio said that the US recognizes the need for fair, democratic elections in Venezuela, saying "We do believe that a prosperous, free Venezuela who’s governed by a legitimate government who has the interests of their people in mind could also be an extraordinary partner and asset to many of the countries represented here today." Juan Pablo Guanipa, ally of Machado and political prisoner released during a mass political prisoner release in Venezuela in 2026, said for Spanish newspaper El País, that elections are under way and that Chavismo has lost its ability to impose conditions.
== Adulterant in illegal drugs == In the body, levamisole is converted into aminorex, a substance with amphetamine-like stimulant effects and a long duration of action. Beginning in early 2003, South American cartels started adding levamisole to bulk cocaine before shipping it to the United States (Valentino and Fuentecilla 2005). Levamisole has increasingly been used as a cutting agent in cocaine sold around the globe with the highest incidence being in the United States. In 2008–2009, levamisole was found in 69% of cocaine samples seized by the Drug Enforcement Administration (DEA). By April 2011, the DEA reported the adulterant was found in 82% of seizures. By October 2017, this figure had risen further, with the DEA reporting that 87% of seized and analyzed cocaine bricks in the United States contained levamisole, making it the most common adulterant in cocaine at that time. Levamisole adds bulk and weight to powdered cocaine (whereas other adulterants produce smaller "rocks" of cocaine) and makes the drug appear purer. In a series of investigative articles for The Stranger, Brendan Kiley details other rationales for levamisole's rise as an adulterant: possible stimulant effects, a similar appearance to cocaine, and an ability to pass street purity tests. Levamisole suppresses the production of white blood cells, resulting in neutropenia and agranulocytosis. With the increasing use of levamisole as an adulterant, a number of these complications have been reported among cocaine users.
Sources: en.wikipedia.org
=== Expansion and growth === When defined as "organizations with at least three state parties, a permanent headquarters or secretariat, as well as regular meetings and budgets", the number of IGOs in the world increased from about 60 in 1940 to about 350 in 1980, after which it has remained roughly constant.
Halliwell was awarded the Public Administration Medal (Silver) in 2010 by the President of Singapore for contributions to Singapore and awarded the President's Science and Technology Medal (2013) by the President of Singapore "for distinguished sustained and exceptional contributions to Singapore's Science and Engineering landscape". Halliwell was conferred the Outstanding Service Award at the NUS University Awards on 8 September 2023. In 2008, Halliwell was awarded the "Lifetime Achievement Award" by the Society for Free Radical Biology and Medicine in the US for overall sustained excellence in the field. He was described as a "Research Pioneer" by the journal Antioxidants & Redox Signaling in 2011. Same year, he was also awarded the Ken Bowman Research Award for outstanding achievements in the field of cardiovascular research from the Institute of Cardiovascular Sciences (Canada) and NUS University Award – Outstanding Researcher Award. He was elected a fellow of the American Association for the Advancement of Science in 2012. Halliwell was awarded a Doctor of Science honoris causa by King's College London in 2018. He was again identified as a "Highly Cited Scientist" for cross-disciplinary work by Clarivate Analytics in 2018. He was honoured as a Citation Laureate (2021) for "pioneering research in free-radical chemistry including the role of free radicals and antioxidants in human disease".
Pynegabine (developmental code name HN37) is a Kv7.2 and Kv7.3 potassium channel opener which is under development for the treatment of epilepsy in China. The drug is an analogue of flupirtine and retigabine (ezogabine). However, it shows 55-fold greater potency in activating Kv7.2 channels and 127-fold greater potency in activating Kv7.3 channels compared to retigabine in vitro. In addition, it shows improved chemical or metabolic stability compared to retigabine and in relation to this may have reduced toxicity in comparison. The drug is under development by the Shanghai Institute of Materia Medica and Hainan Haiyao. As of 2026, it is in phase 2 clinical trials for epilepsy.
Nelson turned Fruton on to biochemistry. He received his degree in chemistry in 1931, and entered graduate school in the Department of Biological Chemistry in the Columbia College of Physicians and Surgeons, working under Hans Thacher Clarke. Fruton's PhD work focused on "the lability of cystine in alkali", although he developed a broad interest in the range of biochemistry-related research being pursued at the College of Physicians and Surgeons. During graduate school Fruton also became active politically, opposing fascism, militarism and anti-Semitism. In 1933 he met Sophia "Topsy" Simmonds, whom he married in 1936. Upon completing his PhD in May 1934, Fruton became a research assistant to Max Bergmann at the Rockefeller Institute for Medical Research.
Hong Kong is a major stop-over for foreign fish maw to be smuggled into mainland China, in order to circumvent food-safety import laws and import duties to mainland China. In Kenya, fish maw fished from Lake Victoria is smuggled through to Uganda and Tanzania to avoid export duties to China, as China charges a GDP-dependent duty on imports.
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.
No. Freeze-drying removes water but does not reliably kill microorganisms. Sterile lyophilized products are typically prepared aseptically before freezing or are sterilized by a validated method. Microbial control depends on the entire manufacturing process.