What are the applications of MD molecular (short-range) stills in the biopharmaceutical industry
MD molecular (short-range) distiller is an efficient and low-temperature separation equipment that utilizes the difference in molecular free path to achieve mixture separation. Its core advantages include operating temperature far below the boiling point of the material (which can be reduced by 30% -50%), high vacuum degree (usually up to 0.001-1Pa), short heating time (only a few seconds to tens
MD molecular (short-range) distiller is an efficient and low-temperature separation equipment that utilizes the difference in molecular free path to achieve mixture separation. Its core advantages include operating temperature far below the boiling point of the material (which can be reduced by 30% -50%), high vacuum degree (usually up to 0.001-1Pa), short heating time (only a few seconds to tens of seconds), and the ability to retain the activity and purity of heat sensitive, easily oxidizable, and high-value substances. This characteristic makes it a key separation and purification equipment in the biopharmaceutical industry, mainly used in three core scenarios: extraction and purification of medicinal ingredients, removal of harmful substances, and refinement of formulation excipients. The specific applications are as follows:
1、 Extraction and purification of medicinal active ingredients (API)
A large number of medicinal ingredients in biopharmaceuticals, such as natural product extracts and microbial metabolites, are heat sensitive. Traditional distillation, such as vacuum distillation, can easily lead to their decomposition and denaturation, while molecular distillation can achieve efficient separation at low temperatures and is the core technology for purifying such ingredients.
1. Separation of active ingredients in natural medicines
When extracting high-purity medicinal ingredients from plant and animal derived raw materials, molecular distillation can solve the contradiction between "heat sensitive ingredient retention" and "high-purity separation".
Example 1: Purification of active ingredients in traditional Chinese medicine (such as ginsenosides, paclitaxel, artemisinin). Taking artemisinin as an example, its crude extract contains impurities (such as chlorophyll and other terpenes), and artemisinin is easily decomposed by heat (traditional distillation temperature>120 ℃ will damage the structure). Molecular distillation can separate artemisinin from impurities at a vacuum degree of 0.1Pa and a temperature of 60-80 ℃, with a purity of over 99%, while retaining its anti malaria activity.
Example 2: Purification of animal derived drugs (such as EPA/DHA in fish oil, lecithin in egg yolk). In the preparation of "medicinal grade phospholipids", crude phospholipids contain impurities such as triglycerides and fatty acids. Molecular distillation can remove impurities at low temperatures (50-70 ℃) to obtain medicinal phospholipids with a purity of ≥ 98%, avoiding the oxidation and denaturation of phospholipids caused by traditional high-temperature processes (which affects their safety as injection excipients).
2. Refinement of microbial metabolites
In biopharmaceuticals, antibiotics, vitamins, etc. are often produced through microbial fermentation. After initial extraction, the fermentation broth still contains impurities (such as bacterial residue and by-products), and molecular distillation can be used for subsequent refinement.
Example: Purification of Vitamin E (tocopherol). The crude vitamin E produced by microbial fermentation method contains impurities such as sterols and fatty acid methyl esters, and vitamin E is prone to oxidation and failure at high temperatures. Molecular distillation can achieve the separation of vitamin E from impurities at a vacuum degree of 0.01Pa and a temperature of 120-140 ℃ (much lower than its conventional boiling point of 284 ℃), with a purity of over 95%, meeting pharmaceutical grade standards (used for antioxidants or auxiliary drugs).
2、 Purification and detoxification of medicinal raw materials/excipients
Biopharmaceuticals require high purity of raw materials/excipients, and strict control of the content of "low molecular impurities and harmful substances (such as heavy metals and solvent residues)" is necessary. Molecular distillation can remove these impurities in a targeted manner to ensure drug safety.
1. Removal of solvent residues and volatile impurities
Medicinal raw materials (such as API intermediates) often use organic solvents (such as methanol, dichloromethane, ethyl acetate) in the synthesis or extraction process. Traditional drying or vacuum distillation is difficult to remove trace solvents (especially high boiling point solvents), while molecular distillation can efficiently remove them through "low temperature+high vacuum".
Example: Solvent removal of pharmaceutical grade API intermediates. A certain antibiotic intermediate (such as amoxicillin precursor) has residual ethyl acetate (boiling point 77 ℃, but conventional vacuum distillation requires above 80 ℃ to remove, which can easily lead to intermediate decomposition) after synthesis. Molecular distillation can reduce the solvent residue to ≤ 10ppm under a vacuum degree of 0.1Pa and a temperature of 40-50 ℃ (in accordance with the pharmaceutical grade standards of the Chinese Pharmacopoeia), while avoiding structural damage to the intermediate.
2. Separation of low molecular impurities and harmful substances
Some medicinal raw materials contain low molecular weight polymers, heavy metal complexes (such as lead and mercury), or pyrolysis products. Molecular distillation can utilize the "molecular free path difference" (low molecular impurities have long free paths and are easily collected by condensation) to remove them.
Example: Refinement of pharmaceutical grade polyethylene glycol (PEG). PEG, as an injection excipient (such as co solvent, ointment matrix), needs to control the content of low molecular weight PEG (such as PEG200/400) to avoid triggering allergic reactions. Crude PEG contains low molecular weight fragments, and molecular distillation can remove low molecular impurities at a vacuum degree of 0.001Pa and a temperature of 180-200 ℃ (much lower than the decomposition temperature of PEG at 250 ℃), making the molecular weight distribution of PEG more uniform and meeting pharmaceutical grade requirements.
3、 Preparation of "Special Preparations" for Biopharmaceuticals
In the production of some high value-added biologics, such as liposomes, microspheres, and injectable emulsions, molecular distillation can be used for refining key excipients or processing formulations to ensure their stability and bioavailability.
1. Purification of excipients for liposome formulations
The core excipient of liposomes (used for targeted drug delivery, such as anticancer drug liposomes) is "phospholipids" (such as soybean phospholipids and egg yolk phospholipids). The free fatty acids and cholesterol impurities contained in crude phospholipids can damage the structure of liposomes, leading to drug leakage. Molecular distillation can remove these impurities at low temperatures (60-80 ℃) to obtain high-purity phospholipids (free fatty acid content ≤ 0.5%), ensuring the encapsulation efficiency (≥ 90%) and stability (storage period>12 months) of liposomes.
2. Auxiliary treatment of "antipyretic" emulsion for injection
Pyrogens (such as bacterial endotoxins) are a key safety hazard for injections. Traditional methods of removing pyrogens (such as ultrafiltration and activated carbon adsorption) may affect drug activity, while molecular distillation can assist in removing pyrogens through "selective separation" (the free path of pyrogen molecules is significantly different from that of drug molecules).
Example: Refinement of Fat Emulsion Injection. The raw material of fat emulsion (used for parenteral nutrition) is vegetable oil (such as soybean oil). If it contains trace amounts of pyrogen, it may cause fever reactions in patients. Molecular distillation can remove pyrogen and low molecular impurities from vegetable oil at a vacuum degree of 0.01Pa and a temperature of 100-120 ℃, ensuring that the fat emulsion injection meets the pyrogen test standards of the Chinese Pharmacopoeia (bacterial endotoxin<0.5EU/mL).
4、 Summary of application advantages: Why does the biopharmaceutical industry prefer molecular distillation?
Compared to traditional separation techniques such as vacuum distillation, extraction, and chromatography, the core value of MD molecular stills in biopharmaceuticals lies in:
1. Protecting the activity of thermosensitive drugs: Low temperature operation avoids the decomposition and denaturation of APIs or excipients due to high temperature, especially suitable for natural drugs and protein drugs (some proteins become inactive above 60 ℃).
2. High purity and high yield: The separation efficiency is high under high vacuum degree, and the purity of the target component can reach 95% -99.9%, with a yield usually greater than 90% (traditional process yields are mostly 70% -85%), reducing the waste of high-value raw materials.
3. Complies with GMP hygiene requirements: The equipment material is mostly 316L stainless steel, with smooth inner walls and no dead corners, easy to clean and sterilize (CIP/SIP online cleaning and sterilization can be carried out), avoiding cross contamination and meeting GMP standards for biopharmaceuticals.
4. Solvent free secondary pollution: The separation process does not require the addition of auxiliary reagents such as extractants and adsorbents, avoiding solvent residue or reagent pollution from the source and ensuring drug safety.