On the market today, there are many herbal preparations and the trend of using drugs derived from medicinal herbs is increasing. Therefore, the pharmaceutical market is increasingly active, but the quality of medicinal herbs is a burning problem for the whole community. Rude testing methods such as based on shape, color, etc. can lead to erroneous conclusions. Many modern methods have been applied to test and control the quality of medicinal herbs and preparations, in which the first requirement is to have a standard substance. However, in fact, our country still faces difficulties in analysis and testing due to the lack of necessary standards.
So what is the standard?
Standard substances or reference standards are substances necessary to evaluate raw materials, semi-finished products, finished products, etc., according to defined procedures to ensure accurate analytical results. authentic, reliable.
There are many different standards on the market today.
- Pharmacopoeia Standard: A primary standard established on the recommendation of a technical expert committee for pharmaceutical preparations, used primarily in chemical and physical testing and analysis. described in detail in pharmacopoeias or draft monographs, can be used to calibrate secondary standards.
- Primary Standard: Standard substances that are fully validated and widely accepted, of suitable quality under specified conditions, and of acceptable value without having to be compared with other standards. other.
- Pharmacopoeia standard substances include: international pharmacopoeia standards, European pharmacopoeia standard, British pharmacopoeia standard, American pharmacopoeial standard, Japanese pharmacopoeia standard… Vietnam's pharmacopoeia mentions reference substances (Section 2.5, Appendix). Appendix 2, page PL-105), which contains the official regulations that the distributors are the Central Institute for Drug Testing and the City Drug Testing Institute. HCM.
- Working standards or secondary standards: biological or chemical standards established on raw materials that have been standardized against primary standards or by analytical precision. Highly accurate to widely available to drug laboratories, used for qualitative, quantitative, potency assessment, purity determination of drugs, raw materials and finished products. A secondary standard is a substance whose purity and quality have been established by comparison with a primary standard that is used as a reference standard for routine laboratory analysis.
- Baseline or Manufacturer Standard: Substances produced and established by the establishment or manufacturer according to the establishment's procedures and criteria. The basic standards are purified, fully described and clearly defined structure (IR, UV, MNR, MS...), often used for new chemical substances (New Chemical Entity - NCE) with no expertise essay.
Requirements for standards
Whether it is a regional standard, a national standard or a working standard, the following general principles of establishment, storage and distribution must be followed:
- Raw materials used to establish standards must be of high purity (for pharmaceutical chemical compounds > 95%), selected from batches of high quality, homogenous drug production materials and supplied supplied from reliable sources (original manufacturers).
- The assessment of the suitability of a material intended to be a benchmark should be carried out with great care, taking into account all data obtained from tests, and a variety of analytical methods should be used to evaluate the quality of the material. comparative price.
- Reputable standards manufacturers often develop a specific, rigorous process to validate their standards.
Scope of use of standards
Reference standards are used in the following ranges:
- Method validation.
- Determine the method (method veryfication).
- Determination of measurement uncertainty
- Calibration.
- Quality control
- Quality assurance
- Research (especially in pharmaceutical research to identify substances, monitor drug stability ...)
In fact, standards are used a lot in product quality testing (drugs, functional foods, food, goods, etc.)
In the field of testing, reference standards are often used in tests:
- Qualitative by instrumental analysis methods (infrared, ultraviolet ...).
- Impurity limit test (SKLM, GC, HPLC...).
- Quantification by instrumental methods (UV, HPLC).
- Quantification by biological methods (e.g. antibiotic activity test).
- Used in drug tests (e.g. solubility testing).
- Tests using special or rare reagents (e.g. enzyme activity tests).
- Other trials specified in the pharmacopoeia monographs
The role of ISO in setting standards
ISO stands for International Organization for Standardization (International Organization for Standardization), established in 1946 and officially operating on February 23, 1947. Vietnam officially joined in 1977 and is the 71st member of ISO.
To build the process of setting up and certifying standards, standard substance preparation units mainly rely on three sets of ISO Guides 31, 34 and 35 as a basis:
- ISO Guide 31 (2000) provides the necessary instructions to help standard manufacturers prepare clear, concise certificates of analysis in accordance with international standards.
- ISO Guide 34 (2000) sets out the requirements that manufacturers need to meet, and provides guidance on how to meet these requirements. In general, this guide provides models for homogeneity testing, stability, and content determination of the test material.
- ISO Guide 35 (2006) is seen as an application of the Guide to the Expression of Uncertainty in Measurement (GUM). This ISO Guide provides detailed guidance on how to determine measurement uncertainty and how to assess batch homogeneity and stability during standardization.
Inventions on standard substances have developed strongly in recent times
1967: The first invention relates to a standard substance in serological testing.
In recent years, in Vietnam, many scientists have focused on the preparation of standard substances, for example:
- Lu Thi Kim Chi, Vu Thi Ngoc Dinh, Nguyen Ngoc Vinh (2017), Isolation and establishment of vitexin standards from passionflower (Passiflora foetida Linn.), Journal of Pharmacology, 57(3).
- Tran Viet Hung, Pham Van Kien, Bui Quoc Thai, Doan Cao Son, Nguyen Tien Dat, Bui Hong Cuong (2017), Research on extracting, isolating and purifying monotropein from Ba Kich as standard setting materials, Journal pharmacology, 57 (5).
- Nguyen Thi Anh Nguyet, Le Phan Kim Trang, Pham Dong Phuong (2016), Isolation and establishment of chlorogenic acid standards, Journal of Pharmacology, 56 (11).
- Hoang Thi Tuyet Nhung (2012), Research on extracting and refining Conessin, Kaempferol, Nuciferin from medicinal herbs as reference standards, Doctoral thesis in pharmacology, Hanoi University of Pharmacy.
- Lu Thi Kim Chi, Nguyen Ngoc Vinh (2012), Isolation and establishment of standard substances phyllanthin from bitter melon (Phyllanthus amarus Schum et Thonn), Journal of Pharmacology, 52 (6).
- Thai Nguyen Hung Thu, Nguyen Thai An, Hoang Lan Nhung, Hoang Thi Tuyet Nhung (2010), Research on refined extract of Kaempferol from red leaf monocotyledon as a reference in testing, Journal of Pharmacology, 408
- Do Thi Thanh Thuy (2008), Research on establishing standard emodin from Rhubarb for drug quality control, Master's thesis in pharmacology, Hanoi University of Pharmacy.
The Saigon Center for Pharmaceutical Science and Technology has registered with the Ho Chi Minh City Department of Science and Technology to implement the project: "Preparation of reference standards for quality testing of herbal and traditional medicines". As a result, 10 standard substances were extracted, isolated and prepared from medicinal herbs including oleanolic acid, asiaticosia, berberin chloride, curcumin I, damnacanthal, diosgenin, mhesperidin, ginsenoside-Rb1, ginsenisod-Rg1 and majonoisid-R2. These 10 standards have been validated and evaluated by three independent laboratories, meeting GLP/ISO standards.
