Heavy Metals and Microbial Contamination in Medicines

1. Heavy Metals and Microbial Contamination in Medicines With the rapid population ageing of the world, the medicine and health problems of urban elder in many countries such as Japan and China are standing out. For the human society, drug is a special commodity, which is characterized by complexity of types, medical specificity, and strict quality standards. It is not like other goods with quality grade to divide such as excellent, first class or second class. There is the only difference between compliance and non-compliance in medicines. Generally, all medicines, whether they are synthetic or of plant origin, should meet the basic requirements of safety and effectiveness. However, the most serious drug pollution is heavy metal or microbial pollution in the production and storage of medicines. Therefore, heavy metals and microbial contamination become the key factors for their quality assessment and quality control to ensure the drug safety, purity, potency and efficacy. Heavy Metals Analysis Usually heavy metals refer to a general term of all metals that can be reacted with thioacetamide, hydrogen sulfide or sodium sulfide to produce a color change in the pH 3.5 of acetate buffer solution, These metals include silver, lead, mercury, copper, cadmium, bismuth, antimony, tin, arsenic, nickel, cobalt, zinc, and so on. The contamination of these heavy metals to the drugs exists in raw materials, excipients and preparations and so on. For example, some mineral drugs themselves contain heavy metals, such as cinnabar and realgar, and some other herbal medicines are accumulated heavy metals during planting due to the pollution from the water or soil, while sometimes we need to use some heavy metals to act as carrier or catalyst in the production of excipients and preparations, which may directly lead to high levels of heavy metals in the drugs. No matter how the contamination by toxic metals either be accidental or intentional, these toxic metals can pose clinically relevant dangers for the health of the user and should therefore be limited. For example, when the mercury content is up to 200 ug/L in the blood, it can lead to the renal dysfunction, tremor and even paralysis; Tin

2. and its organic compounds are deadly poisonous, of which more than 250 mg / kg content can lead to severe brain edema; Cadmium is a commonly known poison substance that can accumulate in the body for a long time, which has been identified as IA carcinogen by International agency for research on cancer (IARC). All in all, the contamination of drugs by toxic metals is a threat to human body and it is necessary to be qualitative and quantitative analysis for our health life. Generally, the main methods commonly used for detection heavy metals are atomic absorption spectrophotometry (AAS), inductively coupled plasma (ICP) and neutron activation analysis (NAA). Atomic Absorption Spectrometry (AAS): Atomic Absorption Spectrometry (AAS) Atomic absorption spectroscopy (AAS) is a spectroanalytical procedure for the quantitative determination of chemical elements using the absorption of optical radiation (light) by free atoms in the gaseous state. There are four kinds of atomizer: flame atomizer, graphite furnace atomizer, hydride generation atomizer and cold vapor atomizer. Flame atomic absorption spectrometry (FAAS) have many merits, such as low cost, easy operation, fast analysis speed, good selectivity, and the signal is stable in the measurement of high concentration heavy metal elements. It is the most widely adopted method to detect the heavy metal in recent years. Graphite furnace atomic absorption spectrometry (GFAAS) has the advantages of high sensitivity and low detection limit. The relative standard deviation (RSD) of the measured values can usually be controlled within 5%. At present, it is one of the most important

3. methods for the determination of trace heavy metal elements. When GFAAS is used for the determination of trace heavy metal elements, it often needs to add appropriate matrix modifier to eliminate the interference of the matrix, and make the analyte to be fully released to reduce the ash loss. Hydride generation-atomic absorption spectrometry (HG-AAS) is an efficient separation, enrichment and sampling technique, which measures elements by reacting with reducing agents in an acidic environment at room temperature to form gaseous hydride or atomic vapor, and then separate from the substrate. This method can greatly improve the sensitivity and injection efficiency, and significantly reduce the matrix interference, which can determine the elements such as arsenic, germanium, tin, selenium, bismuth, antimony, mercury, lead and tellurium. Cold vapor-atomic absorption spectrometry (CV-AAS) is a specific method to determine the micro-content element of mercury. This method for measuring and tracing mercury has high sensitivity and accuracy features. Dai yihua used CV-AAS for detecting mercury in medicinal materials, of which the detection limit is 0.334 ug/g, the RSD is less than 5%, and the recovery is between 98% and 104%. Inductively Coupled Plasma Methods (ICP-AES, ICP-MS): Inductively coupled plasma methods include inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Inductively coupled plasma (ICP) as a kind of the atom spectrum analysis technique began in the 1960s, and by the 1980s, theory and application entered its mature stage. It is an analytical technique mainly used for the detection of trace metals. ICP-AES ICP-MS

4. ICP-AES also referred to as inductively coupled plasma optical emission spectrometry (ICP-OES). It is a type of emission spectroscopy that uses the inductively coupled plasma to produce excited atoms and ions that emit electromagnetic radiation at wavelengths characteristic of a particular element. ICP-AES shortens the analysis time and improves the analysis efficiency, and can simultaneously determine various metallic elements, which make up the defect of atomic absorption spectrometry. Therefore, it has some advantages in the analysis of trace elements due to its high sensitivity, low detection limit, high precision, wide linear range, multi-element simultaneous analysis and small matrix effect. It has become one of the most effective methods for the detection of metallic elements, and is widely used in the detection of heavy metal content in various medicinal materials. ICP-MS is also an elemental analysis method that uses the plasma as ion source, and can simultaneously determine multiple elements, which has high sensitivity and can be combined with other chromatography to analyze element valence state. Atomic Fluorescence Spectrometry (AFS): The principle of AFS is that when the sample is excited by radiation energy, the atomic vapor of the metal will produce fluorescence effect and can be measured through the strength of fluorescence. Atomic fluorescence spectrometry has high accuracy without requiring separation, enrichment and other steps, but only have fluorescence effect on special metal ions. Therefore it cannot detect all metal ions, which limits the application of this detection technology. Microbial Contaminantion Analysis Medicines may be associated with a broad variety of microbial contaminants, represented by bacteria, fungi, and viruses. Inevitably, this microbiological exerts an important impact on the overall quality of medicines. The survival of any microorganisms in the sterile preparation may contribute to serious or fatal injuries for the drug user, and the aseptic testing of drug is the highest requirement for the microbiological limit testing in drug quality management. The pharmacopoeia of many countries has described in

5. detail about the microbiological detection of drugs, and formed consistent detection standards and operating procedures, which judge the product sterility by visual inspection the turbidity of culture medium. With the progress of science and technology, many kinds of new and high techniques have been widely recognized and applied in the field of microbial identification and classification, such as bioluminescence detection, laser scattering detection, mass spectrometry, PCR, DNA sequencing, and so on. Adenosine Triphosphate (ATP) Luminescence Detection Adenosine triphosphate measurement based on bioluminescence is a rapid method for detecting contamination in injectable preparations. ATP exists in all organisms, which can react with luciferase and generate the photons. ATP can be quantitatively analyzed by the intensity of photons which are detected by a highly sensitive detector. However, this method still requires a long time for detection, and the reagents are expensive and the instrument needs high requirements for cleanness. Although the experimental results are directly related to the luminous intensity of ATP, different growth environments and states of microorganisms caused the outputs of ATP to be different, which increases the suspiciousness between the experimental results and microbial quantity. PCR/ Gen-probe It mainly includes protein analysis and nucleic acid analysis (plasmid analysis, hybridization, PCR, gene sequence analysis). Microbial protein analysis is mainly based on the characteristic electrophoresis figure which is produced by microbial protein electrophoresis under standard conditions. As the expression of protein is affected by environmental factors, it is necessary to require the standard growth environment for the bacterial strain. Nucleic acid analysis is studied on the basis of DNA. It can quickly determine the classification of a certain microorganism or establish a new classification for special microorganisms that are difficult to culture. Flow Cytometry This detection technology is based on the functional level of single cells or other biological particles to conduct the quantitative analysis and separation tests. It can

6. analyze thousands of cells in a very fast speed, and can simultaneously get multiple parameters from a measured cell. It has advantages of high speed, high precision and good accuracy compared with the traditional spectroscopy and becomes the most advanced quantitative analysis cell technology in the contemporary. References 1. Kunle, Oluyemisi F, Egharevba. (2012) ‘Standardization of herbal medicines - A review’,Int. J. Biodvers. Conserv, 4(3):101-112. 2. A Decool,V Goury, A Tlbl,S Chbaud, F Vmcent, et al. (1991) ‘Detection of bacterial adenosine triphosphate through bioluminescence, applied to a rapid sterility test of injectable preparations’,Analytzca Chlmrca Acta, 255: 423-425. 3. Chollet R, Kukuczka M,Halter N,et al. (2008) ‘Rapid detection and enumeration of contaminants by ATP bioluminescence using the milliflex rapid microbiology detection and enumeration system’,Journal of Rapid Methods & Automation in Microbiology,16(3): 256-272. 4. Kaleta E J,Clark A E,Cherkaoui A,et al. (2011) ‘Comparative analysis of PCR- electrospray ionization/mass spectrometry (MS) and MALDI-TOF/MS for the identification of bacteria and yeast from positive blood culture bottles’,Clinical chemistry, 57(7): 1057- 1067. 5. Gunasekera T S, Attfield P V,Veal D A. (2000) ‘A flow cytometry method for rapid detection and enumeration of total bacteria in milk’,Applied and environmental microbiology, 66(3): 1228-1232. 6. J Wang, JN Li, LY Hong, (2015) ‘Recent advances in inspection of heavy metals present as pollutant in medicines’,PTCA, 51(7): 1043-1047. Alfa Chemistry Testing Lab is the world’s leading third-party testing company, which provides one-stop pharmaceutical analysis testing solutions for manufactures, suppliers, retailers, and consumers.

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