Microbial spoilage - Pharmaceutical microbiology (Second year b.pharm) (3rd semester)

Prof.Mr.Kiran K. Shinde (M.Pharm), Assistant professor (VNIPRC)
Pharmaceutical microbiology (Second year b.pharm) (3rd semester)
Introduction
Types of Spoilage
Factors affecting the Microbial spoilage of pharmaceutical products
Sources and Types of Contamination
Assessment of microbial contamination and spoilage

1. MICROBIAL SPOILAGE INTRODUCTION TYPES OF SPOILAGE FACTORS AFFECTING THE MICROBIAL SPOILAGE OF PHARMACEUTICAL PRODUCTS SOURCES AND TYPES OF MICROBIAL CONTAMINATION ASSESSMENT OF MICROBIAL CONTAMINATION AND SPOILAGE PREPARED BY, PROF. SHINDE KIRAN (M.PHARM) ASSISTANT PROFESSOR (VNIPRC) PHARMACEUTICAL MICROBIOLOGY-I SECOND YEAR B.PHARM IIIRD SEMESTER - UNIT 5 Vidya Niketan Institute Of Pharmacy & Research Centre, Bota

2. INTRODUCTION Micro-organisms form an integral part of environment as they are present in air, water, soil, food, etc. Different types of micro-organisms mainly contaminate the pharmaceutical preparations and spoil it. Such spoilage results in major health problems to the users and manufactures. In injections, eye-drops and certain dressings sterility must be seen otherwise infections cause harmful reactions. Oral and topical preparations may cause infections after microbial contamination. Pharmaceutical products may be considered to be microbiologically spoiled if low levels of pathogenic microbes or toxic microbial metabolites are present and detectable physical or chemical changes have occurred in product. O ral formulation contaminated by micro-organisms mainly cause gastrointestinal disorders e.g. Salmonella typhi External semi-solid preparations applied on skin, provide the opportunity for P seudomonas and Staphylococcus and produce localized infections.

3. TYPES OF SPOILAGE

4. Infection induced by contaminated pharmaceutical products Pharmaceutical products may be contaminated by pathogenic micro-organisms mainly from raw materials or at the time of preparations. They cause serious infections to the patients when they use these drugs. Different dosage forms and contaminated micro-organisms which are responsible for diseases are as follows: Contaminating micro-organisms and their infections 2. Physical and chemical deterioration of products The rate of deterioration of ingredients depend upon its chemical structure, physico-chemical properties of a particular environment. Some naturally occurring ingredients are particularly sensitive to attack. Crude vegetables & animal extract often contain wide assortments.

5. 3. Observable effects of microbial attack on products M icrobial spoilage of different dosage forms may be detected by organoleptic tests. These spoiled products may release very unpleasant smelling and tasting such as sour, fatty acids, earthy, amines, and smells. Formulations become coloured green, pink, browny, black, or yellow. Spoiled creams become gritty or lumpy. Surface activity is reduced. 4. Ingredients susceptible to microbial attack Therapeutic agents: Laboratory experiments have demonstrated that many drugs are capable of gross degradation by a wide variety of micro-organisms. Many microbial transformation are useful for production of potent steroids. Aspirin may be converted to salicylic acid and penicillin to inactive products. Surface active agents: Alkali-metal and amine soaps of fatty acids re generally stable due to the slightly alkaline pH of the formulations, which is easily degraded in sewage. The cationic surfactants used as antiseptics and preservatives in pharmacy are slowly degraded at high dilution in sewage.

6. iii. Polymers and humectants: Thickening and suspending agents used in pharmacy are subjected to microbial depolymerisation by extracellular enzymes yielding nutritive fragments and monomers e.g. starch, pectin, dextran, protein, and carboxymethyl cellulose. iv. Fats and oils: This are attacked extensively when dispersed in aqueous formulations such as oil-in-water emulsions. The microbial metabolism of hydrocarbon oils presents a considerable problem in engineering and fuel technology when water is present as a contaminant. v. Preservatives and disinfectant: M ost organic preservatives and disinfectants are metabolised readily by many bacteria and fungi and may serve as growth substrates at concentrations below their effective ‘use’ levels. Degradation is less commonly reported. Many organisms grow in dilute forms. vi. Sweetening, flavouring and colouring agents: M any sugars and other sweetening agents used in pharmacy are ready substrates for microbial growth. Some are used in very high concentrations to reduce water activity. Aqueous stock solution support growth of micro-organisms e.g. peppermint water and chloroform water and colouring agents such as amaranth or tartrazine readily support growth of bacteria and yeasts.

7. FACTORS AFFECTING THE MICROBIAL SPOILAGE OF PHARMACEUTICAL PRODUCTS The physical and chemical status of a pharmaceutical formulation influences the type and extent of microbial spoilage considerably. A specific combinations of conditions within a product may favour its degradation by a particular group of micro-organisms. Factors affecting the microbial spoilage are as follows

8. Size of inoculum: Ingredients contaminated by a high level of micro-organisms cause appreciable microbial degradation. However, inoculum size alone is not always a reliable indicator of likely spoilage potential. Nutritional factors: Gross microbial spoilage of a pharmaceutical product generally requires appreciable growth in the dosage forms. The use of crude vegetable or animal products in formulations provides an additionally nutritious environment. Moisture content: D issolved components of an aqueous formulation may form a complex with water molecules. The high concentration of the solute in the formulation indicates the water activity(Aw) is low. Condensed moisture films can form on the surface of tablets or bulk oils. Temperature: Spoilage of pharmaceuticals may occur over the range of about 10- 60 C. Storage with specific temperature ranges the spoilage. Water for injections should be at 80C prior sterilization, to prevent pyrogen production pH: Extremes of pH prevent microbial attack, although growth of mould is commonly observed in solutions of dilute hydrochloride acid. Preserved flavoured pharmaceutical products can support growth of microbes.

9. 6. Redox potential: The ability of microbes to grow in environment is influenced by its redox balance. Oxygen removal control spoilage in medicines. Due to high solubility of oxygen emulsions become viscous . 7. Protective components: V arious components of formulations and products may increase the resistance and longevity of contaminant micro-organisms. Some substances such as surfactants, suspending agents and proteins can increase the resistance of micro-organisms to preservatives.

10. SOURCES AND TYPES OF MICROBIAL CONTAMINATION The microbiological contamination of pharmaceutical products is influenced by the environment in which they are manufactured and by the materials used in their formulation.

11. Atmosphere: The number of micro-organisms in the atmosphere depends on the activity in the environment and the amount of dust which is present. Air is not a natural environment for the amount of dust is present. Micro-organisms are carried into the atmosphere suspended on particles of dust, skin, clothing, droplets of moisture, sputum from coughing & sneezing. Micro-organisms commonly from the atmosphere are bacteria and fungi. E.g. Bacillus spp., streptococcus spp., Mucor spp., P enicillium spp. Etc. Water: Water is one of the main constituents of many products and it is used for washing and cooling process. Bacillus and Staphylococcus spp. m ay contaminate softened water at the time of its preparation by base exchange method. Different types of micro-organisms are present in fresh water and some microbes may contaminate the water for sewage. E.g. E.coli, clostridium spp. Raw materials: This are potentially rich source of micro-organisms. Synthetic raw materials are usually free from microbes but contamination may occur. R aw materials mainly contain bacteria and fungi e.g. Bacillus spp., salmonella spp., etc. products from animal sources such as gelatine, desiccated thyroid, pancreas, etc. may be contaminated with different pathogens. Process operators: Micro-organisms may be transferred to pharmaceutical formulations from process operators. Natural skin flora micro-organisms are the main source of contamination. E.g. S arcinna spp ., Staphylococcus aureus , etc. other than this they may be transferred from operators as a result of poor personal hygiene

12. 5. Equipment's: It should be simple as possible for the purposes required with minimum of junctions, valves and pumps to allow cleaning in place by circulation of detergents or other chemical antimicrobial agents. The type and growth depend on source of the contamination, environmental conditions and nutrients. 6. Packaging: The microbial flora of packaging materials is dependent upon its composition and storage conditions. Packaging material have a dual role and act both to contain the product and to prevent the entry of micro-organisms or moisture. Containers caps and closures may also be sterilized by moist heat, chemicals, gaseous agents or radiation techniques 7. B uildings : Different molds and a few bacterial species are the most common flora of ceilings and wall. To reduce microbial growth, all walls, floors and ceilings should be smooth and washable. The risk of contamination and spoilage of a pharmaceutical product during formulation, storage and administration to the patient is generally significant and appreciation of this should be reflected in the formulation and design of the product.

13. ASSESSMENT OF MICROBIAL CONTAMINATION AND SPOILAGE 1. 2. 3. 4.

14. Physical and chemical changes: Physical and chemical changes of different pharmaceutical formulations indicate microbial contamination and spoilage. Change in viscosity, pH, emulsion stability and loss of surface activity of formulations indicate microbial spoilage. Measurement of oxygen consumption of the product can indicate the degree of oxidative attack and microbial growth. Sterility test: it is important that materials which are to be tested for sterility are not subject to contamination from the operator during the course of test for this it should be conducted by experienced personnel in an adequately clean room with laminar flow cabinet facilities Assessment of viable micro-organisms in non-sterile products: Non-sterile products are tested for viable micro-organisms for detection of pathogens and total viable counts. Estimation of pyrogen: A pyrogen is a material which causes rise in body temperature when injected into a patient. The lipopolysaccharides and lipoproteins which comprise a major part of cell wall of gram-negative bacteria. Two main procedures are used for the detection of pyrogens.

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