Introduction
The aim of aseptic technique during pharmaceutical formulation is to achieve asepsis to prevent the access of microorganisms into the formulation during the preparation and testing of the product.
Sources of Contamination of pharmaceutical Formulations
The following are the common sources of microbial contamination:
1. Atmosphere
The atmosphere has no microbial flora of its own because it cannot support the growth of microorganisms. However, as the appearance of a ray of light in a darkened room reveals, it is found to be heavily contaminated with varied particles of solid materials mostly associated with microorganisms. The contaminating microorganisms come from the following sources.
- a. Dust: the microorganisms come from the soil. The organism may be staph aureus, Bacillus spp, Clostridium welchi, Clostidium tetani and even Mycobacterium tuberculosis.
- b. Droplets: From the respiratory tract by coughing and sneezing e.g Staph.aureus, -Haemolytic streptococci spps; common cold influenza, virus infections such as corona virus can be spread easily from sneezing droplets. As the droplets evaporate, the left over contain dried saliva or mucus with the residue consisting of tiny protein flakes carrying many different microorganisms.
- c. Free Microorganisms: Pathogenic bacteria and viruses obtained from dust droplets or nuclei are not common. Naked yeasts and mould spores are often abundant.
2. The breath
Staph aureus, streptococci spps, micrococci etc can be spread from the respiratory tract through unprotected coughing, sneezing, spitting etc.
3. The Hands:
Major means of transmitting bacteria infections. Washing of hands with soap must be frequently done before handling the pharmaceutical ingredients.
4. Hair:
Hair in the head is always exposed to atmospheric dust encountered during walking, motion and the shaking of the head. Female workers should be very mindful of this.
5. Clothing:
Particulate matter of clothes can be grossly contaminated.
6. Working surfaces:
A potential source of contamination because microorganisms will and can easily drop on them.
7. Equipment:
A protential source of contamination of fluids etc. The equipment used must be disinfected and properly cleaned before every experimental procedure
8. Containers, glasswares, spoons etc used:
These materials must be thoroughly washed with soap or any degreasing agent and dried in any oven before use.
Factory and Hospital Hygiene and Good Manufacturing Practice (GMP)
The quality of a pharmaceutical product whether manufactured in an industry, factory or in a hospital cannot be ensured solely by examining in detail a small number of samples taken from a completed batch.
For instance, a low level of microbial contamination or uneven distribution of microbial contamination may not be detected by conventional methods of sampling and sterility testing. Instead a product must be manufactured in a suitable environment by a procedure which minimizes the possibility of contamination occurring, and at the end of it tests can be performed as confirmation of contamination prevention or as an additional safe guard against gross contamination.
Therefore measures essential for the control, during manufacture ensuring good quality product and preventing microbial contamination are considered.
Unique Definitions
Manufacture:
This s defined as a complete cycle of production of a medical product. This cycle include the acquisition of all raw materials, then processing with final product and its subsequent packaging and distribution.
Quality assurance:
This is the sum total of the arrangements made to ensure that the final product is of the quality control for its intended purpose. It c b onsists of good manufacturing practice plus factors such as original product design and development.
Good Manufacturing Practice (GMP).
GMP comprises that part of quality assurance of a production process which is aimed at ensuring that a product is consistently manufactured to a defined quality requirement appropriate to its intended use.
Good Manufacturing Practice Requires
- The manufacturing process is fully defined before it is commenced.
- Provision of the necessary facilities in adequate quantify.
- Conducive environment of manufacture or production.
These include that there will be adequate trained personnel to carry out the manufacturing processes, suitable premises, suitable equipment, correct materials used, approved methodological procedures of manufacturing adopted, suitable storage and available transport facilities. Lastly, appropriate and adequate recording of all transactions (financial and non-financial) must be available.
Quality Control
Quality control in GMP ensures:
- That at each stage of manufacture, the necessary tests are carried out.
- The product is not released until it has passed all the necessary quality control tests.
In process control
This comprises any test on a product, and consideration for the provision of adequate environment or the equipment for the manufacturing process.
Control of Microbial contamination during manufacture:
General Aspects:
- a. Environmental cleanliness and hygiene:
- b. Quality of starting material
process design - c. Quality control and documentation
packaging, storage and transport.
Manufacturing of sterile products
Clean and aseptic areas general consideration:
Aseptic Areas:
During the manufacturing process of a pharmaceutical product, the product can be contaminated by various means at various stages of production.
There are several ways of minimizing these risks during industrial and hospital production processes.
The Following Ways of Contamination Control as Considered.
(a) Environmental cleanliness and hygiene:
From the environment, these are the following sources:
- working surface
- Fixtures and equipment
- poled stagement water in the area of production.
Therefore, all premises, including processing area, stores and laboratories must be maintained in a clean, airy, dry and tidy conditions. The walls and ceiling must be properly cleaned and made impervious, and of washable surfaces with high grade tiles. The floor should be of high grade tiles made of imperious material free from cracks and open joints so that microorganisms cannot be harboured. Sterilized air with filters and control of dust in the laboratory should be upheld. Stagnant water could be a potential source of contamination when it is inhabited by microorganisms. This pooled surface water should be dried up and prevented from harbouring contaminants. Microorganism can thrive in certain liquid preparations, creams and ointments. The manufacture of these products should be in a clean environment and in a closed system. This could serve a dual purpose whereby the products do not get in touch with air-borne microbial organisms, but also against evaporation loss. Personal hygiene must be maintained in the environment where sterile products are prepared. The personnel must be free from communicable diseases and not have any open lesion on the exposed body surfaces. Adequate hand washing facilities and protective garments including head gear and nose masks much be provided and worn by the working staff. There should be no direct contact between the material and the uncovered operative hands of the personnel. Where necessary glove must be worn, Staff must be trained in the principle of GMP and personnel employed in the manufacture of sterile product should receive basic training of safe procedure of routine microbiological processes.
(b). Quality of starting materials
Raw materials are potential sources of contamination. Raw materials include all basic necessities needed as ingredient for the formulation of the product including water supply. Materials of natural origin are usually associated with an extensive microbial flora and require careful storage to prevent grow of the organisms and spoilage of the material. If the raw material can be stable, suitable sterilization may be necessary for them before use. Staff handling raw materials need to receive adequate training to prevent the transfer of contaminants from one raw material to another or to the final product (cross-contamination).
Animal raw material sources
- Gelatin
- Desiccated thyroid
- Pancrease
- Corchineal
All of these listed above may be contaminated with animal-borne pathogens.
For this reason, BP(1980) required they be free from E.coli and Salm. spp before they can be used for the preparation of pharmaceutical product.
Microflora of material from plant origin such as gum, accacia, tragacanth, agar, powdered rhubarbs, starches may arise from the indigenous plants eg Erwinia Spp, Pseudomonas spps, Lactobacilus spp, Bacillus spp and Streptococci spp, moulds such as Cladosporium spp, Fusarium spp etc.
Water:
- Portable water mains or portable mains water
- water purified by ion exchange
- reverse osmosis
- Distillation
- Water suitable for injection only (water for injection BP).
All the above when required for the manufacture of parenteral products must be pyrogen-free (apyrogenic).
Pyrogens are not volatile, they may not +be removed by ordinary distillation process. Since some may be carried over mechanically into the distillate with the entrainment spray. Therefore a spray trap consisting of baffles is fitted to the distilling flask to prevent spray and pyrogens from entering the condenser tubes. Water prepared in this manner can be used immediately for the preparation of injection provided they are sterlised within 4hrs of water collection. Alternatively the water can be kept for longer period at a temperature of above 65oC (usually 80oC) to prevent bacterial growth with subsequent pyrogen production. UV light may be useful in reducing the bacterial content at 254nm, but not to be regarded as being a sterlising agent.
(c) Process Design:
This relates to a situation where the manufacturing process must be well defined to yield a product that is microbiologically acceptable and conforms to defined specification. Therefore the process must be such that it can be suitable for routine production process.
d. Quality control and documentation
- Starting materials must have low microbial content to control the contamination level in the final product and environment.
- Acceptable microbiological standards for all the raw material must be defined.
- Microbiological quality controls to monitor microbial load of the environment by microbial counts and validation of cleaning and disinfection procedures.
- Sterile product manufacture will be followed by tests to ensure the operator’s technique, monitoring of air filters and sterliser efficiency. This must be followed finally with sterility testing of the finished products.
Finally, proper documentation must be practiced. This entails documentation of each batch of products, details of starting materials, packaging materials intermediate bulk and finished products.
The information obtained is of importance to determine the resolution of problems that may arise should a defective batch needs to be recalled.
Packaging, storage and transport:
Even often following the proceeding steps and stringently control contamination, contamination could still arise during storage and transport. Therefore, it is mandatory to ensure that the packaging used for the final product, storage conditions and transportation conditions and process must minimize or preferably prevent deterioration or contamination.