In general, laboratory is a facility, which provides adequate and sufficient services. The services include availability and supply of chemicals, instruments, energy (viz electrical, thermal etc), utilities (viz water, steam, air and other gases etc) as well as different laboratory equipment to keep the laboratory operating either ‘as and when’ required or continuously and efficiently. Like other industries, laboratories in pharmaceutical industries should have adequate space; designated areas for particular operations, proper equipments, adequate quantity and quality chemicals and trained personnel to design an appropriate plan to meet the either in-house needs or needs of customers and perform experiments safely.
Laboratories in pharmaceutical industries require sophisticated equipment, besides sophisticated instruments and pure/ultrapure chemicals. A modern R&D laboratory in pharmaceutical industries employed different technicians and so different types of equipments such as analytical balance, refrigerator (– 4 to – 8°C), spectrophotometer, flow cytometer, microscopes 9 dissecting as well as inverted), cell counters, incubators, microscope etc., are made available. New laboratories may not have an established range of workload due to regional and market variations and thus should always keep in mind plans for future expansion.
There are two types of laboratory equipment, manual and automation equipment. The latter category is of two types’ viz automatic devices and automated devices. Automatic devices perform specific operations at a given point in an analysis, frequently the measurement step while automated devices can control and regulate a process without human intervention, an attribute that causes them to be used in process control systems.
The selection of a laboratory equipment depends on the purposes for which it is desired. Equipment performs one special duty and is operating based on certain principles. Some of the commonly used laboratory equipment in pharmaceutical industries are discussed below.
The laboratory shall be furnished with all items of sampling, measurement, and test equipment required for the correct performance of the tests and/or calibrations (including sampling, preparation of test and or calibration items, processing and analysis of test, and/or calibration data). Equipment and its software used for testing, calibration, and sampling shall be capable of achieving the accuracy required and shall comply with specifications relevant to the tests and=or calibrations concerned. Calibration programs shall be established for key quantities or values of the instruments where these properties have a significant effect on the results.
Commonly used laboratory equipment
Measuring and test equipment (M & TE): These include calibration instruments, dimensional measurement, electrical and electronic test equipment, electronic meters and testers, environmental test equipment,equipment that evaluate mechanical, thermal or other material properties etc and all of the measuring instruments, measurement standards, auxiliary apparatus and instructions that are necessary to perform a measurement. This term includes measuring equipment used in the course of testing and inspection, as well as that used in calibration. It may be noted that, the term measuring and test equipment is taken to encompass measuring instruments and measurement standards.
Filtration equipment: Filtration is a mechanical method used to separate solids from liquids or gases by passing the feed stream through a porous cloth, sheet or membrane, which retains the solids and allows the liquid to pass through. It is very common equipment in chemical, metallurgical and pharmaceutical laboratories. Filter papers and cloths in different materials viz cotton, polypropylene etc. are used in filtration equipment, Buchner funnel or in simple laboratory funnel. Filter papers come in a broad range of glass fibre, qualitative and quantitative types for all needs.
Crystallizer: Crystallization is the formation of solid particles within a homogeneous phase. It may occur as the formation of solid particles in a vapor, as in snow; as solidification from a liquid melt, as in the manufacture of large single crystals; or as crystallization from liquid solution. Crystallization is also a novel purification process and crystallizers are often used in laboratory. Crystallization for purification process in laboratory operates at lower pressure and temperature and energy consumption is low. In analytical and synthetic chemistry work, impure reagents of doubtful purity are recrystallized after dissolving in a very pure solvent, and then crystallized to get pure reagent.
Centrifuge: Centrifugation is a process in which light particles are revolved over high speed with the help of electric motor so that the fine particles which do not settle at bottom would settle down. Centrifuge machines are commonly used in pharmaceutical laboratory.
Mechanical centrifuges, high-speed machines, are used for separating liquid-liquid dispersions, for example, in the separation of caustic solutions and oils. By enhancing the settling rate (without, however, influencing coalescence), they reduce the settling time considerably. For granulation it is commonly used, as relatively dry materials such as centrifuge cakes can sometimes be granulated to give a suitably porous bed on the conveying screen.
Mixing equipment: Mixing equipment are very common in a laboratory. There are different types of mixing equipment used in pharmaceutical laboratories based on the flow patterns during mixing. There are three types of mixing flow patterns that are markedly different. The so-called axial-flow turbines actually give a flow coming off the impeller of approximately 45°, and therefore have a recirculation pattern coming back into the impeller at the hub region of the blades. This flow pattern exists to an approximate Reynolds number of 200 to 600 and then becomes radial as the Reynolds number decreases. Radial-flow impellers include the flat-blade disc turbine. This generates a radial flow pattern at all Reynolds numbers.
Evaporators: Evaporation is used to remove volatile liquids from non-volatile solutes which cannot be done through filtration due to the small size of the substances. The most important consideration in controlling the quality of concentrate from an evaporator is forcing the vapor rate to match the flow of excess solvent entering in the feed. Most evaporators are heated by steam condensing on metal tubes. Nearly always the material to be evaporated flows inside the tubes. Usually the steam is at a low pressure, below 3 atm. abs; often the boiling liquid is under moderate vacuum, at pressures down to about 0.05 atm. (abs). Reducing the boiling temperature of the liquid increases the temperature difference between the steam and the boiling liquid and thus increases the heat-transfer rate in the evaporator.
Solvent extractors: In this process, a mixture of two components is treated by a solvent that preferentially dissolves one or more of the components in the mixture. The mixture so treated is called the raffinate and the solvent-rich phase is called the extract. The component transferred from raffinate to extract is the solute, and the component left behind in the raffinate is the diluent. The solvent in the extract leaving the extractor is usually recovered and reused. In extraction of solids, or leaching, soluble material is dissolved from its mixture with an inert solid by means of a liquid solvent. The dissolved material, or solute, can then be recovered by crystallization or evaporation.
Adsorption: This technique is used to remove impurities from chemicals by trapping it on the surface of solid adsorbents such as activated carbon which forms strong physical bonds with the impurity. It is not easy to remove very minute particles by filtration because such particles tend to clog the mesh. In such cases use of a filter aid that can selectively adsorb minute impurities is recommended. Any filter aid will do if it is porous, hydrophilic or solvophilic and has a rigid lattice. Celite, diatom earth and activated clay are frequently used. Activated charcoal has a wide surface area and can adsorb many organic compounds and is frequently used to remove smelly substances (in most cases organic compounds) from the air or water. Silica gel can adsorb water and is widely used as a desiccant.
Chromatography: Chromatography is a separation process where a portion of a solute mixture (feed) is introduced at the inlet of a column containing a selective adsorbent (stationary phase) and separated over the length of the column by the action of a carrier fluid (mobile phase) that is continually supplied to the column following introduction of the feed. The mobile phase is generally free of the feed components, but may contain various other species introduced to modulate the chromatographic separation. The separation occurs as a result of the different partitioning of the feed solutes between the stationary phases; the separated solutes are recovered at different times in the effluent from the column. Chromatography is used both in analysis of mixtures and in preparative and process-scale applications. It can be used for both trace-level and for bulk separations both in the gas and the liquid phase. Packed bed column is used for chromatography.
Distillation: Distillation is commonly used in laboratory to separate two miscible liquids based on the difference in the boiling point. Different types of equipment are used to carry out distillation operation. Packed beds with different types of internal packing are commonly used to perform distillation along with re-boiler and condenser.
Based on application,different types of equipment are used in pharmaceutical laboratory, which are either developed indigenously by a company and modified conventional laboratory equipment as per specific requirement. Some of these equipment are costly, e.g for the synthesis of drugs, such as fentanyl and lysergic acid diethylamide, requires much higher levels of expertise and sophisticated equipment.
(The author is a practicing chemical engineer based in Mumbai)