Automation in Pharmaceutical Manufacturing

Slide 1:

Introduction- Automation mean self dicated .it is the use of control system such as computer to control industrial machinery and processes reducing the for human intervention .automation greatly reduces the need for human sensor and mental requirements as well as processes and system can also be automated. E.g. Telephone operators have been replaced largely by automated telephone switchboard and answering machine. Advantages- Advantages of automatic control, over manual control, are as follow – • Processes are controlled more precisely resulting in more uniform and high quality product. • Processes are to fast to be controlled by manual operators can be easily controlled by automatic system. • Automatic control is beneficial in certain remote, hazardous or routine operations. • No batch to batch variation, lead to greater demand for product and higher profits. • Increase production capacity and flexibility. • Decreased product throughput time. • Decrease labour cost. • Increases processes reliability.

Slide 2:

GENERAL AUTOMATIC CONTROL SYSTEM- In heat exchange process- In this process, the in flowing liquid is to be heated to the required temperature steam flowing through heating coils. The temperature of exit flow is affected by the processes variable such as-temperature and flow rate of the flowing liquid, temperature and flow rate of the steam, heat capacity of the fluids, and heat loss from the vessel and mixer speed. Type of system in heat exchange process- a) open loop system b) closed loop control system-1) Feed back control system 2) Feed forward control system Open loop system-Are those in which information about the controlled variable (like temperature ) is not used to adjust any of the system inputs to compensate for variation in the processes variables. Closed loop control system- Is one where control variable is measure and the result of this measurement is used to manipulate one of the processes variables, such as steam flow

Slide 3:

Closed loop feed back system – In this system, information about the controlled variables is feed back as the basis for control of a process variable by a human operator (manual control) or by use of instruments (automatic control). In manual control system, an operator periodically measures the temperature of liquid. If for example, the temperature is below the desired value, he increases the steam flow by opening the valve slightly. For automatically controlled system , a temperature sensesitive device is used to produce a signal proportional to the measured temperature .this signal is feed to controller which compare it with a preset desired valve (set point ). If differences exist, the controller changes the opening of the steam control valve to correct the temperature Closed loop feed forward control – In this process disturbances are measured and compensated without waiting for a change in the controlled variable to indicate that a disturbance has occurred. This type of control is useful when the final controlled variable can not be used.

Slide 4:

AUTOMATIC CONTROLLER – Industrial automatic process controller varies from simple on off device to special purpose computing instruments. Three general type of controller- 1) self operated controller- a)on off controllers b) Proportional controller 2) electronic controller 3) pneumatic controller 4) Miscellaneous controller – hydraulic, fluidic and special response controller. 1) self operated controllers- Some control systems obtain the power require to operate the error detector and final control element from the controller medium of the process by way of the sensing element .such controller are self operated controller , used for temperature , liquid and pressure controller . There are two type of self operated controller – a) On off controller – in this controller, the amount of control action applied at the process input is either zero or the maximum available. b) Proportional controllers- The action of a proportional controller is smooth and continuous over the operating range. For example in a steam-heated process vessel, if the temperature to be controlled increase above the set point, the controller output well increase a proportional amount. This output may reduce the amount of heat being added

Slide 5:

2) Electronic controllers- Are extensively used for process control .the reason for their increase usage are- *solid state circuit * Easier servicing * Smaller particle size * can easily be linked with process control computer * cost completive compare to pneumatic controller * may be more accurately tuned. 3) Pneumatic controller- Its basic purpose is to supply compressed air to a pneumatic valve actuator in response to an error signal, based on the deviation of measured variable from the set point. Computer process control – in the hierarchy of computer control of a process. Five levels can be identified- 1) unit operation control 2) unit process control 3) plant control 4) Departmental and corporate control level of a company. Without computer control at the plant or unit process level, the study state plant operating period tend to become, several days.

Slide 6:

Process control computer- 1. Analog computer 2. Digital computer Analog computer- represents the numbers being manipulated by the magnitude of a physical quantity, such as volts or pressure. Mathematically operations are carried out in a continuous manner. Digital computers- are counting device that operates directly on numbers to perform the four fundamental mathematical operation addition, subtraction, multiplication, and division.

Slide 7:

PROCESS MEASUREMENT Instrument for Measuring Vacuum 1- Compression gauge- e.g. McLeod Instruments – In this instrument a pool of mercury is arranged so that by raising a reservoir or by turning the instrument, it seals off a pocket of vacuum space & then compress it into a known compression ratio .it can read down to 10-4 to 10-6 torr. 2- Simple manometer. 3- Thermal (Pirani type) gauge. 4- Diaphragm gauges. 5- Radiometer gauges, Knudsen type. – If two parallel plates are suspended in rarified gas and one of them is heated, then a disbalance of molecular bombardment results which tend to force the plates apart. This is significant only when the mean free path of molecules is large relative to the size &spacing of plates. Gas molecules which have made contact with the hotter plate have a higher average velocity than other in the system, including those from the cold plate & these differences can be calculated from kinetic theory.

Slide 8:

TEMPERATURE MEASUREMENT-; 1- THERMOCOUPLES- Principle – An electric current flows in a continuous circuit of two different metallic wires, if the two junctions are at different temperature. A& B are the two metals &T1&T2 are the temperature of the junction. If t1is the colder junction & thermoelectric current I flows in the direction indicated, metal A is referred to as thermoelectrically positive to metal B. The thermal emf is a measure of the differences in temperature between T2&T1 2- Resistance thermometer 3- Filled in thermometer 4- Bimetal thermometer 5- Liquid in glass thermometers. 6- Pyrometers. PRESSURE MEASUREMENT DEVICES-: 3 types 1- Based on measurement of height of liquid column. 2- Based on measurement of the distortion of an elastic pressure chamber. 3- Electrical sensing devices.

Slide 9:

1-Liquid column pressure measuring device. Manometer- in this the pressure being measured is balanced against the pressure exerted by a column of liquid. If the density of liquid is known the height of the liquid columns is a measure of the pressure. These types of device are commonly called manometer. 2- Elastic element pressure measuring devices- are those in which the measured pressure deforms some elastic material (usually elastic) within its elastic limit, the magnitude of the deformation being approximately proportional to the applied pressure.

Slide 10:

These devices may be broadly classified into 3 types. a. Bourdon type e.g. C- spring bourdon b. Bellows type c. Diaphragm type. 3- Electric sensing devices-: • e.g.- Strain gauge -: when a wire or other electrical conductor is stretched elastically , its length is increased & its diameter is decreased Both these dimensional changes result in an increases in electrical resistance of the conductor. LEVEL MEASUREMENT – This may be defined as the determination of the location of the interface between two fluids separated by gravity, with respect to a fixed datum plate .the most common level measurement is that of the interface between a liquid & a gas. Types of devices 1-Visual types 2- Float actuated types 3- Displacer type. 4- Head devices. 5- miscellaneous. 1-Visual type -: these device include • Dip stick. • Tape & plumb bob. • Open manometer. • Gauge glass.

Slide 11:

2. Float actuated devices -: these contain a buoyant member which floats at the interface between two fluids. These devices are usually limited to liquid - gas interfaces. Types -: 1- Chain or tape float gauge. 2- Lever & shaft mechanism. 3- Magnetically coupled devices. 3- Displacer devices -: displacer actuated level measuring devices use the buoyant force on a partially submerged displacer as a measure of location of the interface along the axis of displacer. Physical property measurement-: these include measurement of 1. Density & specific gravity. 2. Viscosity & consistency. 3. Refractive index. 4. Thermal conductivity. 5. Boiling point. 6. Flash point. Process chemical - composition analyzers. 1. Chromatographic analyzers. 2. Infrared analyzers. 3. U.V. & visible radiation analyzers. 4. Turbid metric analyzer. 5. Paramagnetic & nephelometric analyzer .

Slide 12:

Electro analytical instruments. 1. Conductometric analysis. 2. Oscillometric analysis. 3. Potentiometric analysis. 4. Measurement of pH. 5. Polar graphic analysis

Slide 13:

AUTOMATION IN TABLET MANUFACTURING Benefits of automation in tablet production. 1. Improve material handling. 2. Improve specific unit operation. Unit operations in tablet manufacturing. 1. Particle size reduction 2. Sieving 3. Mixing. 4. Particle size enlargement. 5. Drying. 6. Compression. 7. Sorting. 8. Coating. 9. Packaging. 3. Eliminate or combine processing steps 4. Incorporate automated process control of unit operation and processes.

Slide 14:

MATERIAL HANDLING RISKS-: 1.Customer dissatisfaction. 2. Increased product cost. 3. Employee safety liabilities. Basic principles of material handling 1. Short distances. 2. Short terminal times. 3. Two way pay load. 4. Avoid partial loads. 5. Avoid manual handling. 6. Move scrap cheaply. 7. Gravity is cheapest power. 8. Move in straight lines 9. Unit loads 10. Label thoroughly.

Slide 15:

Examples of material handling improvement • Granulation and tableting sections of the computer controlled tablet manufacturing process by Merck Sharp & Dohme (MSD) and Eli lily and company. Advantages 1. No human handling of material 2. The system is built in 3 story building which incorporate vertical drops to utilize gravity whenever possible and uses pumps, vacuum, bucket conveyors to move material upward whenever necessary. Processing step combination or elimination Direct compression (new process) 1. Raw materials. 2. Weighing and measuring (automatic weigher and recording system.) 3. Gravity feeding 4. Compression (high speed rotary press) 5. Aqueous coating (Hi coater).

Slide 16:

Wet granulation -: standard processing steps Load processer Weigh ingredients Mix, mass, agglomerate, dry lubricate Transfer (store) Compress Continuous batch powder mixing and massing equipment E.g. Dionsa mixer & granulator is a high – shear powder mixer and processor

Slide 17:

Coating process improvement-: coating of tablets and pills using coating pan is entirely operator dependent. Typical Accela cota- : for aqueous or solvent film coating. This is a side vented or perforated coating pan. Advantages 1. One way flow of air through the tablet bed and out the perforation of the pans. These greatly reduces or eliminate the bounce back of atomized spray and particle spray drying of the spray droplets that occurs especially with solvent based coating with conventional pans. 2. It benefits coating because the greater air flow through the bed facilitates drying. 3. Used for continuous coating of film and sugar systems. Basic process control devices • Sensors -: it is a device to measure the variable of the process which must be considered in making control decisions. • I-O devices-: transforms the signals from the sensors into signal that are usable by the computer. • Computer-:programmable controller • Microcomputer-: • Minicomputer • Activators -: take the command from the computer via the I-O devices and turn them into action in the process.

Slide 18:

REFERENCES -: 1- Lachman Leon and Schwartz .B. Joseph Pharmaceutical dosage forms: Tablets. Vol 3, edition 2. P.P 1-74. 2- Sambhamurti B.S., pharmaceutical engineering.

Slide 19:

THANK YOU