Bar code technology has gained a lot of importance in the field of pharmaceutical sector. Manufacturing, packaging, distribution and hospital pharmacy are some of the areas where bar code has got potential applications.
A barcode is a self contained encrypted message with information encoded within the bars and spaces of specific pattern. The elements of bar code are content, which determines the meaning; data format, which refers to the embedded data and symbology, which describes the "font" in which the machine-readable code is written. Bar codes are read by scanning device that is programmed to analyze the structure of the bars and spaces and transit the encoded data in electronic format. These data can then be stored on a file or transmitted to a computer for processing.
Since the invention of the bar code concept in the United States in the late 1940s, hundreds of bar code symbologies have been developed, but only few of them are actually being used on a large scale. A bar code symbology is a set of rules describing the way bars and spaces have to be organized to encode data characters. A symbology is qualified as being discrete or continuous. In a discrete symbology, the spaces between symbol characters don't contain information as each character begins and ends with a bar. In a continuous symbology, there is no intercharacter gap. i.e., the final element of one symbol character abuts the first element of the next symbol character, and all the elements carry data contiguously. The most popular bar code symbologies are given in table.
Commonly used bar code symbologies
DISCRETE BAR CODES
Code 39
Codabar
Code 2 of 5
CONTINOUS BAR CODES
Interleaved 2 of 5(ITF)
Universal Product code (UPC)
Code 128
Code 93
PDF 417
EAN.UCC system
The purpose of bar code applications is to capture data automatically and to process these data in computer applications. Rules are therefore required to specify the way data should be encoded in a symbol. Similarly, when reading a bar code, there must be a way to know accurately what data has been captured. Three methods exist to specify the rules of encoding and decoding data in bar code symbols:
1. The first method is to establish a one-to-one relationship between the symbology and the data content. In this case, a particular symbology is exclusively reserved to carry certain types of data.
2. The second method is based on conventions defined either by a party for its own applications or established on the basis of mutual agreements between two parties. The conventions describe the symbology to be used and specific rules indicating the way data elements are to be encoded. This method is appropriate only in internal or closed applications, because the rules are relevant only to the parties agreeing to follow the convention.
3. The third method is based on the concept of data identifiers, which are prefixes used to define data fields. Each prefix uniquely identifies the meaning and the format of data field following it. Two sets of identifiers have been standardized and are used in many bar code applications.
Many types of devices are commercially available to read bar codes, which includes a wide range of equipments, such as pen or slot readers, single beam or moving beam scanners, cameras or omni directional scanners. These all illuminate the symbol and analyze the resulting reflectance. Areas of high reflectance are interpreted as spaces, while areas of low reflectance do represent bars. The reflected pattern of bars and spaces is converted to an electrical signal that is then digitized. The decoder assigns a binary value to the signal and forms a complete message. The message is checked by the decoder's software and transformed into data, according to the appropriate decoding algorithm relevant to the symbology being read.
The advantages of the bar codes are speed and accuracy. These are internationally standardized and can store great amounts of information. Capturing data automatically by reading a bar code can be done in fraction of a second, much faster than manual key entry. Reading bar codes makes data capture almost error free. The error rate depends on the type of bar code and equipment being used but it is usually lower than one error per 1,00,000 readings. They are typically self-checking except interleaved two of five.
The bar code technology has gained wide acceptance in numerous applications. Reading bar codes during the production process can provide greater batch control and compliance with FDA's Good Manufacturing Practices. Encoding the lot number and scanning it at different stages throughout the production, storage, and distribution process enables the manufactures to build a completely accurate, real-time record of inventory and work in process. Scanning lot codes or expiration dates can aid in stock rotation and shipping operations.
Unit-of-use bar codes can be read on the production line or at the point of care. Automated production equipment can read codes and route product to appropriate packaging or testing stations. Quality control and testing data can also be captured automatically and linked to production records. The use of bar codes is rapidly increasing in document management. Documents are either filmed or entered into an electronic imaging system. Automatic data entry can be provided with bar coded documents (i.e., the bar code could contain an invoice a number of pages, and a page number). Document sorting can also be reduced if a document code is included in the bar code. The use of bar code will ensure that mix-ups with labels, leaflets, cartons, tubes, ampoules, blister foil, vials and other packaging materials do not occur, as well as efficiency improvement.
The growing use of bar code is creating outstanding new revenue producing and cost saving opportunities for the drug distribution channel. Today, virtually all packages, from the smallest units intended for sale to a consumer to the biggest transport units, bear one or several bar codes carrying their identification number and other data relevant to the parties shipping, carrying or receiving goods.
A strategic investment in high performance labeling equipment will enable distributors to offer repackaging services while improving their own inventory control processes. Retail applications include point-of-sale scanning, inventory control, and time and attendance. The popular bar code application in retail is inventory control. Each time an item is scanned, the on-hand inventory count is automatically decremented. At the end of each business day, a report is generated listing all items, which have fallen below the re-order level. A portable data entry terminal can be used for scanning the store shelves and back storage room, with the information uploaded to the database residing on the host computer. Bar coding is the key to automated materials management.
The hospital pharmacy is an extensive logistic unit and the use of barcodes can be very profitable. The potential applications in hospital pharmacy include inventory control, verifying the accuracy of dispensing to both inpatients and outpatients, and record keeping for drug product expiration or disposal. All physical movements of drugs can be controlled by the use of bar codes. Every drug has to be confirmed by reading the barcode on the unit-dose cell (or on the package when the unit-dose is not yet barcoded). After approval by the computer the amount to be dispensed is shown on the display. This is repeated for every medication order.
Bar codes have already been applied in some hospitals for coding blood containers, Roentgenogram jackets, medical records, and capital equipment. Bar codes also offer pharmacists the ability to perform in-process dispensing controls that are not practical to perform manually. Scanning medications as they are released can also accurately and automatically update inventory records, which makes reordering easier and helps ensure needed medications are always in stock.
Bar code technology offers health care personnel the opportunity to improve work efficiency and increase the accuracy of data entry into automated systems. Bar coding has the potential to be not only cost-effective but to produce a return on investment. To ensure its success, the bar code on the label should be easily readable, and appropriate policies, procedures, and checks should be in place.
-- The authors are Lecturers at Faculty of Pharmaceutical Sciences, M. D. University, Rohtak , Haryana