Generally, class 2 may be used for quantities greater than 20 mg, class 3 for quantities of greater than 50 mg, and class 4 for quantities of greater than 100 mg. This is accomplished by defining and requiring the observance of a minimum weight standard as defined in usp chapter 1251. Chapter 1251 is not binding and contains recommendations to the installation site also proposals. Usp chapter 41 gwp usp general chapter 1251 mettler toledo analytical balance weight selection klaus fritsch weighing on an analytical balance fda usp weighing sops minimum weight balance routine testing. Usp 1251 the concept of minimum weight in order to satisfy the required weighing tolerance, when samples are weighed the amount of sample mass i. The usp now requires a simple test to assess a balances accuracy a balance test weight must not differ by more than 0. Make sure you are compliant with the latest usp guidelines. Jul 23, 20 united states pharmacopeia usp published the revised mandatory chapter 41 on balances in june, as well as new updates to the advisory chapter 1251. In most cases, the minimum amount of specimen, in mg, can be estimated using the formula. Usp chapter 41 has updated their testing requirements to determine the suitability of balances.
A certificate will be automatically generated upon completion of the course, which should take 6090 minutes. The united states pharmacopeia usp is a scientific, non. Usually analytical balance should be used from 50 mg onwards to 80% of the balance higher range. The latest revisions to the united states pharmacopeia usp general chapters balances and weighing on an analytical balance became official on dec. Information about minimum weight you can find here. For other companies around the world, and for other applications or in other segments, a riskbased approach to balance. Repeatability is satisfactory if two times the standard deviation of the weighed value, divided by the desired smallest net weight i. For example, a 100mg check weight might be selected for a balance that has a load limit of 150 mg. Analytical balances and usp interpertation of and has had a lot of people confused. For companies that need to comply with the united states pharmacopeia usp, riskbased testing protocols and scheduled calibrations must be carried out according to chapter 41, with advice given in general chapter 1251. This elearning course provides all the information required to understand the 20 revisions to usp general chapters 41 balances and 1251 weighing on an analytical balance. Estimates of uncertainty of the calibration of balances. The way that this has been explained to me is as minimum weight.
The minimum net sample weight, in short, minimum weight, mmin, of an analytical balance can be expressed by the equation. Minimum weight good weighing practice from mettler toledo. Remove the contents from each container by employing any safe technique e. United states pharmacopeia usp published the revised mandatory chapter 41 on balances in june, as well as new updates to the advisory chapter 1251. The accuracy of a balance is satisfactory if its weighing value, when tested with a suitable weights, is within change to read. From the usp 41 repeatability test i determined an operating range start point of 16. Microbalances proceed as directed for analytical balances, but use a checkweight appropriate for the particular balance. Weighing on an analytical balance 939 log book for comparison with previous readings.
Now in the sepoct 2014 usp pharmacopeial forum for public comment. With decreasing sample size, measurement uncertainty of a weighing instrument increases. In the residual titration, excess reagent is added to the test specimen, sufficient time is allowed for the. In pharmaceutical industry pharmacy risk assessment.
Calculate the min sample weight by using the following formula. Determine the standard deviation from the 10 readings recorded. Monographs for dietary supplements and ingredients appear in a separate section of the usp. It is clearly stated that minimum weight applies to the sample weight, not the tare or gross weight. Here is a quick reference on the important aspects and updates. For example, a 100mg checkweight might be selected for a balance that has a load limit of 150 mg. The united states pharmacopeia usp was created nearly 200 years ago, dedicated to instilling trust where it matters most. Where is the limit of your weighing system that still allows you to weigh accurately. Thoroughly cleanse and dry the outsides of the containers by suitable means, and weigh individually. Method ib residual titration principlesee the information given in the section principle under method ia. Uncertainity fails for 20 mg weight using analytical balance. But according to usp weights and balances, a simple theoretical calculation can be used to calculate the minimum weight for any balance. A collection of tools relating to the usp general chapters 41 and 1251 and the extensive updates made to these chapters in 20. As repeatability fluctuates over time, when possible, weighing should be performed at larger values than the minimum weight safety factor.
For the calculation of the drift 10 mg weight shall be used. It uses the analysis of a composite from multiple units. Minimum weight good weighing practice from mettler. May 15, 2015 usp chapter 41 has updated their testing requirements to determine the suitability of balances. Usp chapter 41 does not reference minimum sample weight any longer, rather it defines repeatability and accuracy, which is of crucial importance to determine the operating range of a balance.
Weighing on an analytical balance general information usp 35. A test weight is suitable if it has a mass between 5% and 100% of the balances capacity. Weights should be calibrated periodically, preferably against an absolute standard weight. Minimum weight in order to satisfy the required weighing tolerance, when samples are weighed the amount of sample mass i. The calculation allows you to determine the balance measurement uncertainty of the balance and by using a correlation curve this can then help you to determine to minimum weight which can be accurately measured on a balance. To weigh a sample of 50mg, one might assume that a balance with a readability of 0. Usp chapters 41 and 1251 on weighing mettler toledo. It is recommended to only weigh net samples that weigh sufficiently more than the minimum weight to. Feb 19, 2014 the latest revisions to the united states pharmacopeia usp general chapters balances and weighing on an analytical balance became official on dec. In neither of these tests is there a requirement that individual results conform to the assay. Note down the 10 measurements of the 10 mg weight in the performance check log. Oteelectronic balndeviation greater than those indicated below for anaances operate on a load cell principle that produces an lytical balances and microbalances is observed, the bal electrical output.
Check that the indicator value is zero, place calibration weight w2 at the center of the pan, and then. Based on the process need derived from a riskbasedapproach this balance is only used to weigh between 22 and 52kg. The minimum weight is the least amount of material that can be weighed on an instrument resulting in uncertainty that is not greater than the required tolerance. On 3 june 20, the united states pharmacopeia usp published the revised mandatory chapter 41 on balances as well as new updates to the advisory chapter 1251. Compared to the minimum weight as an annex to the dakks calibration, the minimum weight is only repeatability considered according to usp. The new revisions define modified balance test procedures for the us pharmaceutical industry and also apply to companies exporting to the us. General chapters 41 balances and 1251 weighing on an analytical. Ciprofloxacin is only indicated in infections caused by susceptible bacteria. As in step 1, load calibration weight w2, and then record indicator value i2. A minimum weight is determined by dividing the standard deviation of the repeatability r std of the balance by the required accuracy. Acceptance limits for analytical balances iso 17025.
Chromatography is defined as a procedure by which solutes are separated by a dynamic differential migration process in a system consisting of two or more phases, one of which moves continuously in a given direction and in which the individual substances exhibit different mobilities by reason of differences in adsorption, partition, solubility, vapor pressure, molecular size, or ionic charge. Procedure weigh accurately 1 to 2 g of the substance, or the amount specified in the individual monograph, in a suitable crucible silica, platinum, quartz, or porcelain that previously has been ignited at 600 50 for 30 minutes, cooled in a desiccator silica gel or other suitable desiccant, and weighed. Uspnf sf in which s is the volume, in ml, of the reagent consumed in the second titration. The united states pharmacopeia usp is the american counterpart to the german pharmacopeia and is used by many companies in germany as a guideline. Perform one measurement using a test weight with a mass between 5% to 100% of the balances capacity. A weight class is chosen so that the tolerance of the weights used does not exceed 0. How do the new published revisions for usp general. The usp clearly defines when class 1, class 2 and class 3 weights should be used. Have you heard about the new usp chapter 41 changes. Mettler toledos gwp weighing standard ensures usp compliance. Weighing standard ensures usp compliance pharmaceutical. A new method for calculating minimum weight is given with the standard deviation, s, derived by using a test weight up to a few percent of the balance capacity.
The usp describes the quality of the weights to be used for this test. However, they have only a slight impact with small weights. Generally, class 2 may be used for quantities category product description. There are two required tests in chapter 41, accuracy and repeatability. Usp chapter 41 now defines that weighing shall be performed using a balance that is calibrated over the operating range and meets the requirements defined for repeatability and accuracy. According to usp general chapter balances, for substances to be accurately weighed, the balance used must be calibrated over the operating range and meet the following requirements defined for repeatability and accuracy.
Moisten the sample with a small amount usually 1 ml of sulfuric acid. Monographs for drug substances, dosage forms, and compounded preparations are featured in the usp. Load weight t1 as the tare load weight, and then take tare. The calibration applies for the current ambient temperature. This approach specifies an absolute minimum, which is a positive addition. It is important to note that while this particular guideline is only relevant for pharmaceutical laboratories which must be in compliance with usp standards.
The operator must know the maximum capacity of the balance to select the correct check weight. Check that the indicator value is zero, place calibration weight w2 at the center of the pan, and then record the indicator value i3. The quality standards we develop help manufacturers deliver on their promises of safe products, while building confidence among healthcare. C is the used volume, in percent, of the capacity of the buret. L6469,l6472,l6475,l6478,l6481,l6484,l6487,l6490,l6493 ciprofloxacin immediate release tablets, oral suspensions, and intravenous injections are indicated for the treatment of skin and skin structure infections, bone and joint infections, complicated intraabdominal. In the pharmaceutical industry, the united states pharmacopoeia usp set of standards for managing balances is widely recognized around the world. The interpretation of usp has had a lot of people confused. It shall be performed as per the manufacturers instructions. During most processes intended for formula elaborating, mass measurement should be performed.
Uspnf is a combination of two compendia, the united states pharmacopeia usp and the national formulary nf. Usp standards state that a balance must have a repeatability that is equal to or less than 0. Procedure to calibrate the analytical weighing balance as drift check, performance check and measurement uncertainty check as per usp. The types of chromatography useful in qualitative and quantitative analysis that are employed in the usp procedures are column, gas, paper, thinlayer, including highperformance thinlayer chromatography, and pressurized liquid chromatography commonly called highpressure or highperformance liquid chromatography. Weighing on an calibration system based on an applied load. With just six months to comply, mettler toledo says its global weighing standard, gwp, can help pharmaceutical manufacturers and suppliers to meet the new requirements. Chapter 41 is a requirement for qc analysis measurements. It shows that if you have a balance with least count 0. These revisions aim to ensure weighing accuracy and eliminate unnecessary overtesting for us pharmaceutical manufacturers and suppliers. Weighing standard ensures usp compliance epm magazine. Fcvkf in which f is the water equivalency factor of the reagent, in mg per ml. The weighing quality significantly influences the quality of final result.
Furthermore as balance performance can change over time as a result of environmental changes etc. Checks can be partially replaced using automatic or manually triggered adjustment by means of builtin weight. Jun 17, 2018 the minimum net sample weight, in short, minimum weight, mmin, of an analytical balance can be expressed by the equation. According to usp chapter 1251, we can find this value by multiplying the standard deviation by the coverage factor and dividing by the required tolerance. Usp packaging storage and distribution expert committee.
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