Volume 10, Issue 2

Agilent PracticalSolutionsNewsletter

The USP Performance Verification Test (PVT) criteria were significantly altered with the new lot of prednisone tablets, P1I300, released on March 1, 2010. This lot of tablets, which is a continuation of lot P0E203 (1), has different acceptance criteria based on a separate collaborative study to address accuracy and precision, as well as minor modifications to the recommended testing criteria. The new criteria call for both a whole-assembly geometric mean to be within a range and a %CV to be met in order to pass on a given apparatus. Also, the new testing criteria offer options for both single- and dual-stage testing.

The purpose of the new specifications is to account for variability of the dissolution apparatus, which a range alone is not able to do. Variability can come from a number of sources including the dissolution apparatus, the accessories, the analyst, and laboratory environment. It can be difficult to determine which of these plays a role in a failing run, and after a failure, all of these variables should be evaluated for potential impact on the dissolution test.

Critical Path for PVT SuccessIn This Issue:The Disintegration Apparatus 2

TruAlign Dissolution Vessel 3

Dissolution Workstation Software 4

Agilent 8453 Online UV Multicomponent Dissolution 5

Dissolution and Vibration 6

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Agilent validation chemists perform the PVT test on all brands of dissolution apparatus. As a result, we see a broad spectrum of results and, where necessary, perform failure investigations in order to understand the root cause. Our application engineers coach individuals requiring assistance with the PVT and have found that the areas most correlated to dissolution failure with lot P1I300 are: vessel geometry, centering, improper deaeration, improper sampling and filtration, stirring vessels prior to starting the dissolution test, rough or inaccurate pouring of media, maintenance issues, and paddle/basket condition.

VesselsVessels have been the single largest cause of failures with the PVT. Vessel-related failures are correlated to the use of different vessel types on a single system, use of poorly manufactured economy vessels, misalignment within the system, and scratched or dirty vessels.

Use of mixed and/or economy vessels is correlated to a higher coefficient of variation (%CV) and failure rates. The reason for this is that consistency of vessel geometry is key to producing reproducible hydrodynamics in each vessel, which is required for reproducible dissolution results. While the vast majority of vessels available in the market meet USP <711>, the spec for vessels is very wide allowing different manufacturers to create vessels in very different ways. When these vessels are mixed, they often have different volumes under the paddle or basket due to the relationship of height, diameter, and curvature from one vessel to another and yield different results. Economy vessels tend not to have the same level of quality found in vessels direct from the apparatus manufacturers, and will show a wider %CV as well.

Scratched and dirty vessels can also cause issues with altered hydrodynamics and adsorption of drug onto the vessel.

CenteringCentering plays an important role in maintaining hydrodynamics in the vessel; therefore, centering devices must be in

good condition. For dissolution apparatus with EaseAlign centering rings, all of the “fingers” on the ring must be intact and the O-rings within the EaseAlign ring must fit tightly on the pegs in the vessel plate. This will ensure proper centering of the vessel, as well as maintain vessel verticality and prevent vessel movement during a run. To avoid variability, use only Agilent centering rings as replacements.

EaseAlign centering ring systems can also be upgraded with TruCenter conversion kits, which have shown reduction in variability due to superior centering and verticality. The 708-DS, Agilent’s newest dissolution apparatus, features TruAlign vessels, which specifically address centering and verticality and have shown similar, if not improved, results to the TruCenter vessels.

DeaerationDeaeration continues to be a key parameter, as it has been with previous prednisone lots due to the sensitivity of prednisone. Mix of passive and active. Change to: The USP degassing procedure outlined in <711> and the PVT Technical Data sheet, or a validated alternative, should be used. If using helium sparging or an automated media preparation station, the dissolved gas level should be cross-checked with a dissolved gas meter to show <6 ppm. Helium sparging is the second most common degassing practice in the industry, and it has been successful with the current lot of prednisone tablets when used properly. Helium sparging must be validated against the USP degassing procedure to ensure it is acceptable for prednisone testing.

Care should also be taken in pouring of the media once degassed. Media should be poured gently to prevent reaeration. The best practice would be to weigh media directly into the vessel so that there is only one pouring step – and better volume accuracy is gained as well, which can reduce %CV. Remember that volumetric glassware may only be used at the temperature at which it was calibrated and graduated cylinders may not meet ± 1.0% volumetric accuracy required by USP.

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Conformance to compendia specifications has and remains our top priority. The International Conference on Harmonisation (ICH), which harmonized the EP, USP and JP, altered the disintegration apparatus with changes that may require customers to review their procedures to ensure compliance with the harmonized disintegration chapter found in USP 34 <701> Disintegration. Although the procedures have changed slightly, the Agilent 100 Disintegration Apparatus remains unchanged since it is already compliant with the new harmonized procedure.

So what does this really mean? Your Agilent 100 still meets either specification for the beaker dimensions and the disintegration fluid volume is not stated in USP <701> Disintegration. Although many procedures may state that 900 mL should be used for disintegration, this is not a compendia requirement. The basket hanger and beaker volume may easily be adapted to meet these criteria.

The Agilent 100 is available in two configurations, either a single-basket model or the more versatile three-basket unit. This self-contained system includes an integrated water bath and circulator, and the drive mechanism for the basket assemblies is enclosed in the body of the instrument.

The Disintegration Apparatus

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Agilent 100 Automated Disintegration Apparatus

Critical Path: continued

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The ultimate goal of any dissolution test is to determine the rate of release of an active component into solution and, possibly, detect batch or formulation differences. As evidenced by recently published materials from regulatory agencies, it is becoming increasingly important to control the physical parameters, accessories, and techniques related to the dissolution environment. One critical component that plays a significant role in determining dissolution results is the vessel – and Agilent’s TruAlign vessel provides a quality solution.

The TruAlign vessel, the standard vessel used with the 708-DS Dissolution Apparatus, serves to precisely align the dissolution vessel every time. Once installed in the vessel plate, the amount of possible movement is negligible and borderline detectable. This enables the vessel to maintain accurate center and verticality alignment with respect to the dissolution apparatus. Each TruAlign vessel is fitted with a collar incorporated onto the vessel rim to protect the vessel and facilitate safe handling. The collar also

includes a helpful indicator tab that allows for reproducible vessel orientation each time the vessel is installed.

The USP Performance Verification Test (PVT) and ASTM and FDA Mechanical Qualification (MQ) procedures both rely on quality vessels for acceptable results. The design, manufacturing, and consistency of the TruAlign vessel have been shown to provide a reduced Coefficient of Variation (%CV) during the USP PVT for paddle and basket tests. When verifying physical parameters as part of the MQ, the stability of the vessel ensures repeatable centering and vessel verticality values. In both cases, the indicator tab can be used to ensure the same vessel orientation upon insertion.

The combination of the TruAlign vessel and the 708-DS give the dissolution analyst a clear advantage for achieving proper results.

See the difference in the quality and reliability of Agilent’s newest vessels and dissolution apparatus.

Agilent’s TruAlign Dissolution Vessel – When Quality Counts

Link to online store: www.agilent.com/lifesciences/vessel_ordering

The Disintegration Apparatus

Most laboratories performing dissolution testing have procedures in place requiring documentation of each step in the process. This may involve test-specific information about the product and instrument, as well as real-time data for every test. Oftentimes, this information is manually transcribed in separate log books, checklists, etc. One way to simplify this process, increase data integrity, reduce paperwork and become just a bit “greener” is by implementing Agilent’s Dissolution Workstation Software.

The Dissolution Workstation Software provides complete, integrated control of multiple dissolution systems (Agilent, Varian or VanKel) from a single computer. By utilizing this solution in an electronic records environment, several aspects of the dissolution test are documented and controlled for less reliance on manual transcription and improved record-keeping. The software makes it possible to implement the essential requirements necessary for compliance in a 21 CFR Part 11 environment.

Setup and execution of dissolution tests within the Dissolution Workstation Software is a simple 2-step process. Separate files are created and maintained for the system configuration(s) and the method(s). The configuration file contains all relevant apparatus information including serial numbers, accessory

IDs, and specific settings. The method file stores all pertinent test parameters such as sample timepoints, temperature, speed, and volume(s). Each of these files is created upon initial setup of the system. For each subsequent test, it is only necessary to select the appropriate system and method to be executed. An additional screen is made available before starting the test for entering test-specific data, as well as choosing one of the available delayed start options.

Individual user rights and privileges are controlled by the Dissolution Workstation Software through leveraging the security capabilities of the Windows® operating system. Several user groups exist that, depending on the user’s credentials, enable or disable features of the software according to group membership. This allows for a higher-level user to create the system configurations and methods while someone with lower-level rights can simply run the necessary tests with no chance of accidental setup errors. All changes to any file within the software automatically trigger the creation of a new version of that file. The audit trail feature dynamically determines the differences between two or more versions and can display these in a consolidated report.

All results generated with the Dissolution Workstation Software can be previewed, exported, digitally signed, and printed.

The test report includes the method and instrument identification, time/date of test, real-time equipment data, and a complete activity log of all events. The data is stored within a database that may be created locally or on a network. The client-server architecture offers the potential to integrate or export the data to a laboratory information management system (LIMS).

Agilent’s complete line of dissolution equipment is available for use with the Dissolution Workstation Software. This includes all Apparatus 1/2/5/6 models (e.g., 708-DS), Apparatus 3/7 models (e.g., BIO-DIS), and the associated automated sampling equipment. Up to four individual systems – even of different models – may be connected to a centralized PC to perform concurrent dissolution tests.

Now, a solution is available to eliminate the paper trail and streamline dissolution testing in a compliant environment – let the Dissolution Workstation Software work for you.

Dissolution Workstation Software – A “Greener,” Compliant Approach to Dissolution Testing

Method monitoring screen, visible during method setup and testing.

Sample test report generated by the Dissolution Workstation Software

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Dissolution testing is typically quantified with UV and HPLC analytical techniques. While UV is often preferred during analytical development due to its flexibility, simplicity and cost savings, it is traditionally used for single component analysis only. HPLC may be chosen for a variety of reasons including specificity requirements and individual quantitation of multiple active drugs, or the elimination of interferences commonly seen in the UV spectra. However, with modern instrumentation yielding more precise data and modern regression analysis techniques, multiple component online UV dissolution testing becomes feasible. Agilent offers UV multicomponent dissolution analysis through the strong pairing of the Agilent 8453 UV-visible spectrophotometer, 708-DS Dissolution Apparatus and UV-visible ChemStation software.

UV multicomponent dissolution testing provides solutions for obtaining valuable information on multiple compounds in the analytical development phase of dosage forms, and the quality control process as well. With high-quality multicomponent analysis of dissolution samples, determinations can be made quickly, with numerous timepoints, and may reduce the cost of drug development without a loss of analytical integrity.

Real-Time AnalysisA key benefit of real-time analysis may be realized with multiple drug dosages where one or more products undergo

degradation. Online testing may be the preferred route for some products that could potentially decompose over time and require additional handling, preservation, or refrigeration. For these products it is important that measurement be conducted in real time during the dissolution test. Post-run spectroscopic analysis or an even slower HPLC analysis could produce significant bias due to compromised sample integrity. Rapid sampling coupled with fast data acquisition and evaluation makes real-time multicomponent analysis possible.

Simplicity and SpeedSpectroscopic methods of analysis have an advantage of simplicity and speed compared to chromatographic methods. With diode array analysis, dissolution samples may be taken as often as every minute. Numerous data points can be acquired and charting can be completed for critical profile attributes, even for immediate release products. Burst phases may also be adequately captured with multiple data points in the early stages of extended and controlled release of multiple drug products. Analytical R&D areas may benefit from quick turnaround time afforded by online analysis, which yields data at the end of the dissolution test to expedite review, decision making and time to market.

Economic AlternativeMulticomponent dissolution analysis may be viewed as a cost-saving solution compared to the higher cost of

chromatographic separation. Not only are consumable costs kept to a minimum (without HPLC columns, guard columns, mobile phase constituents and disposal costs) but filtration solutions may also be less expensive with full flow filtration rather than the 0.45µ filtration commonly required for HPLC analysis.

Simple CalibrationCalibration is simple and fast using pure standards or mixtures of standards. Statistics for the fit of the standards to the sample spectra give you confidence in your results. With modern instrumentation yielding more precise data and modern regression analysis techniques available within ChemStation, multiple component online UV dissolution testing becomes feasible. The algorithms provided are linear least squares fits and maximum likelihood fits. The maximum likelihood algorithm uses statistical information available for each individual data point in the acquired spectra.

In summary, your ability to perform multicomponent dissolution analysis of known and investigative active drug substances will provide additional data points at critical stages of release without a loss of specificity, accuracy or precision. Simultaneous acquisition, sophisticated regression analysis, excellent wavelength reproducibility, and the ability to obtain instant spectral absorbance data over the entire wavelengths range provide the analyst with a superior tool for dissolution analysis. Please visit the Agilent website or contact us for information pertaining to online multicomponent dissolution analysis.

Agilent 8453 Online UV Multicomponent Dissolution

Multicomponent analysis with diagnostic tools that show the quality of the results.

There has been considerable controversy regarding the qualification of dissolution apparatus since dissolution laboratories are now confronted with two sets of standards concerning the performance qualification of the apparatus; the traditional USP Performance Verification Test (PVT) with prednisone tablets and the new Enhanced Mechanical Calibrations (or Mechanical Qualification, (MQ) standards from FDA and ASTM. The primary focus of both practices is to provide a suitable apparatus and environment conducive to providing accurate results with minimum variability. Each stresses the detection and elimination of accuracy and precision issues arising from the apparatus or its environment to ensure the quality and integrity of dissolution results.

The traditional USP PVT is a holistic method for detecting perturbation within the dissolution apparatus. In the presence of vibration, prednisone release rates may fail the limits for geometric mean or %CV. The USP test is somewhat analogous to the check engine light that may illuminate on your automobile instrument panel when something is wrong. You really don’t know exactly what is wrong, but you need to check it out, isolate the source of the problem and fix it. In this regard, a failed PVT result indicates a problem that needs further investigation for the source of the problem and then a solution implemented, including a corrective action to keep the problem from reoccurring. Vibration may be a difficult issue to diagnose, especially after a dissolution run is complete.

The Enhanced MQ procedures which target individual perturbance are a bit less precise with regard to vibration. Although the original PhRMA studies indicated that

the USP PVT should be maintained until there is a suitable vibration specification, there has not been a suitable vibration measurement, specification or tolerance developed at the time of this writing. The ASTM and FDA procedures, have been acknowledged as suitable alternatives for qualification of the dissolution apparatus by the FDA Guidance for Industry. The Guidance states “that appropriate measures be taken to control the following sources of significant variability in dissolution testing: dissolved gasses, vibration and vessel dimensions.” Although a meaningful vibration tolerance and specification has yet to be developed, an FDA collaborative study, in which Agilent is participating, is working to identify the definitive parameters of vibration and set a specification and tolerance. Since the limit has yet to be determined, the best practice at the time is elimination of sources of vibration which may affect dissolution apparatus.

While there are various means of detecting vibration, including Agilent’s QAII C Mechanical Qualification Station, it is essential that the dissolution environment is free of sources of vibration. This not only reduces the risk of impact on dissolution results which generally may make products dissolve faster, but it increases the reliability of the apparatus to generate results that support the integrity of the performance test. The approach to detecting vibration issues may be slightly different, but the primary goal of providing good results is best accomplished by investigating these three areas:

Location of the Dissolution LaboratoryThe location of the dissolution laboratory is essential for its ability to produce dissolution testing results that are not influenced by vibration. The location surrounding the dissolution laboratory should be free from non-analytical sources of vibration routinely found around and adjacent to the laboratory such as slamming doors, stairwells, elevators, process equipment, and forklift traffic. Dissolution may be greatly affected by sources immediately outside your facility, such as heavy machinery, highway or building construction, railroads, parking decks and garages. Occasionally, dissolution laboratories must be relocated or suspend testing during periods of construction.

Remove all Sources of Vibration Dissolution apparatus are best kept away from other analytical instrumentation and sample preparation equipment. For the same reasons that we isolate balances from vibration, we should use a similar rationale for dissolution apparatus. Immediate sources of vibration typically found in the laboratory are fume hoods, ultrasonic baths, orbital and wrist-action shakers, mixers, centrifuges, vacuum pumps, tapped density equipment and even other analytical equipment such as GCs and HPLCs and certain computers and printers. Agilent qualification chemists have even observed a radio perched on top of a dissolution apparatus playing music with heavy bass, clearly contributing to vibration issues.

Dissolution and VibrationUsing the QAII C, you can take several different measurements, including wobble and RPM measurement (left) and vibration measurement (right).

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QAIIC vibration sensor

Internal Sources of VibrationRegular preventative maintenance procedures should be in place to routinely check for vibration within the dissolution apparatus, including the condition and placement of the heater/circulator. Routine maintenance should include the removal of the top cover to check the belt for performance issues such as missing teeth, belt wear, and a loose belt, pulleys or spindles. A slight dusting of black rubber is common in most apparatus and may not cause a problem unless the belt is exhibiting excessive wear. The heater/circulator should never directly touch the dissolution apparatus unless it features isolators to shield the apparatus from vibration.

In summary, whether a vibration specification is in place or not, the best remedy for eliminating the influence of vibration is to remove all sources of vibration from the dissolution environment. The USP PVT cites the sensitivity of prednisone to several parameters, including vibration, to alert the user that conditions for dissolution testing may be unacceptable. Although existing mechanical qualification parameters and enhanced parameters may be used to tune the apparatus to reduce variability, the analyst is still responsible for addressing issues that are not directly addressed by with the enhanced mechanical qualification procedures, such as the condition of vessels, the presence of vibration and deaeration.

1 ASTM E2503-07, Standard Practice for Qualification of Basket and Paddle Dissolution Apparatus, 2007

2 FDA DPA-LOP.002, Mechanical Qualification of Dissolution Apparatus 1 and 2, Version # 2.0, Effective June 2, 2006

3 FDA Guidance for Industry, The Use of Mechanical Calibration of Dissolution Apparatus 1 and 2 – CGMP, January 2010. www.fda.gov/downloads/Drugs/.../Guidances/UCM198649.pdf

Pre-Harmonization Requirements from USP <701> Disintegration:

“The apparatus consists of a basket-rack assembly, a 1000-mL, low-form beaker, 138 to 155 mm in height and having an inside diameter of 97 to 110 mm for the immersion fluid”

“The volume of the fluid in the vessel is such that at the highest point of the upward stroke the wire mesh remains at least 2.5 cm below the surface of the fluid and descends to not less than 2.5 cm from the bottom of the vessel on the downward stroke.

Post-Harmonization Requirements from USP <701> Disintegration:

“The apparatus consists of a basket-rack assembly, a 1000-mL, low-form beaker, 138 to 160 mm in height and having an inside diameter of 97 to 115 mm for the immersion fluid”

“The volume of the fluid in the vessel is such that at the highest point of the upward stroke the wire mesh remains at least 15 mm below the surface of the fluid and descends to not less than 25 mm from the bottom of the vessel on the downward stroke. At no time should the top of the basket-rack assembly become submerged.”

Both units are microprocessor controlled for setting up a test and leaving it unattended. At the end of the designated testing time, the basket is suspended from the media so you can check for any residual tablet material. The three-basket model allows for three independent tests to be performed simultaneously, as each basket can be independently programmed.

In addition to the standard six-tube basket assembly, we offer three-tube

and single-tube baskets for larger dosage forms such as those required for veterinary products. Agilent also offers disintegration beakers and cylindrical disks required for conformance to compendia specifications, an assortment of mesh screen sizes, and individually measured verified components with NIST-traceable equipment that are documented for conformance verification.

Disintegration Apparatus: continued from p. 2 Dissolution and Vibration: continued from p. 6

Underlined values indicate changes from Pre- to Post-Harmonization Requirements

Disintegration baskets and accessories

Agilent PracticalSolutionsNewsletter

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This information is subject to change without notice.© Agilent Technologies, Inc. 2011Printed in U.S.A., June 20115990-7913EN

Learn more:www.agilent.com/lifesciences/dissolution

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Improper Sampling and FiltrationThe USP sampling zone is the area in the vessel which is the most reproducible and allows for representative sampling. Sampling and filtration of samples needs to occur within a 2% window of a timepoint per USP. Sampling or filtering outside of this window allows dissolution to continue, causing higher and more variable results. We recommend the use of Agilent’s Full Flow Filters, which filter as you are pulling a manual sample and save valuable time compared to using a syringe disk filter. Also, automated sampling should not be used for the PVT, unless it has already been validated. Due to hydrodynamic disturbance created, resident probes should not be used in the qualification procedure.

Tablet PositioningWhen dropped into the vessel, prednisone should settle at the bottom-center of the vessel to ensure proper dissolution. An

off-center landing can often result in the prednisone tablet forming an off-center cone, which then redistributes as a cone in the center of the vessel. Due to the high shear rate just outside the calm center of the vessel the prednisone particles may be rapidly distributed into the media and exhibit a rapid rate of dissolution, usually about 3-5% faster, leading to different results than tablets that initially landed in the center.

To prevent off-center landing, do not stir the vessels for media equilibration at least two minutes prior to the start of the run. Even once the paddles are stopped, the media will continue to rotate and will give a greater chance for the tablet to land off-center.

Critical Path: continued from p. 2

Agilent chemists are always available to assist you with dissolution questions. Should you require assistance with performing and passing the PVT, feel free to contact our Dissolution Hotline at dissolution.hotline@agilent.com.