product review
Dissolution Systems Manufacturers add automation to ease the burden of mandated testing. James R. Riordon
issolution requirements were first added to U.S. Pharmacopoeia (USP) tablet and capsule monographs in 1970 in response to concerns about drug bioavailability. The tests soon proved to be valuable tools for quality control in drug production as well, and in 1976 USP established a policy favoring dissolution testing specifications for all tablets and capsules. The USP now includes more than 500 monographs that specify dissolution testing for topical applications, suppositories, and transdermal patches, in addition to tablets and capsules. The Food and Drug Administration (FDA) requires that all drugs listed in the USP conform to the standards laid out in their respective monographs. Although dissolution-testing methods have evolved somewhat in the past three decades, in recent years, little has changed in the fundamental design of the USP dissolution apparatuses. The handful of companies that manufacture dissolution testers and systems must comply with a strict set of guidelines when producing devices for standardized USP dissolution test methods. “Twenty years ago,” says Cindy Brown, managing editor of Dissolution Technologies, “there were quality differences between dissolution apparatuses from different manufacturers. But these days, all the de-
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vices I’m familiar with are highly reliable and provide similar performance across the board.” Manufacturers are
now striving to attract customers by providing highly automated dissolution systems and integrated analyses, such
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product review
Table 1. Selected dissolution system manufacturers. Distek 121 North Center Dr. North Brunswick, NJ, 08902-4905 732-422-7585 http://www.distekinc.com
Hanson 9810 Variel Ave. Chatsworth, CA 91311 800-821-8165 http://www.hansonresearch.com
USP Apparatuses: 1, 2, 4, 5, 6
USP Apparatuses: 1, 2, 5, 6
Leap Technologies P.O. Box 969 Carrboro, NC 27510-0969 800-229-8814 http://www.leaptec.com
Logan Instruments 19-C Schoolhouse Rd. Somerset, NJ 08873 732-302-9888 http://www.loganinstruments.com
USP Apparatuses: 1, 2, 4
USP Apparatuses: 1, 2
Sotax 3503 York Rd., Ste. 6 Furlong, PA, 18925-1162 215-794-9204 http://www.sotax.com
VanKel 13000 Weston Parkway Cary, NC 27513-2228 919-677-1108 http://www.vankel.com
USP Apparatuses: 1, 2, 4
USP Apparatuses: 1, 2, 3, 5, 6, 7
1: Rotating basket in hemispherical vessel 2: Stirring paddle in hemispherical vessel 3: Reciprocating cylinder 4: Continuous flow cell 5: Stirring paddle over disk in hemispherical vessel 6: Rotating cylinder in hemispherical vessel 7: Reciprocating holder in cylinder as HPLC and spectrophotometry. Many scientists and technicians still perform dissolution tests manually, extracting samples of dissolution media at specified intervals and later measuring drug concentrations. According to Marvin Delgado of Hanson Research, however, automated testing is rapidly gaining in popularity. Sometimes it’s simply a matter of speeding testing and research, although automation frequently provides more than mere convenience. “Primarily it’s due to the increasing complexity of the drugs,” says Delgado. Fast-dissolving products require sampling at rapid intervals, which is challenging for operators. Tests of less-soluble drugs, on the other hand, may last many hours, taxing the patience of laboratory personnel. “If you want to create a dissolution profile, say for an extended-release product,” Delgado explains, “you
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might want to make six or seven pulls on an 8-h or 24-h test.” Clearly, such sampling schedules are ideally suited to automated testing. All of the representative manufacturers listed in Table 1 offer dissolution systems that are automated to varying degrees. Whereas a basic, manually operated dissolution tester typically costs
