Use of refractometers to detect controlled-substance tampering

Area of Science:

• Pharmaceutical Sciences
• Analytical Chemistry

Background:

• Hospital pharmacies require efficient methods to verify the integrity of dispensed controlled substance solutions.
• Current monitoring procedures may be complex or costly, creating a need for simpler alternatives.

Purpose of the Study:

• To evaluate the utility of refractive index measurements using hand-held refractometers for monitoring the integrity of hospital pharmacy controlled substance solutions.
• To determine if refractometry can serve as a simple, cost-effective method for quality control.

Main Methods:

• Four hand-held refractometers were employed to measure the refractive index and % Brix of various controlled substance solutions.
• Solutions included fentanyl citrate, morphine sulfate, hydromorphone hydrochloride, and meperidine hydrochloride.
• A survey of 83 returned controlled-substance solutions was conducted using the refractometric method.

Main Results:

• Hand-held refractometers yielded precise and reproducible readings with minimal variability.
• The refractometric method successfully identified a solution with an unexpected concentration among 83 tested solutions.
• While not directly measuring drug concentration, the method poses a barrier to undetected tampering.

Conclusions:

• Refractometry offers a rapid, simple, inexpensive, and reproducible technique for monitoring the integrity of a wide range of drug solutions.
• This method is suitable for routine use in hospital pharmacies to enhance the security of controlled substances.
• The refractometric procedure can serve as a valuable tool for quality assurance in pharmaceutical dispensing.