Here we demonstrate a method to measure the pantoprazole
content in tablets within 10 minutes. There are no reagents
necessary. By using the Photopette® handheld
spectrophotometer [1, 2] only minimal training is requited.
The method is easy and fast performed in two steps 1)
Calibration and 2) Measurement. The method can be
performed at any location and does not require a lab.
Pantoprazole is a medication used for the treatment of
stomach ulcers, short-term treatment of erosive esophagitis
due to gastroesophageal reflux disease, maintenance of
healing of erosive esophagitis, and pathological
hypersecretory conditions. It is available as tablet or injection.
Pantoprazole is a proton pump inhibitor that decreases
gastric acid secretion. It works by inactivating (H+/K+)-
ATPase functioning the stomach. It is available as a generic
medication and on the WHO list of essential medicines [3].
Pantoprazole has very good solubility in water and an
absorbance maxima at 290 nm. The drug can be quantified
at it absorbance maxima or at a wavelength close to it; here
we use 280 nm. We compared the spectrum from pure pantoprazole with pantoprazole extracted from tablets; the spectrum was identical confirming that there are no interfering substances present.
MATERIALS AND APPARATUS:
Instrument:
• Photopette® with 280 nm wavelength
Reagents:
• Pantoprazole standards of 20,40 and 80 mg/L in
water.
Materials:
• 1 liter measurement cylinder (plastic).
• 1 liter bottle (glass or plastic).
• Glass or metal rod (30 cm long).
The method requires an initial calibration using the “Method
Maker” in the Photopette app. This calibration only needs to
be performed once; after, the created method can be called
and measurements are performed on the spot. The initial
calibration needs a Pantoprazole standard solution.
INITIAL CALLIBRATION WITH THE METHOD MAKER
This process is performed in two steps. First, the Photopette’s
normal measurement function is used to generate the
calibration data. Second, the “Method Maker” is opened and
the calibration data is loaded to create the new Method. The
calibration can be performed by using a Pantoprazole
standard from Tip Biosystems Pte Ltd or by using a selfprepared
standard.
Self-preparation of the standard: Weight 80 mg of
pantoprazole and transfer it to a 100 mL glass measurement
flask. Fill up half with water, shake and dissolve the
Pantoprazole. Fill up to the mark. Dilute the standard by 10,
20 and 40 fold to generate calibration solutions of 80, 40 and
20 mg/L.
Generating the calibration data: Connect the Photopette
device to a smart device and open the Photopette App. Klick
on “Measurement type” and select 280 nm. Place a CuveTipÒ
firmly onto the Photopette® device and insert into DI water as
BLANK sample to perform auto-zero. Ensure that there is no
air-bubble trapped in the CuveTipÒ cavity. A guide to use the
CuveTipÒ correct is available as download [2]. Use the same
CuveTipÒ to take 3 more measurements in the water sample
(this is the 0 mg/tablet measurement). Remove any water
trapped in the CuveTip cavity by touching a clean paper wipe.
Take 3 measurements in the standard labelled “20
mg/tablet”, clean the tip and take 3 measurements in the
standard labelled “40 and 80 mg/tablet”. This completed the
data generation.
DETERMINING THE PANTOPRAZOLE CONCENTRATION IN
TABLETS
Sample preparation: Transfer one Pantoprazole tablet in a 1
litre bottle. Use a clean glass or metal rod to crush the tablet
to a powder. Fill 1 litre clean water (DI water if available or
bottled water) into the 1 litre measurement cylinder. Transfer
some water from the measurement cylinder into the bottle
and flush the rod. Remove the rod and transfer the rest of the
water from the cylinder into the bottle. Close the bottle and
gentle shake for 5 min. Let the bottle rest for 5 min to allow
any particles to sediment.
Measurement: Open the Photopette App, connect to the
Photopette device, klick on “Measurement type” and select
“Pantoprazole Measurement”. Click on “Start Measurement”
and follow the instructions.
| Pantoprazole Tablets | Result (mg/tablet) |
| Generic brand A | 44 |
| Generic brand B | 45 |
| Generic brand C | 42 |
Place a CuveTipÒ firmly onto the Photopette® device and
insert into the same water used to dissolve the tablet to
perform Autozero. Measure the Pantoprazole sample
prepared above by using the same CuveTip. The result is
displayed in mg/tablet Pantoprazole with a resolution of 0.1
mg.
Errors
The error of the volume measurement is max 5 mL or less
than 0.5% and therefore negligible. The error of the
photometric measurement is smaller than 0.01 AU or about
1% at an AU corresponding to 40 mg Pantoprazole per tablet.
With the same error made at the calibration, the total error of
the method is smaller than 3% or about plus/minus 1
mg/tablet pantoprazole.
Summary:
With Photopette the concentration of pantoprazole in tablets
can be measured at any location in less than 15 min. Almost
no training is required. The accuracy of +-1 mg/tablet is
sufficient to test drug specifications. Photopette is ideal for
quick checks, troubleshooting and quality control.
Download PDF version of this experiment here
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