Potentiometric Determination of the Antacid in the Tablets
Equipment
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0233.100 combined pH glass electrode; input 1
6.1110.100 T sensor
Reagents
c(HCl) = 1.0 mol/L; D0
Sample
25 mL dist. water
1 drop c(NaOH) = 0.1 mol/L
0.268 g Antacid Trigastril (or 0.2-0.4 g)
Remarks
Method to determine the efficiency of tablets against an excess of acid in the stomach. Use a TIP method for the determination: The pH is adjusted to 3 with a pretitration (AntacPre), then the sample is added and the pH kept at 3 during 30 minutes (AntacDet). The determination is carried out in a thermostated titration vessel (e.g.6.1418.220) at 37 °C. You may have to adjust the control parameters of the submethod “AntacDet“ according to your sample. The given parameters are optimized for products which release their base slowly (rate app. 100 L/min).
Calculations:
Acid cap=C70*C01/C00;3;mmol/g
acid cap = acid capacity in mmol/g
C01 = concentration of titrating agent (1 mol/L)
Answer
Acid cap = 3.218 x 1 /0.268 = 12.008 mmol/g
C00= 0.268
C01= 1
C70= 3.218
Sample preparation:
Pulverize the tablet and weigh it exactly. Rinse the powder with 20 mL of pretitrated solution (pH=3) into the titration vessel during the request “Add smpl & start“ and titrate immediately.
Literature
N.J. Kerkhoff et al., Journal of Pharmaceutical Sciences, 66, 1528-1535 (1977)
Method documentation
'pa
751 GPD Titrino 15215 751.0010
TIP… Antacid
parameters
>sequence
1.stirrer:… ON
2.method: …AntacPre
3.info Add… smpl & start
4.method:…. AntacDet
>statistic
status: …OFF
>preselections
req.ident:… OFF
req.smpl size:… OFF
meas.mode: …T
temperature …25.0 °C
------------
'fm
751 GPD Titrino 15215 751.0010
TIP Antacid
>calculations
acid cap=C70*C01/C00;3;mmol/g
C00= 0.268
C01= 1
C70= 3.218
------------
'fr
751 GPD Titrino 15215 751.0010
TIP…. Antacid
smpl size… 0.268 g id#1 Trigast.
C70 ….3.218
acid cap….. 12.008 mmol/g
TIP terminated
============
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