Discussion of Back Titration Report
Discussion
The acid neutralising capacity (ANC) of 3 brands of calcium carbonate (CaCO3) tablets was determined by reacting the tablets in excess standardized hydrochloric acid (HCl) and then back-titrating with a standardized sodium hydroxide (NaOH) solution. Back titration was required for two reasons. Firstly, CaCO3 tablets are poorly water-soluble but dissolve rapidly in acid. Secondly, CaCO3 is a weak base so it is difficult to determine the end point of the reaction if titrated directly.
Assuming good manufacturing practice, the amount of active ingredient described on the product label should conform to quality control standards and accurately reflect the experimentally determined content of CaCO3 in each tablet. Titralac antacid had a measured mass of 0.4031g and this was determined to be 96% accurate based on the labelled mass. Quick-eze antacid had reasonable quality control with a measured mass of 0. 7491g, this being 93.6% accurate based on the label. Tums displayed lower quality control as the antacid had a measured mass of 0.7491g, which was only 84.1% accurate compared to the labelled mass. Overall, tablet quality control appeared high for Titralac and Quick-eze but was lower for Tums. The poor quality control results for Tums is not consistent with a Canadian study of antacids, which found a similar ANC for Titralac (8.5 vs 8.1 mmol HCl), but a higher ANC for Tums (10.5 vs 8.4 mmol HCl ) (Marcra et al CAN med Assoc March 1985) This may indicate an anomalous result.
Utilising the back titration the percentage of CaCO3, the active ingredient, in the tablets could be determined. Consistent with the hypothesis for the experiment the ANC of the tablet increased with increasing active ingredient. Quick-eze neutralised the most HCl, 15mmol, and contained the most active ingredient, 750mg ± 13mg of CaCO3. Tums was ranked second, neutralising 8.4mmol of HCl and containing 420mg ±18mg of CaCO3. Titralac neutralised the least HCl, 8.1mmol, and contained
The acid neutralising capacity (ANC) of 3 brands of calcium carbonate (CaCO3) tablets was determined by reacting the tablets in excess standardized hydrochloric acid (HCl) and then back-titrating with a standardized sodium hydroxide (NaOH) solution. Back titration was required for two reasons. Firstly, CaCO3 tablets are poorly water-soluble but dissolve rapidly in acid. Secondly, CaCO3 is a weak base so it is difficult to determine the end point of the reaction if titrated directly.
Assuming good manufacturing practice, the amount of active ingredient described on the product label should conform to quality control standards and accurately reflect the experimentally determined content of CaCO3 in each tablet. Titralac antacid had a measured mass of 0.4031g and this was determined to be 96% accurate based on the labelled mass. Quick-eze antacid had reasonable quality control with a measured mass of 0. 7491g, this being 93.6% accurate based on the label. Tums displayed lower quality control as the antacid had a measured mass of 0.7491g, which was only 84.1% accurate compared to the labelled mass. Overall, tablet quality control appeared high for Titralac and Quick-eze but was lower for Tums. The poor quality control results for Tums is not consistent with a Canadian study of antacids, which found a similar ANC for Titralac (8.5 vs 8.1 mmol HCl), but a higher ANC for Tums (10.5 vs 8.4 mmol HCl ) (Marcra et al CAN med Assoc March 1985) This may indicate an anomalous result.
Utilising the back titration the percentage of CaCO3, the active ingredient, in the tablets could be determined. Consistent with the hypothesis for the experiment the ANC of the tablet increased with increasing active ingredient. Quick-eze neutralised the most HCl, 15mmol, and contained the most active ingredient, 750mg ± 13mg of CaCO3. Tums was ranked second, neutralising 8.4mmol of HCl and containing 420mg ±18mg of CaCO3. Titralac neutralised the least HCl, 8.1mmol, and contained