Effects of Enteric-Coated Formulation of Sodium Bicarbonate on Bicarbonate Absorption and Gastrointestinal Discomfort

Abstract

Sodium bicarbonate is used as an ergogenic supplement to enhance people's performances in various exercises. This study aimed to evaluate the effects of intestinal delivery of sodium bicarbonate on bicarbonate absorption and associated side effects in an experimental human trial. After preparing and assessing enteric-coated and uncoated sodium bicarbonate tablet formulations, pharmacokinetic analysis and gastrointestinal symptom tests were performed after oral administration in the human body. The dose required to increase blood bicarbonate concentration over 5 mmol∙L^-1 for the purpose of improving performance during high-intensity exercise was also determined. Enteric-coated tablet formulation protects sodium bicarbonate under acidic conditions and releases bicarbonate in the intestine. Enteric-coated tablet formulation also reduced the oral dose required to achieve a blood bicarbonate concentration over 5 mmol∙L^-1 from 300 mg∙kg^-1 of uncoated tablet formulation to 225 mg∙kg^-1. Gastrointestinal discomfort was significantly decreased for the group given 225 mg∙kg^-1 enteric-coated tablets compared to that given 300 mg∙kg^-1 uncoated tablets. These results suggest that enteric-coated tablet formulation could reduce the oral dose required in order to achieve a blood bicarbonate concentration over 5 mmol∙L^-1 by 25%, from 300 mg∙kg^-1 to 225 mg∙kg^-1, along with its ability to reduce gastrointestinal discomfort associated with the dosage.

Keywords: drug delivery; enteric-coated tablet; oral administration; pharmacokinetics; sports supplement.

Figure 1

Average changes in blood bicarbonate concentrations versus time after oral administration of the following sodium bicarbonate formulations in an experimental human trial: (1) enteric-coated tablets equivalent to 225 mg∙kg⁻¹ of sodium bicarbonate (●); (2) uncoated tablets equivalent to 225 mg∙kg⁻¹ of sodium bicarbonate (○); and (3) uncoated tablets equivalent to 300 mg∙kg⁻¹ of sodium bicarbonate (▼). Dotted line shows 5 mmol∙L⁻¹, a reference considered sufficient to improve performance in high-intensity exercise. Each data point represents the mean ± standard error of the mean of 7–10 participants. *, p < 0.05 and **, p < 0.01 compared to the enteric-coated tablet formulation.

Figure 2

Average individual all-time sum scores for each symptom after oral administration of sodium bicarbonate tablet formulations in the experimental human trial. Each data point represents the mean ± standard error of the mean of 7–10 participants; *, p < 0.05 and **, p < 0.01 compared to the enteric-coated tablet formulation. (StB, stomach bloating; Bel, belching; BU, bowel urgency; SA, stomachache; SC, stomach cramps; Flat, flatulence; Dia, diarrhea; Nau, nausea; Vom, vomiting).

Figure 3

Average individual sum scores at each time point for all symptoms after oral administration of sodium bicarbonate tablet formulations in the experimental human trial. Each data point represents the mean ± standard error of the mean of 7–10 participants; * (p < 0.05) and ** (p < 0.01) compared to the enteric-coated tablet formulation.