Magnitude of Fruit Juice–Drug Interactions Due to Osmolality-Dependent Fluid Secretion: Differences among Apple, Orange, and Grapefruit Juices

Abstract

We recently reported that the gastrointestinal (GI) fluid volume is influenced by the solution osmolality, and proposed that this effect may play a role in beverage–drug interactions. Here, we investigated whether osmolality-dependent fluid secretion can explain the difference in the magnitudes of fruit juice–drug interactions depending on the type of fruit juice (grapefruit juice (GFJ), orange juice (OJ), and apple juice (AJ)). The osmolality of GFJ, OJ, and AJ used in this study was found to be 552, 686, and 749 mOsm/kg, respectively. Measurements of intestinal fluid movement following beverage administration by the in situ closed-loop technique revealed the following rank order for fluid volume in rat ileum: AJ > OJ > GFJ > purified water, suggesting that water movement is dependent on the osmolality of these beverages. Such changes in GI fluid volume are expected to alter the luminal drug concentration, potentially contributing to the magnitude of beverage–drug interactions. Indeed, in vivo pharmacokinetic study in rats revealed that the plasma concentration of atenolol, a low-permeability drug, was the highest after oral administration in purified water, followed by GFJ and OJ, and was the lowest after administration in AJ. In contrast, antipyrine, a high-permeability drug, showed no significant difference in plasma concentration after administration in purified water and fruit juices, suggesting that the absorption of high-permeability drugs is less affected by solution osmolality. Our findings indicate that differences in the magnitude of beverage–drug interactions can be at least partly explained by differences in the osmolality of the beverages ingested.

INTRODUCTION

Drug interactions with ingested beverages such as fruit juices (FJs) sometimes affect the efficacy and safety of drugs through changes in their gastrointestinal (GI) absorption. For example, it is reported that the plasma concentrations of CYP3A substrate drugs are increased by concomitant ingestion of grapefruit juice (GFJ) due to the inhibition of CYP3A-mediated metabolism by components of GFJ.^1,2) On the other hand, coadministration of GFJ has also been reported to decrease the plasma concentrations of some drugs via inhibition of organic anion transporting polypeptide (OATP) 2B1 by GFJ components.^3–6) This type of interaction occurs not only with GFJ, but also with orange juice (OJ) and apple juice (AJ).⁷⁾ For example, the plasma concentrations of drugs such as fexofenadine, celiprolol, and aliskiren are decreased upon coadministration with various FJs as a result of decreased absorption due to OATP2B1 inhibition by the FJ constituents naringin and hesperidin.^5,8,9)

However, reductions in the plasma concentrations of drugs due to coadministration with FJ have also been observed with drugs other than OATP2B1 substrates. For instance, the plasma concentration of atenolol is decreased when the drug is coadministered with AJ or OJ. Interestingly, OJ contains more OATP-inhibitory components than AJ, yet a greater decrease in the plasma concentration of atenolol has been observed with AJ than with OJ.^5,10,11) These findings suggest that a drug interaction mechanism(s) other than inhibition of transporters may be involved in the reduced absorption.

In this context, we have proposed that osmolality-dependent changes in GI fluid volume may indirectly affect the drug absorption process by altering the drug concentration in the GI tract.^12–14) Indeed, we showed that this effect could account for the AJ–atenolol interaction. Specifically, ingestion of AJ leads to fluid secretion into the GI lumen due to the high osmolality of AJ, resulting in a reduction of GI absorption of atenolol owing to its reduced concentration in the GI fluid.^13,15) Therefore, variations in GI fluid secretion depending on the osmolality of ingested FJ might explain the reported phenomenon that the decrease in the plasma concentration of atenolol is greater with coadministration of AJ than with OJ.^10,11)

In the present study, we investigated whether osmolality-dependent fluid secretion into the GI lumen can explain the differences in the magnitude of FJ–drug interactions depending on the type of FJ.

MATERIALS AND METHODS

Materials

Fluorescein isothiocyanate-dextran 4000 (FD-4) and antipyrine were purchased from Sigma-Aldrich Company (St. Louis, MO, U.S.A.). Atenolol was purchased from Wako Pure Chemical Corporation (Osaka, Japan). All FJs (GFJ, OJ, and AJ) (Tropicana™; 100% pure at normal strength) were purchased from a supermarket in Hachioji city, Japan. All other compounds and reagents were obtained from Nacalai Tesque, Inc. (Kyoto, Japan), Wako Pure Chemical Corporation, or Sigma-Aldrich Company.

Animals

Male Wistar rats were purchased from Tokyo Laboratory Animals Science Co., Ltd. (Tokyo, Japan) and NINOX Labo Supply Inc. (Ishikawa, Japan). All animal experimental protocols were reviewed and approved by the Committee of Animal Care and Welfare of Tokyo University of Pharmacy and Life Sciences (Approval Number: P18-29) and Kanazawa University (Approval Number: AP-204199). Male Wistar rats were housed three per cage with free access to commercial chow and tap water and were maintained on a 12 h dark/light cycle (08:00–20:00 light) in an air-conditioned room (temperature, 24.0 ± 1 °C; humidity, 55 ± 5%).

Measurement of Osmolality of Experimental Solutions

Test compounds (FD-4, atenolol or antipyrine) were dissolved in purified water, GFJ, OJ, or AJ. The supernatant was collected after filtration, and the osmolality was measured with a cryoscopic osmometer, OSMOMAT 030-D (Gonotec GmbH, Berlin, Germany).

In Situ Intestinal Closed-Loop Experiment

The in situ rat intestinal closed-loop experiment was carried out as described previously.¹²⁾ Male Wistar rats (7–8 weeks old; 250 ± 20 g body weight) were fasted overnight and anesthetized by intraperitoneal injection of a triple anesthetic combination (medetomidine, midazolam and butorphanol). The abdominal cavity was opened and an intestinal loop (ileum, 10 cm) was made by cannulation into both ends of the ileum with silicone tubing (i.d., 3 mm). It has been reported that the main absorption site for atenolol is the lower small intestine, so the ileum was used in this experiment.¹⁶⁾ The intestinal contents were washed out through the cannulas with saline. Test compounds (FD-4) were dissolved in purified water, GFJ, OJ, or AJ. One mL of FD-4 solution (10 µM) was introduced into the intestinal loop and both ends of the loop were ligated. At the designated times, FD-4 solution in the loop was collected by flushing with air (for measurement of the luminal concentration of FD-4, C_out), and then made up to 10 mL with buffer solution (for measurement of the amount of recovered FD-4, X_out). The volume of luminal fluid (mL) in each segment of intestine was calculated using the following equation:

  

(1)

where V_fluid (mL) is the fluid volume in each segment of intestine, C_out is the luminal concentration of FD-4 (µM), and X_out is the amount of recovered FD-4 (µmol). The fraction absorbed of FD-4 was calculated from the remaining amount of test compound in each intestinal loop. The values were normalized by the surface area calculated from the radius and length of the small intestine. A radius of 0.178 cm was used for the small intestine.¹⁷⁾

In Vivo Pharmacokinetic Study in Rats

An in vivo pharmacokinetic study in rats was carried out as described previously.¹³⁾ Male Wistar rats (7–8 weeks old; 250 ± 20 g body weight) were fasted overnight and anesthetized by intraperitoneal injection of a triple anesthetic combination (medetomidine, midazolam and butorphanol). Prior to administration of atenolol, the right jugular vein was cannulated with silicone tubing (100-00N; 0.5 mm I.D., 1.0 mm O.D., Kaneka Medical Products, Tokyo, Japan). Rats were orally administered atenolol (1, 0.25 mg/mL) solution or antipyrine (0.1, 0.025 mg/mL) in purified water, GFJ, OJ, or AJ by gavage. The rats could move freely and were not anesthetized during the experiment. Blood samples (500 µL) were collected from the cannula into heparinized tubes at designated times. Each blood sample was replaced with an equal volume of saline and heparinized saline was used to maintain the patency of the catheter. Blood samples were centrifuged at 3000 rpm for 10 min.

Plasma concentration–time curves of atenolol or antipyrine were plotted and analyzed. The pharmacokinetic parameters of atenolol or antipyrine after oral administration were estimated by means of non-compartmental analysis using the MOMENT program.¹⁸⁾ The area under the plasma concentration–time curve (AUC) values of atenolol from 0 to 9 h (AUC_0–9) and antipyrine from 0 to 7 h (AUC_0–7) and from 0 to infinity (AUC_0–∞) were calculated using the linear trapezoidal rule. The maximum plasma concentration (C_max) and the time to reach maximum plasma concentration (t_max) were obtained directly from the experimental data. The apparent elimination half-life of the log-linear phase (t_1/2) was calculated based on the terminal elimination rate constant determined by log-linear regression of the final data points (at least 3).

Analytical Methods

Concentrations of FD-4 were measured with a microplate fluorescence reader (VarioskanTM Flash 2.4; Thermo Fisher Scientific Inc., Kanagawa, Japan) at excitation/emission wavelengths of 492/515 nm.

Atenolol and antipyrine were quantified with an LC-MS/MS system consisting of an MDS-Sciex API 3200™ triple quadrupole mass spectrometer (AB SCIEX, Foster City, CA, U.S.A.) coupled with a LC-20AD ultra-fast LC (UFLC) system (Shimadzu Company, Kyoto, Japan). For atenolol, an Agilent Eclipse plus (C₁₈, 50 × 2.1 mm, 5 µm; Agilent Technologies, Inc., Santa Clara, CA, U.S.A.) was used as the analytical column. Gradient elution was performed with a mobile phase composed of 0.1% formic acid (A) and acetonitrile (B) at a flow rate of 0.4 mL/min. The gradient profile for atenolol was 2% B for 0–1.5 min, 2.0–80% B for 1.5–2.0 min, 80% B for 2.0–4.5 min, 80–50% B for 4.5–5.0 min, 50% B for 5.0–6.0 min, 50–2.0% B for 6.0–6.5 min, and 2% B for 6.5–7.0 min. The total run time was 7.0 min. The mass transitions (Q1/Q3) of m/z 267.2/145.2 and 260.1/116.2 were used for atenolol and propranolol (internal standard), respectively. Analyst software version 1.4.2 (AB SCIEX) was used for data manipulation.

For antipyrine, an Agilent Eclipse plus (C₁₈, 50 × 2.1 mm, 5 µm; Agilent Technologies) was used as the analytical column. Gradient elution was performed with a mobile phase composed of 0.1% formic acid (A) and acetonitrile (B) at a flow rate of 0.4 mL/min. The gradient profile for antipyrine was 5% B for 0–1.5 min, 5.0–90% B for 1.5–2.0 min, 80% B for 2.0–4.5 min, 90–50% B for 4.5–5.0 min, 50% B for 5.0–6.0 min, 50–5.0% B for 6.0–6.5 min, and 5% B for 6.5–8.0 min. The total run time was 8.0 min. The mass transitions (Q1/Q3) of m/z 189.1/56.0 and 260.1/116.2 were used for antipyrine and propranolol (internal standard), respectively. Analyst software version 1.4.2 (AB SCIEX) was used for data manipulation.

Statistical Analysis

Data are given as the mean of values obtained in at least three experiments with the standard error of the mean (S.E.M.). The statistical significance of differences for multiple comparisons was evaluated using one-way ANOVA, followed by Dunnett’s test. A probability of less than 0.05 (p < 0.05) was considered statistically significant.

RESULTS

Measurement of the Osmolality in Various Fruit Juices

The osmolality of each FJ used in this study was measured. The osmolality of GFJ, OJ, and AJ was found to be 552 ± 18, 686 ± 1, and 749 ± 20 mOsm/kg, respectively. All these values are markedly higher than that of isotonic fluid, implying that these FJs are hyperosmotic solutions.

Measurement of the Concentration of Sugars in Various Fruit Juices

The concentration of glucose, fructose, and sucrose in each FJ used in this study was measured. The concentrations of glucose, fructose, and sucrose in the GFJ were found to be 114 ± 21, 102 ± 22, and 26 ± 5 mM, respectively. The concentration of glucose, fructose, and sucrose in the OJ was 96 ± 10, 86 ± 12, and 101 ± 2 mM, respectively, and the concentration of glucose, fructose, and sucrose in the AJ was 133 ± 4, 250 ± 10, and 39 ± 14 mM, respectively.

Effect of Fruit Juices with Different Osmolality on Time Course of Remaining Fraction of Fluid in Rat Intestine

To monitor the effect of FJs with different osmolality on intestinal fluid movement, we examined the variability of luminal fluid dynamics in the rat ileum by employing an in situ intestinal closed-loop technique using FD-4 as an un-absorbable marker (Fig. 1).

Fig. 1. Influence of Osmolality of Fruit Juices on the Time Course of the Remaining Fraction of Fluid in Rat Small Intestine

The remaining fraction of fluid in the ileum was determined by means of the in situ closed-loop method using FD-4 (10 µM, 1 mL) in purified water (open circles), GFJ (closed squares), OJ (closed triangles), or AJ (closed circles) at 10, 30, and 60 min at 37 °C. The horizontal dotted line represents the initial fluid volume (1 mL). Data are means ± S.E.M. (n = 6–9).

The remaining fractions of fluid at 60 min after administration of purified water, AJ, OJ, and GFJ were 63.9 ± 6.4, 166 ± 7, 126 ± 5, and 108 ± 4%, respectively. After administration of purified water, the luminal fluid volume decreased rapidly, but significant water secretion was observed after administration of FJ. Fluid volume after administration of OJ and AJ was increased, whereas there was no change in fluid volume after GFJ administration at 60 min.

Influence of Fruit Juices with Different Osmolality on Intestinal Concentration of FD-4 in Rat Intestine

To examine the possibility that changes in the luminal fluid volume due to the osmotic environment in the GI tract affect the luminal drug concentration, the concentration of FD-4 in the ileum was measured at 30 min after administration of FJs, by means of in situ rat intestinal closed-loop experiments (Fig. 2). The luminal concentration of FD-4 at 30 min after injection of purified water, GFJ, OJ, and AJ was 14.3 ± 0.2, 9.1 ± 0.6, 7.1 ± 0.3, 5.8 ± 0.1 µM, respectively. The intestinal concentration of FD-4 after administration with purified water was higher than the administered concentration (10 µM), whereas the concentration of FD-4 after administration with AJ and OJ was lower than the initial concentration. No significant change in FD-4 concentration was observed after administration with GFJ. These findings suggest that the osmolality-dependent change in the luminal concentration of FD-4 is due to concentration or dilution of FD-4 by fluid absorption or secretion, respectively.

Fig. 2. Influence of Osmolality of Fruit Juices on the Luminal Concentration of FD-4 in Rat Small Intestine

The ileal concentrations of FD-4 after administration in various solutions (purified water, GFJ, OJ, and AJ) was measured by means of the in situ closed-loop method for 30 min at 37 °C. The horizontal dotted line represents the initial dosing concentration (10 µM). The statistical significance of differences between the different conditions was evaluated using one-way ANOVA followed by Dunnett’s test. * p < 0.05, ** p < 0.01, significantly different from purified water. Data are shown as means ± S.E.M. (n = 6–9).

Effect of Fruit Juices on Oral Pharmacokinetic Profiles of Atenolol and Antipyrine in Rats

The mean plasma concentration-time profiles of atenolol (1 mg/kg) in rats were determined after oral administration with purified water, GFJ, OJ, and AJ (Fig. 3). The pharmacokinetic parameters were calculated by non-compartmental analysis and are summarized in Table 1. The AUC_0-9 and the C_max of atenolol after administration with purified water were 233 ± 22 ng·h/mL and 64.3 ± 8.9 ng/mL, respectively. When atenolol was coadministered with GFJ, OJ, and AJ, the AUC_0–9 significantly decreased to 89.2, 68.7, and 62.7%, respectively, and the C_max also decreased to 90.0, 76.7, and 54.7%, respectively. In contrast, coadministration of GFJ, OJ, and AJ did not significantly affect the t_max or the t_1/2 of atenolol.

Fig. 3. Effect of Fruit Juices on Plasma Concentration–Time Profiles of Atenolol in Rats after Oral Administration

Atenolol (1, 0.25 mg/mL) was orally administered with purified water (open circles), GFJ (closed squares), OJ (closed triangles), or AJ (closed circles). Data are shown as the means ± standard deviation (S.D.) (n = 6).

Table 1. Pharmacokinetic Parameters of Atenolol after Oral Administration in Rats

Pharmacokinetic parametersa)	Purified water	GFJ	OJ	AJ
AUC0–9 (ng·h/mL)	233 ± 22	208 ± 36	160 ± 27**	146 ± 19**
AUCR (%)	100	89.2	68.7	62.7
AUC0–∞ (ng·h/mL)	260 ± 33	250 ± 67	179 ± 27**	177 ± 24**
Cmax (ng/mL)	64.3 ± 8.9	58.1 ± 9.8	49.3 ± 11.8**	35.2 ± 4.6**
CmaxR (%)	100	90.3	76.7	54.7
tmax (h)	2.50 ± 0.79	2.67 ± 0.52	2.68 ± 0.52	2.29 ± 0.49
t1/2 (h)	2.75 ± 1.18	3.25 ± 1.27	2.68 ± 1.19	3.62 ± 1.69

Atenolol (1, 0.25 mg/mL) was orally administered with purified water, GFJ, OJ, or AJ. a) AUC, area under plasma concentration-time curve; C_max, maximum plasma concentration; t_max, time to reach maximum plasma concentration; t_1/2, elimination half-life; AUCR, ratio of AUC_0–9 after administration with FJ to AUC_0–9 after administration with purified water; C_maxR, ratio of C_max after administration with FJ to C_max after administration with purified water. The statistical significance of differences between the different conditions was evaluated using one-way ANOVA followed by Dunnett’s test. * p < 0.05, ** p < 0.01, significantly different from purified water values. Data are shown as means ± S.D. (n = 6).

The mean plasma concentration-time profiles of antipyrine (0.1 mg/kg) in rats were determined after oral administration with purified water, GFJ, OJ, or AJ (Fig. 4). The AUC_0-7 and C_max of antipyrine after administration with purified water were 275 ± 69 ng·h/mL and 88.4 ± 21.3 ng/mL, respectively. When antipyrine was coadministered with GFJ, OJ, or AJ, no significant change in the AUC_0–7 or C_max was observed (Table 2).

Fig. 4. Effect of Fruit Juices on Plasma Concentration–Time Profiles of Antipyrine in Rats after Oral Administration

Antipyrine (0.1, 0.025 mg/mL) was orally administered with purified water (open circles), GFJ (closed squares), OJ (closed triangles), or AJ (closed circles). Data are shown as the means ± S.D. (n = 3).

Table 2. Pharmacokinetic Parameters of Antipyrine after Oral Administration in Rats

Pharmacokinetic parametersa)	Purified water	GFJ	OJ	AJ
AUC0–7 (ng·h/mL)	275 ± 69	295 ± 11	283 ± 53	301 ± 27
AUCR (%)	100	107	102	109
AUC0–∞ (ng·h/mL)	311 ± 91	327 ± 19	347 ± 74	344 ± 48
Cmax (ng/mL)	88.4 ± 21.3	92.4 ± 7.9	85.7 ± 16.8	97.6 ± 22.0
CmaxR (%)	100	104	96.0	110
tmax (h)	0.625 ± 0.144	0.583 ± 0.289	0.250 ± 0.0*	0.500 ± 0.250
t1/2 (h)	1.91 ± 0.20	2.03 ± 0.21	2.85 ± 0.45*	2.17 ± 0.44

Antipyrine (0.1, 0.025 mg/mL) was orally administered with purified water, GFJ, OJ, or AJ. a) AUC, area under plasma concentration-time curve; C_max, maximum plasma concentration; t_max, time to reach maximum plasma concentration; t_1/2, elimination half-life; AUCR, ratio of AUC_0–7 after administration with FJ to AUC_0–7 after administration with purified water; C_maxR, ratio of C_max after administration with FJ to C_max after administration with purified water. The statistical significance of differences between the different conditions was evaluated using one-way ANOVA followed by Dunnett’s test. * p < 0.05, significantly different from purified water values. Data are shown as means ± S.D. (n = 3).

DISCUSSION

A decrease in plasma exposure to atenolol was clinically observed when it was taken with AJ, although atenolol is not a substrate of OATP2B1.^10,13) We recently reported that the concomitant ingestion of AJ reduces GI absorption of atenolol due to a decrease in the luminal drug concentration resulting from osmotic fluid secretion into the GI lumen.^13,15) Not only AJ but also OJ has been reported to interact with atenolol absorption, although there are no reports so far examining whether or not GFJ has a clinically relevant effect.^10,11) Since all FJs have high osmolality as described in Results, it seems likely that they decrease the GI absorption of atenolol via the same mechanism as AJ (i.e., osmolality-dependent fluid secretion). However, the magnitude of the interaction may differ among the juices because differences in osmolality are likely to have a direct effect on the magnitude of fluid secretion. In the present study, we investigated whether osmolality-dependent fluid secretion can explain the differences in the magnitude of FJ–drug interactions depending on the type of juice (GFJ, OJ, and AJ).

We first examined whether hypertonicity of FJ causes fluid fluctuations in the GI tract. As shown in Fig. 1, rapid water absorption was observed when purified water was administered. In contrast, significant fluid secretion was observed when OJ and AJ were administered, though GFJ maintained the initial volume at 60 min after administration. Overall, the rank order for remaining fluid volume in rat ileum was AJ > OJ > GFJ > purified water, consistent with the order of osmolality (see Results). Such changes in GI fluid volume may alter the GI drug concentration, which would likely contribute at least in part to the differences in the magnitude of the beverage–drug interactions. Indeed, measurement of the luminal FD-4 concentrations indicated that the variation in fluid behavior in the lumen depending on solution osmolality does affect the drug concentration (Fig. 2). In other words, when purified water was administered, an increase in luminal FD-4 concentration was seen as a result of water absorption, whereas when FJ was administered, a decrease in FD-4 concentration was observed due to dilution based on fluid secretion, which was apparently dependent on the osmolality of the FJ. Furthermore, consistent with these phenomena, in vivo pharmacokinetic studies in rats showed that plasma concentration of atenolol after oral administration was the highest with purified water, followed by GFJ and OJ, and was the lowest with AJ (Fig. 3). Therefore, these findings demonstrate that differences in the osmolality of concomitantly administered beverages affect, at least in part, the magnitude of the beverage–drug interaction.

On the other hand, the reduction in plasma drug concentration due to FJ ingestion observed in in vivo experiments appears to be greater than the effect expected from water secretion observed in in situ experiments. These inconsistent findings may be due to the feature of the in situ closed-loop method, which can exclude the influence of physiological secretions other than water and their GI transit processes. For example, the influence of various types of fluid secretions, including salivary and gastric secretions and subsequent gastric emptying as well as biliary and pancreatic secretions, is very important in considering osmolality-dependent variations in GI fluid volume, each may be involved in osmotic regulation. The concentration of bile acids in the distal small intestine of fasting rats has been reported to be 102 mM, suggesting that the osmotic effect (drug dilution due to water secretion) caused by bile acids is not significant.¹⁹⁾ However, when the effects of other secretions are included, the possibility of a greater impact cannot be ruled out. Further studies would be needed to consider the effects of physiological secretions and their GI transit processes on osmolality-related beverage–drug interactions.

Interestingly, however, GFJ did not reduce the plasma concentration of atenolol, despite its high osmolality of 552 ± 18 mOsm/kg (Fig. 3). This may be due to absorption of the osmotic components of GFJ, such as glucose, fructose, and other sugars, resulting in a decrease in the osmolality of the lumen. This consideration is supported by a recent clinical study using magnetic resonance imaging (MRI), which showed that the fluid volume in the small intestine varies depending on the type of sugar that constitutes the osmolality.²⁰⁾ Briefly, GFJ and glucose and fructose solutions (both adjusted to the same calorie content as GFJ) are compared, showing that differences in sugar absorption may alter the magnitude of fluid secretion into the small intestinal lumen. It is noteworthy that the concentration of glucose (114 mM), fructose (102 mM), and sucrose (a disaccharide combining glucose and fructose) (26 mM) in the GFJ used in this study was similar to the composition of the GFJ used in the clinical study. Therefore, it is plausible that the hyperosmotic environment in the lumen after GFJ administration was attenuated by absorption of sugars, so that the effect of GFJ was insufficient to influence drug absorption. At present, there are no reports yet on the presence or absence of clinical interactions between atenolol and GFJ. However, based on the present results and discussion, no significant interaction is expected to occur between them. It is unclear whether GFJ affects intestinal absorption of other drugs, but we believe that GFJ is less likely to cause osmolality-based drug interactions than other FJs. On the other hand, attenuation of the luminal hyperosmotic environment due to absorption of sugars should still occur after administration of OJ or AJ. Orange juice and AJ used in this study contain higher concentrations of sucrose and fructose, respectively, compared to GFJ (see Results). These findings were consistent with the previous report.²⁰⁾ Since fructose is a poorly permeable substance, the luminal hypertonicity after administration of OJ and AJ may be relatively maintained, resulting in significant drug interactions with OJ and AJ.^21,22) In addition, OJ and AJ have been known to contain pectin, a water-soluble dietary fiber, which is an indigestible heteropolysaccharide with a high molecular weight. The presence of these poorly permeable substances may be a key factor in the magnitude of FJ–drug interactions due to osmolality-dependent fluid secretion. Indeed, in Fig. 3, a decrease in plasma concentration of atenolol was observed after administration with OJ or AJ, and its magnitude is consistent with the initial osmolality of OJ or AJ. Further studies would be needed to clarify the effect of sugar absorption on beverage–drug interaction via the osmotic effect.

It has been reported that GFJ does interact with OATP2B1, which can lead to decreased drug absorption, and in particular, the inhibitory activity of GFJ towards OATP2B1 has been shown to be greater than that of OJ or AJ.⁵⁾ For example, the OATP2B1 substrate fexofenadine has been clinically reported to interact with a variety of FJs, and the mechanism was proposed to be inhibition of OATP2B1.^8,23,24) Nevertheless, the magnitudes of the reduction in the plasma concentration of fexofenadine by coadministration with GFJ, OJ, or AJ are apparently consistent with the rank order of osmolality (lowering effect: AJ > OJ > GFJ), though the difference was not statistically significant.⁸⁾ However, as noted above, GFJ should be less likely to cause osmolality-based drug interactions than OJ or AJ because of the attenuation of the osmotic effect due to absorption of constituent sugars. Therefore, in the case of concomitant use of GFJ, the decreased absorption of OATP2B1 substrate drugs, including fexofenadine, may be primarily due to OATP inhibition rather than osmolality-dependent fluid secretion. Further investigation would be needed to establish the precise contributions of osmolality- and OATP2B1-based mechanisms to drug interaction with FJs.

Using an in situ closed-loop technique, we previously found no significant change in the intestinal absorption of antipyrine when isotonic mannitol solution was simultaneously administered, suggesting that antipyrine absorption is not affected by osmotic pressure.¹²⁾ This can be explained by the rapid absorption of antipyrine, a high-permeability drug, so that variation in fluid dynamics would have little effect on drug concentration or absorption kinetics. Therefore, to understand the relationship between drug permeability and solution osmolality, we also examined the effect of hyperosmotic FJs on intestinal absorption of antipyrine (Fig. 4). No significant change was observed in the plasma concentration of antipyrine after oral administration with any of the FJs compared to purified water. A recent report demonstrated that the high-permeability drugs antipyrine and metoprolol are rapidly absorbed from the upper GI tract, and more than 90% of both were absorbed when they passed through the upper jejunum.¹⁶⁾ In contrast, atenolol, a low permeability drug, was only 20% absorbed when it passed through the upper jejunum. Therefore, it is considered that absorption of antipyrine is complete before drug dilution by fluid secretion. In other words, antipyrine absorption is more rapid than water secretion, suggesting that it may be less sensitive to water secretion due to hyperosmolality. On the other hand, a recent report indicated that sodium/glucose co-transporter 1 (SGLT1) is involved in the solvent drag effect, which transports glucose and water simultaneously.²⁵⁾ Thus, in the case of a hyperosmotic solution composed of glucose, such as FJs, it is possible that simultaneous absorption of glucose and water via SGLT1 may attenuate the degree of osmotic-induced water secretion. Furthermore, in the case of small-molecule drugs such as antipyrine (MW = 188.23), their absorption may be enhanced by a solvent drag effect via the SGLT1 or paracellular pathway, thus contributing to the lack of interaction between FJ and antipyrine. At present, there are many unknowns regarding solvent drag effects, and the relationship with osmotic-induced water dynamics seems quite complex. Further studies would be needed to clarify these effects on beverage–drug interactions. Overall, we consider that drugs with low permeability (e.g., atenolol) have the potential to interact with concomitantly administered beverages, depending on the osmolality of the beverages, whereas drugs with high permeability (e.g., antipyrine) may not interact, regardless of the osmolality. Further studies on the relationship between drug permeability and solution osmolality may be warranted.

In conclusion, our findings indicate that osmolality-dependent changes in GI fluid volume result in changes in the luminal concentration of drugs, thereby potentially altering the absorption characteristics of the drugs, especially those with low permeability. These results suggest that the osmolality of beverages such as FJs that are ingested concomitantly with drugs may be one of the factors in the magnitude of beverage–drug interactions. However, no direct evidence for a quantitative effect of osmolality on GI fluid dynamics in humans has been obtained from this study. Further studies are needed to investigate the direct relationship between osmolality and water movement.

Acknowledgments

This work was supported in part by a Grant-in-Aid for Scientific Research (C) from the Japan Society for the Promotion of Science (JSPS) [20K07165], a Research Grant from Nakatomi Foundation, and a Grant from The Research Foundation for Pharmaceutical Sciences. This work was also supported by a Grant-in-Aid for JSPS Research Fellow (DC1) from the JSPS [21J21599].

Conflict of Interest

The authors declare no conflict of interest.

REFERENCES

• 1) Bailey DG, Spence JD, Munoz C, Arnold JMO. Interaction of citrus juices with felodipine and nifedipine. Lancet, 337, 268–269 (1991).
• 2) He K, Iyer KR, Hayes RN, Sinz MW, Woolf TF, Hollenberg PF. Inactivation of cytochrome P450 3A4 by bergamottin, a component of grapefruit juice. Chem. Res. Toxicol., 11, 252–259 (1998).
• 3) Shirasaka Y, Li Y, Shibue Y, Kuraoka E, Spahn-Langguth H, Kato Y, Langguth P, Tamai I. Concentration-dependent effect of naringin on intestinal absorption of β1-adrenoceptor antagonist talinolol mediated by p-glycoprotein and organic anion transporting polypeptide (oatp). Pharm. Res., 26, 560–567 (2009).
• 4) Shirasaka Y, Kuraoka E, Spahn-Langguth H, Nakanishi T, Langguth P, Tamai I. Species difference in the effect of grapefruit juice on intestinal absorption of talinolol between human and rat. J. Pharmacol. Exp. Ther., 332, 181–189 (2010).
• 5) Shirasaka Y, Shichiri M, Mori T, Nakanishi T, Tamai I. Major active components in grapefruit, orange, and apple juices responsible for OATP2B1-mediated drug interactions. J. Pharm. Sci., 102, 280–288 (2013).
• 6) Shirasaka Y, Mori T, Murata Y, Nakanishi T, Tamai I. Substrate- and dose-dependent drug interactions with grapefruit juice caused by multiple binding sites on OATP2B1. Pharm. Res., 31, 2035–2043 (2014).
• 7) Chen M, Zhou SY, Fabriaga E, Zhang PH, Zhou Q. Food-drug interactions precipitated by fruit juices other than grapefruit juice: an update review. J. Food Drug Anal., 26 (2S), S61–S71 (2018).
• 8) Dresser GK, Bailey DG, Leake BF, Schwarz UI, Dawson PA, Freeman DJ, Kim RB. Fruit juices inhibit organic anion transporting polypeptide-mediated drug uptake to decrease the oral availability of fexofenadine. Clin. Pharmacol. Ther., 71, 11–20 (2002).
• 9) Yu J, Zhou Z, Tay-Sontheimer J, Levy RH, Ragueneau-Majlessi I. Intestinal drug interactions mediated by OATPs: a systematic review of preclinical and clinical findings. J. Pharm. Sci., 106, 2312–2325 (2017).
• 10) Jeon H, Jang IJ, Lee S, Ohashi K, Kotegawa T, Ieiri I, Cho JY, Yoon SH, Shin SG, Yu KS, Lim KS. Apple juice greatly reduces systemic exposure to atenolol. Br. J. Clin. Pharmacol., 75, 172–179 (2013).
• 11) Lilja JJ, Raaska K, Neuvonen PJ. Effects of orange juice on the pharmacokinetics of atenolol. Eur. J. Clin. Pharmacol., 61, 337–340 (2005).
• 12) Ichijo K, Oda R, Ishihara M, Okada R, Moteki Y, Funai Y, Horiuchi T, Kishimoto H, Shirasaka Y, Inoue K. Osmolality of orally administered solutions influences luminal water volume and drug absorption in intestine. J. Pharm. Sci., 106, 2889–2894 (2017).
• 13) Funai Y, Shirasaka Y, Ishihara M, Takemura M, Ichijo K, Kishimoto H, Inoue K. Effect of osmolality on the pharmacokinetic interaction between apple juice and atenolol in rats. Drug Metab. Dispos., 47, 386–391 (2019).
• 14) Takemura M, Tanaka Y, Inoue K, Tamai I, Shirasaka Y. Influence of osmolality on gastrointestinal fluid volume and drug absorption: potential impact on oral salt supplementation. J. Pharm. Heal. Care Sci, 7, 29 (2021).
• 15) Funai Y, Takemura M, Inoue K, Shirasaka Y. Effect of ingested fluid volume and solution osmolality on intestinal drug absorption: impact on drug interaction with beverages. Eur. J. Pharm. Sci., 172, 106136 (2022).
• 16) Masaoka Y, Tanaka Y, Kataoka M, Sakuma S, Yamashita S. Site of drug absorption after oral administration: assessment of membrane permeability and luminal concentration of drugs in each segment of gastrointestinal tract. Eur. J. Pharm. Sci., 29, 240–250 (2006).
• 17) Fagerholm U, Lindahl A, Lennernäs H. Regional intestinal permeability in rats of compounds with different physicochemical properties and transport mechanisms. J. Pharm. Pharmacol., 49, 687–690 (1997).
• 18) Yamaoka K, Nakagawa T, Uno T. Statistical moments in pharmacokinetics. J. Pharmacokinet. Biopharm., 6, 547–558 (1978).
• 19) Christfort JF, Strindberg S, Plum J, Hall-Andersen J, Janfelt C, Nielsen LH, Müllertz A. Developing a predictive in vitro dissolution model based on gastrointestinal fluid characterisation in rats. Eur. J. Pharm. Biopharm., 142, 307–314 (2019).
• 20) Grimm M, Koziolek M, Saleh M, Schneider F, Garbacz G, Kühn JP, Weitschies W. Gastric emptying and small bowel water content after administration of grapefruit juice compared to water and isocaloric solutions of glucose and fructose: a four-way crossover MRI pilot study in healthy subjects. Mol. Pharm., 15, 548–559 (2018).
• 21) Murray K, Wilkinson-Smith V, Hoad C, Costigan C, Cox E, Lam C, Marciani L, Gowland P, Spiller RC. Differential effects of FODMAPs (Fermentable Oligo-, Di-, Mono-Saccharides and Polyols) on small and large intestinal contents in healthy subjects shown by MRI. Am. J. Gastroenterol., 109, 110–119 (2014).
• 22) Ferraris RP, Choe JY, Patel CR. Intestinal absorption of fructose. Annu. Rev. Nutr., 38, 41–67 (2018).
• 23) Imanaga J, Kotegawa T, Imai H, Tsutsumi K, Yoshizato T, Ohyama T, Shirasaka Y, Tamai I, Tateishi T, Ohashi K. The effects of the SLCO2B1 c.1457C > T polymorphism and apple juice on the pharmacokinetics of fexofenadine and midazolam in humans. Pharmacogenet. Genomics, 21, 84–93 (2011).
• 24) Medwid S, Li MMJ, Knauer MJ, Lin K, Mansell SE, Schmerk CL, Zhu C, Griffin KE, Yousif MD, Dresser GK, Schwarz UI, Kim RB, Tirona RG. Fexofenadine and rosuvastatin pharmacokinetics in mice with targeted disruption of organic anion transporting polypeptide 2b1. Drug Metab. Dispos., 47, 832–842 (2019).
• 25) Erokhova L, Horner A, Ollinger N, Siligan C, Pohl P. The sodium glucose cotransporter SGLT1 is an extremely efficient facilitator of passive water transport. J. Biol. Chem., 291, 9712–9720 (2016).