Proton Pump Inhibitors Do Not Affect the Bioavailability of a Novel Liquid Formulation of Levothyroxine

OBJECTIVE

This study evaluates the impact of a representative proton pump inhibitor (PPI) (omeprazole), administered simultaneously or staggered, on the pharmacokinetics of levothyroxine (LT4) solution (Tirosint-SOL).

METHODS

This was a randomized, 3-way crossover, comparative bioavailability study in 36 healthy adults under fasting conditions. Omeprazole 40 mg delayed-release capsule was administered once daily from Day 1 to 6 (mornings, Treatment-A; evenings, Treatment-B; none, Treatment-C) to increase and stabilize gastric pH. In the morning of Day 5, a single dose of LT4 solution 600 mcg was administered. Blood samples were collected 0 to 48 hours post-LT4 administration. Noncompartmental pharmacokinetic parameters were calculated for total serum thyroxine using baseline-corrected data. Maximum concentration (Cmax) and area under the concentration-time curve (AUC0-48) were included in an analysis of variance to obtain geometric mean ratios and 90% confidence intervals.

RESULTS

For both comparisons (A/C and B/C), geometric mean ratios and 90% confidence intervals for all parameters were within the equivalence boundaries (80%-125%), indicating bioequivalence: for A/C, AUC0-48 98.98% [94%-104%], and Cmax 91.68% [87%-97%]; for B/C, AUC0-48 98.94% [95%-103%], and Cmax 94.90% [90%-100%]. Median Tmax (time associated with Cmax) was similar across treatments.

CONCLUSION

This study demonstrated that Tirosint-SOL bioavailability is unaffected by coadministration of a representative PPI, given simultaneously or staggered by about 12 hours, compared to administration of LT4 solution alone. For hypothyroid patients on PPI therapy, administration of LT4 solution may reduce variations in thyroid stimulating hormone levels related to intermittent use of acid-reducing drugs and consequently the need for dose adjustments.

Efficacy of Levothyroxine Sodium Soft Gelatin Capsules in Thyroidectomized Patients Taking Proton Pump Inhibitors: An Open-Label Study

Background: Treatment with proton pump inhibitors (PPIs) and antacids affects the gastrointestinal absorption of levothyroxine sodium (LT4) tablets. Patients with hypothyroidism taking LT4 and PPIs or antacids, thus, require appropriate monitoring. The objective of this study was to determine whether a soft gelatin capsule of LT4 (Tirosint®) would obviate the effect of PPIs on LT4 absorption. The objective was achieved by assessing the effects of a switch from a conventional LT4 tablet form to the same dose as soft capsules in thyroidectomized patients on treatment with LT4 and PPIs. Methods: Patients with history of hypothyroidism due to total thyroidectomy on stable treatment with LT4 tablets, and with gastrointestinal disease treated with PPIs, were switched to a 12-week treatment with Tirosint at the same dose of the LT4 tablets, while maintaining treatment with PPIs. Serum thyrotropin (TSH) levels were the primary endpoint of the study. Secondary efficacy endpoints were: serum levels of free thyroxine (fT4), total thyroxine (TT4), free triiodothyronine (fT3), total triiodothyronine (TT3), creatine-phosphokinase (CPK), sex-hormone binding globulin, ferritin, angiotensin converting enzyme, and a lipid panel. Results: Forty-seven patients (36 females and 11 males, mean age 55.4 years) were enrolled and 45 of them completed the study (2 patients withdrew consent). During treatment with Tirosint, mean TSH levels demonstrated a statistically significant decrease (mean changes from baseline: -0.32 mIU/L at week 6 and -0.68 mIU/L at week 12) and concomitant increases in thyroid hormone (TH) levels from baseline to week 12, which were statistically significant for fT3 and TT3 (mean changes from baseline: 0.26 pmol/L and 0.10 nmol/L, respectively). Significant decreases of serum low-density lipoprotein, total cholesterol, and CPK levels were observed at week 12. No signs/symptoms arose during the study that could be specifically correlated to either hypo- or hyperthyroidism. Conclusions: In thyroidectomized patients taking PPIs and replacement LT4, a switch from conventional LT4 tablets to LT4 soft capsules at the same dose was associated with a significant decrease in TSH and increase in TH, indicating that LT4 absorption may be less affected by PPIs when given in the form of soft capsules. Clinical Trial Registration: NCT03094416.

RF23 | PSAT365 An Open-Label Therapeutic Efficacy Study of Tirosint (Levothyroxine Sodium) Capsules in Thyroidectomized Patients Taking Proton Pump Inhibitors

Levothyroxine sodium (LT4) absorption is known to be affected by proton pump inhibitors (PPIs). Normal gastric acid secretion is important for the subsequent intestinal absorption of LT4. A reduced gastric acidity may diminish the dissolution of the LT4 tablet in the stomach and the release of LT4 to the gut. The dissolution profile of LT4 soft capsules has been reported to be less affected by pH than that of tablets. Previous studies in healthy subjects administered with LT4 and PPIs, as well as in hypothyroid patients with atrophic gastritis confirmed little or no impact of increased gastric pH on LT4 absorption when administered in soft capsule formulation. The present study was aimed at evaluating whether LT4 soft capsules may provide better control of thyroid stimulating hormone (TSH) in thyroidectomized patients undergoing chronic replacement therapy with LT4, who were also on chronic use of PPIs.Forty-seven (47) patients were enrolled in this multicenter study. Upon switching to Tirosint capsules at the same previous dose of LT4 tablets and while maintaining the same dose of PPI, TSH (when measured on week 12 of treatment) was significantly reduced from a mean±SD of 1.34±1.51 mIU/L to 0.75±1.08 mIU/L (p<0.0001) in the Intention-To-Treat population analysis on original data. No significant changes were detected in the level of free and total thyroxine (T4), while slight but significant (p<0.05) increases were measured in free and total triiodothyronine (T3). The measured extent of TSH decrease is consonant with the extent of TSH increase previously reported by other authors upon start of PPI therapy in hypothyroid patients treated with LT4 tablets.In conclusion, these data confirm previous reports that LT4 soft capsules absorption is not affected by increased gastric pH due to PPIs. This may be relevant to improve TSH stabilization in patients who take PPIs intermittently or those with gastric pH altered by concomitant pathologies.

Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m., Sunday, June 12, 2022 1:00 p.m. - 1:05 p.m.

A Novel Levothyroxine Solution Results in Similar Bioavailability Whether Taken 30 or Just 15 Minutes Before a High-Fat High-Calorie Meal

Background: Levothyroxine (LT4) sodium is a standard treatment for hypothyroidism. Its absorption and bioavailability when taken as a tablet have been shown to be significantly decreased with concomitant food ingestion. Therefore, LT4 formulations are recommended to be taken on an empty stomach, at least 30, ideally 60, minutes before breakfast, potentially affecting adherence to therapy. A novel LT4 solution (Tirosint^®-SOL) has been shown to result in a faster absorption process than tablets or soft-gel capsule formulations. The objective of this trial was to evaluate the bioavailability of this preparation taken 15 minutes before a high-fat high-calorie meal in comparison with the minimally recommended 30-minute interval. Methods: Thirty-six (33 completers, 24 males and 9 females) healthy volunteers participating in the randomized study took 600 mcg of LT4 oral solution, single doses after a 10-hour fast, 15 or 30 minutes before a high-fat, high-calorie, FDA-approved standardized meal in a controlled research setting. We measured serum total thyroxine using Liquid Chromatography with Tandem Mass Spectrometry at baseline and multiple time points up to 72 hours after LT4 administration. The predefined equivalence boundaries for the extent of exposure reflected by the area under the curve (AUC) were 80-125%. The washout period was at least 35 days. Results: The geometric mean ratios and confidence intervals (CIs) for the baseline-adjusted extent of exposure represented by AUCs truncated at both 48 and 72 hours after dosing (AUC_0-48: 90% [90% CI 86-94]; and AUC_0-72: 92% [90% CI 87-97]) were within the prespecified equivalence boundaries. The baseline-adjusted peak concentration was also clinically similar (C_max: 85% [90% CI 80-90]). The median t_max was 1.5 hours in each group. The rate of adverse events was similar between groups. Conclusions: We observed no significant difference in the pharmacokinetic properties of a novel LT4 solution administered 15 and 30 minutes before a high-fat high-calorie meal in normal subjects. Further research is needed to evaluate (a) the differences in overall bioavailability at other time points (including immediately premeal) and (b) the real-world effectiveness of this preparation in newly proposed administration conditions to optimize treatment outcomes in hypothyroid patients.

Pharmacokinetics and Comparative Bioavailability of a Levothyroxine Sodium Oral Solution and Soft Capsule

A new formulation of levothyroxine sodium has been developed in the form of an oral solution contained in unit‐dose ampules. A study has been conducted to compare the bioavailability of levothyroxine sodium oral solution and levothyroxine sodium soft capsule in healthy volunteers under fasting conditions. The rate and extent of absorption of the new levothyroxine solution were also evaluated when administered on dilution in water or directly into the mouth without water. In each period, according to the randomization scheme, subjects were administered single oral doses of either test, as 4 × 150‐μg unit‐dose ampules, with or without water, or reference, as 4 × 150‐μg capsules in a crossover design. Thirty‐six subjects were randomized and dosed in this study; of these, 31 completed all study periods. When comparing the solution with the capsule (both products administered with water), the 90% confidence intervals for the ratio of log‐transformed values of AUC_0‐48 and C_max were within 90.00% and 111.11%, respectively, for baseline‐corrected levothyroxine. Moreover, the administration of levothyroxine oral solution without water did not affect the rate and extent of its absorption. In conclusion, levothyroxine oral solution unit‐dose ampules were bioequivalent to the levothyroxine capsule when administered with or without water. All formulations were well tolerated, with no major side effects.

When Bioequivalence in Healthy Volunteers May not Translate to Bioequivalence in Patients: Differential Effects of Increased Gastric pH on the Pharmacokinetics of Levothyroxine Capsules and Tablets

PURPOSE

Clinical studies have suggested that proton pump inhibitors may decrease levothyroxine absorption and an in vitro study suggested that the effect of pH on dissolution may differ with formulation. To determine the impact of formulation on the pharmacokinetics of levothyroxine in altered gastric pH conditions, this study compared the pharmacokinetics of levothyroxine capsules and tablets, two formulations deemed bioequivalent in healthy volunteers under fasting conditions, when taken with or without esomeprazole.

METHODS

Two clinical studies were conducted in healthy volunteers given single dose levothyroxine (600 mg) with a 45-day washout period. In Study 1 (parallel-design/two-way crossover), 16 subjects received either levothyroxine capsules or tablets, each group with or without prior administration of intravenous esomeprazole (maximum dose of 80 mg). In Study 2 (two-way crossover), 16 subjects received both capsules or tablets after intravenous esomeprazole. Blood samples were collected pre-dose and up to 24 hours post-dose. Baseline-adjusted pharmacokinetic parameters were calculated: Cmax (maximal concentration), Tmax (time to Cmax), AUC0-t (area under the concentration-time curve from 0 to the last detectable concentration), AUC0-6 and AUC0-12 (areas under the curve from 0 to 6 and 12 hours, respectively). Analyses of variance were conducted to compare ln-transformed Cmax and AUC. Non-parametric Tmax analyses were done.

RESULTS

In Study 1, esomeprazole caused a greater decrease in overall levothyroxine exposure of tablets vs. capsules (13% vs 6% for Cmax, 18% vs. 14% for AUC(0-6), 17% vs. 5% for AUC(0-12) and 10% vs. 8% for AUC(0-t)). In Study 2 esomeprazole administration resulted in a 16% smaller levothyroxine exposure with tablets vs. capsules. No statistically significant differences in Tmax were found.

CONCLUSIONS

Although both formulations are considered "bioequivalent" in healthy volunteers, they may not necessarily be bioequivalent in patients with impaired gastric pH conditions. Levothyroxine capsules may therefore be more appropriate for patients with decreased gastric acidity.

The free fractions of circulating docosahexaenoic acid and eicosapentenoic acid as optimal end-point of measure in bioavailability studies on n-3 fatty acids

The high complexity of n-3 fatty acids absorption process, along with the huge amount of endogenous fraction, makes bioavailability studies with these agents very challenging and deserving special consideration. In this paper we report the results of a bioequivalence study between a new formulation of EPA+DHA ethyl esters developed by IBSA Institut Biochimique and reference medicinal product present on the Italian market. Bioequivalence was demonstrated according to the criteria established by the EMA Guideline on the Investigation of Bioequivalence. We found that the free fractions represent a better and more sensitive end-point for bioequivalence investigations on n-3 fatty acids, since: (i) the overall and intra-subject variability of PK parameters was markedly lower compared to the same variability calculated on the total DHA and EPA fractions; (ii) the absorption process was completed within 4h, and the whole PK profile could be drawn within 12-15 h from drug administration.

Pharmacodynamics and pharmacokinetics of a novel, low-dose, soft-gel capsule of acetylsalicylic acid in comparison with an oral solution after single-dose administration to healthy volunteers: a phase I, two-way crossover study

BACKGROUND

Low-dose acetylsalicylic acid (ASA; aspirin) is well-established as a platelet anti-aggregating agent for the secondary prevention of cardiovascular events.

OBJECTIVES

The objective of this study was to investigate the non-inferiority of a novel ASA 75 mg soft-gel capsule formulation compared with a marketed powder for oral solution in terms of reduction in serum thromboxane B2 (TXB2), a surrogate for platelet aggregation. Pharmacokinetics and tolerability of the products were also investigated.

METHODS

In this randomised, two-way crossover study, 46 male and female healthy subjects received a single dose of the investigational products in two periods separated by a 14-day washout. Serum TXB2 and plasma ASA were determined up to 24 h post-dose. Maximum percentage of TXB2 inhibition (I max) and area under the inhibition-time curve (AUICt) were calculated. Non-inferiority was assumed if the lower limits of the 95 % confidence intervals (CIs) for the two pharmacodynamic parameters were above 85 %.

RESULTS

The 95 % CI lower limits were 95.35 % for I max and 86.12 % for AUICt, i.e. within the pre-specified delta. Time to achieve I max did not differ between treatments (p = 0.88). The two formulations were bioequivalent as regards the extent of ASA exposure (area under the plasma concentration-time curve from zero to time t [AUCt] 90 % CIs 96.67-113.37); a delayed ASA absorption (later time to reach maximum plasma concentration [t max], lower maximum plasma concentration [C max]) was observed for the test product. No treatment-related adverse events were reported.

CONCLUSIONS

In healthy subjects, the 75 mg soft-gel capsules were not inferior to the oral solution in terms of serum TXB2 inhibition, indicating that the novel formulation could be an effective alternative in the secondary prevention of cardiovascular events.

Pharmacokinetics and potential advantages of a new oral solution of levothyroxine vs. other available dosage forms

To better understand the pharmacokinetics and potential advantages of a levothyroxine oral solution vs. tablets and soft gel capsules.4 randomized, 2-treatment, single-dose (600 mcg levothyroxine), 2-way crossover bioequivalence studies in 84 healthy subjects were analyzed. Samples were collected before dosing and until 48-72 h post-dose to calculate noncompartmental baseline-adjusted pharmacokinetic parameters: maximum concentration, time to maximum concentration, and area-under-the-concentration-time-curve from 0 to 48 h and from 0 to 2 h.Mean pharmacokinetic parameters (±standard deviation) for tablets, capsules and solution, respectively, were: area-under-the-concentration-time-curve from 0 to 2 h (ng*h/mL)=68.4±32.8, 64.4±24.4, 99.1±22.7; area-under-the-concentration-time-curve from 0 to 48 h (ng*h/mL)=1 632±424, 1 752±445, 1 862±439; maximum concentration (ng/mL)=67.6±20.9, 68.0±15.9, 71.4±16.0; time of maximum concentration (hours)=2.25±0.99, 2.38±1.58, 1.96±1.07. Overall rate and extent of exposure were not statistically different between formulations, but a faster onset of absorption for the solution was suggested (greater area-under-the-concentration-time-curve from 0 to 2 h and faster time to maximum concentration by an average of 30 min).Levothyroxine rate and extent of exposure are similar between tested formulations. The solution appears however to reach systemic circulation quicker as dissolution is not needed before absorption starts. The solution's greater early exposure and a faster time to maximal concentration of around 30 min may be of benefit to minimize drug-food interactions and deserves further investigations.

Topical ketoprofen patch in the treatment of tendinitis: a randomized, double blind, placebo controlled study

OBJECTIVE

To evaluate the efficacy and tolerability of ketoprofen patch in the treatment of tendinitis.

METHODS

A multicenter, 14 day, randomized, double blind placebo controlled trial of a once-a-day ketoprofen 100 mg patch in symptomatic tendinitis of recent onset, not requiring orthopedic or surgical treatment. Pain on daily activities scored on a 100 mm visual analog scale was the primary efficacy criterion. Other criteria were spontaneous pain at rest, pain on full passive motion, pain relief, and pain intensity assessed twice daily by the patient (calculation of total pain relief and summed time-weighted pain intensity difference). Statistical analysis was performed on the differences between the 2 groups in the intention-to-treat population.

RESULTS

One hundred seventy-two patients were included. Good compliance was obtained in 98% of patients. Twenty-six patients (15%) discontinued the study mainly because of adverse events, inefficacy, or cure. Decrease in pain after one week of treatment (primary criterion) was -38.4 +/- 25.6 mm (56%) and -25.8 +/- 24.5 mm (37%) in the ketoprofen and placebo groups, respectively (p = 0.0013). The differences of the secondary criteria during the trial between the 2 groups were significant more often than not. Tolerance was considered satisfactory in both groups, most adverse events reported being local reactions: 47 versus 44 were possibly or probably related to treatment in the ketoprofen and placebo groups, respectively. These local skin reactions resolved spontaneously and rarely led to premature termination of treatment.

CONCLUSION

This trial suggested that a 3-14 day course of treatment by ketoprofen patch is useful in nonarticular rheumatisms, the duration of treatment depending on the results obtained. The safety profile revealed no unexpected adverse events.

Topical ketoprofen patch (100 mg) for the treatment of ankle sprain: a randomized, double-blind, placebo-controlled study

BACKGROUND

Topical nonsteroidal anti-inflammatory drugs offer the advantage of enhanced drug delivery to local affected tissues with low plasma levels and an expected reduced incidence of systemic adverse events (mainly peptic ulcer disease and gastrointestinal hemorrhage).

HYPOTHESIS

To test the efficacy and tolerability of a 100-mg patch of ketoprofen applied once a day.

STUDY DESIGN

Randomized controlled clinical trial; Level of evidence, 1.

METHODS

The 2-week trial included patients suffering painful (spontaneous pain >or=50 mm on a 0- to 100-mm visual analog scale), benign (grade I or II), recent (<2 days) ankle sprains as a model of general traumatic soft tissue injuries. The primary efficacy criterion was spontaneous pain change after 7 days of treatment in the intention-to-treat population. One hundred sixty-three patients were randomized (ketoprofen, 81; placebo, 82).

RESULTS

After 1 week of treatment, the decrease in spontaneous pain was -50+/-20 mm for ketoprofen and -38+/-24 mm for the placebo, showing a statistically significant intergroup difference (P=.0007). The majority of the secondary criteria were also statistically significant in favor of the ketoprofen patch. Tolerance was good in both groups, adverse events being mostly local.

CONCLUSION

This trial suggested that a 7-day course of treatment with a ketoprofen patch is useful in benign ankle sprain, without revealing unexpected adverse events.