Pharmaceutical microemulsion composition of clarithromycin with improved stability, bioavailability and antimicrobial activity against Helicobacter pylori

Abstract

Pharmaceutical microemulsion composition of clarithromycin with improved stability, bioavailability and antimicrobial activity against Helicobacter pylori, comprising: (a) 1 gram of clarithromycin as active pharmaceutical ingredient; (b) 8 grams of an oil phase consisting of a 1:1 mixture of glyceryl tricaprylate and peppermint oil; (c) 40 grams of a surfactant mixture (Smix), the surfactant being Tween 80 and the co-surfactant being Transcutol P, present in a ratio optimized to maintain an isotropic and thermodynamically stable microemulsion; (d) 52 grams of an aqueous phase comprising purified water; wherein the microemulsion composition is characterized by a mean droplet size of less than 30 nanometers, a viscosity in the range of 3.91 to 18.97 centipoise (cps), and a pH in the range of 4.56 to 7.06; and wherein the composition provides improved solubility, bioavailability, and physicochemical stability of clarithromycin under gastric pH conditions, thereby improving therapeutic efficacy against Helicobacter pylori.

Description

[0001] The present invention relates to a composition comprising a clarithromycin-loaded microemulsion with peppermint oil and synergistic essential oils for the treatment of Helicobacter pylori infections.

[0002] The treatment of Helicobacter pylori (H. pylori) infections continues to pose a major challenge due to increasing antibiotic resistance and the poor solubility of these drugs in the stomach. Clarithromycin, an important antibiotic in H. pylori eradication therapy, suffers from reduced efficacy due to its low solubility, poor bioavailability, and susceptibility to degradation in the acidic gastric environment. Conventional oral dosage forms often result in suboptimal drug concentrations at the site of infection, contributing to treatment failure and recurrent infections. Furthermore, patient noncompliance due to side effects such as gastrointestinal disturbances further limits treatment success.

[0003] To overcome these limitations, essential oils such as peppermint oil and other synergistic natural oils have gained attention due to their antimicrobial, anti-inflammatory, and gastroprotective properties. However, their direct use is hampered by their volatility, low water solubility, and inconsistent bioavailability. A microemulsion-based drug delivery system offers a promising approach to overcome these challenges by improving the solubility and stability of clarithromycin while ensuring controlled and targeted drug release. This formulation can enable better penetration into the gastric mucosal layer, effectively reaching H. pylori colonies while reducing systemic side effects.

[0004] The present invention presents a clarithromycin-loaded microemulsion utilizing peppermint oil and synergistic essential oils to enhance therapeutic efficacy against H. pylori. This novel formulation improves drug absorption, stability, and targeted delivery, ensuring higher bacterial eradication rates while minimizing the development of resistance. The use of a microemulsion system provides sustained release, reduces dosing frequency, and improves patient compliance. By integrating natural oils into antibiotic therapy, this invention offers an innovative, effective, and patient-friendly approach to overcoming current limitations in the treatment of H. pylori.

[0005] Another object of the present disclosure is to improve the solubility of clarithromycin to achieve better absorption.

[0006] Another object of the present disclosure is to enhance the efficacy of clarithromycin against H. pylori through the synergistic effect of peppermint oil.

[0007] Another aim of the present disclosure is to reduce the required dosage of clarithromycin and thus minimize possible side effects.

[0008] Another aim of the present disclosure is to reduce the risk of developing antibiotic resistance.

[0009] Another object of the present disclosure is that glyceryl tricaprylate improves the solubility and stability of the formulation.

[0010] A further aim of the present disclosure is to ensure a higher availability of the active ingredient in the gastric region.

[0011] Another object of the present disclosure is to provide extended drug release for improved efficacy.

[0012] A further object of the present disclosure is suitability for large-scale pharmaceutical production.

[0013] Another object of the present disclosure is to provide a convenient, user-friendly dosage form.

[0014] The present invention generally relates to a stable microemulsion composition of clarithromycin utilizing glyceryl tricaprylate and peppermint oil to improve solubility and antimicrobial efficacy.

[0015] One embodiment of the present invention is that the composition has a strong antimicrobial effect against Helicobacter pylori and thus improves the treatment results in gastric infections.

[0016] A further embodiment of the invention is that the microemulsion composition consists of a precise ratio of oil, surfactant (Tween 80, Transcutol P) and aqueous phase to ensure high drug loading and stability.

[0017] A further embodiment of the invention is that the process comprises controlled emulsification, ultrasonic treatment and physico-chemical evaluations to achieve a uniform, effective and reproducible composition.

[0018] Another embodiment of the invention is the pharmaceutical microemulsion composition of clarithromycin with antimicrobial activity against Helicobacter pylori, which comprises: (a) 1 gram of clarithromycin as active pharmaceutical ingredient; (b) 8 grams of an oil phase consisting of a 1:1 mixture of glyceryl tricaprylate and peppermint oil; (c) 40 grams of a surfactant mixture (Smix), the surfactant being Tween 80 and the co-surfactant being Transcutol P, present in a ratio optimized to maintain an isotropic and thermodynamically stable microemulsion; (d) 52 grams of an aqueous phase comprising purified water; wherein the microemulsion composition is characterized by a mean droplet size of less than 30 nanometers, a viscosity in the range of 3.91 to 18.97 centipoise (cps), and a pH in the range of 4.56 to 7.06; and wherein the composition provides improved solubility, bioavailability and physicochemical stability of clarithromycin under gastric pH conditions, thereby improving therapeutic efficacy against Helicobacter pylori.

[0019] The present invention relates to a novel pharmaceutical composition developed for improved antimicrobial activity against Helicobacter pylori. It comprises clarithromycin in an optimized formulation to improve its solubility, bioavailability, and stability. The composition was developed using specific excipients and processing techniques to achieve sustained drug release and ensure a prolonged therapeutic effect. This formulation overcomes the limitations of conventional clarithromycin administration by prolonging its gastric residence time and minimizing side effects. Furthermore, it is designed for ease of manufacture and good patient tolerability, making it a promising advance in the treatment of H. pylori-associated infections. EXAMPLE 1: Composition

[0020] A pharmaceutical microemulsion composition of clarithromycin with antimicrobial activity against Helicobacter pylori, comprising: (a) 1 gram of clarithromycin as active pharmaceutical ingredient; (b) 8 grams of an oil phase consisting of a 1:1 mixture of glyceryl tricaprylate and peppermint oil; (c) 40 grams of a surfactant mixture (Smix), the surfactant being Tween 80 and the co-surfactant being Transcutol P, present in a ratio optimized to maintain an isotropic and thermodynamically stable microemulsion; (d) 52 grams of an aqueous phase comprising purified water; EXAMPLE 2: Viscosity measurement

[0021] The viscosity of the clarithromycin microemulsion compositions was measured using a Brookfield viscometer. The device consists of a stationary cup and a rotating spindle. Based on the viscosity of the test sample, suitable spindles with different diameters and surface areas were selected. For each formulation, the spindle was immersed in the sample and rotated until a constant reading was obtained. The process was repeated three times to ensure reproducibility.

[0022] The results show that the viscosity of microemulsion compositions ME-1 to ME-9 gradually increased from 3.91 cps to 18.97 cps. All samples exhibited Newtonian flow behavior. The increase in viscosity correlated with an increasing oil phase and a decreasing surfactant concentration, which is typical for oil-in-water microemulsions. EXAMPLE 3: pH determination

[0023] The pH of each formulation was measured using a calibrated pH meter with a glass electrode. The electrode was immersed directly into the prepared microemulsion compositions, and the pH was recorded. Measurements were performed for all formulations (ME-1 to ME-9).

[0024] The results show that the pH of the formulations ranged between 7.06 (ME-1) and 4.56 (ME-9). The optimized formulation (ME-1) maintained a neutral pH of 7.06, suitable for oral administration. Formulations with a lower surfactant-to-oil ratio exhibited slightly acidic pH values. EXAMPLE 4: Electrical conductivity

[0025] Electrical conductivity was measured using a conductivity meter with a platinum electrode cell (cell constant frequency of 1 Hz). The microemulsion samples were placed between the platinum plates, and the conductivity values ​​were recorded in µS / cm.

[0026] The results show that the optimized composition ME-1 exhibited the highest conductivity at 0.215 µS / cm, indicating that it formed an oil-in-water (o / w) microemulsion. The conductivity values ​​decreased with increasing oil content, which is typical for water-in-oil systems. EXAMPLE 5: Particle size measurement

[0027] Particle size analysis was performed using a laser diffraction particle size analyzer. Samples were passed through a light beam in a sample chamber, and droplet sizes were recorded based on the scattered light patterns. Measurements were taken after multiple runs to ensure accuracy.

[0028] The results show that ME-1 had the smallest mean droplet size at 27.48 nm, indicating a well-dispersed microemulsion. Other formulations exhibited larger droplet sizes, up to 269.6 nm for ME-9. Smaller particle sizes increase the surface area of ​​the active ingredient and improve solubility and absorption. EXAMPLE 6: Zeta Potential

[0029] The zeta potential was measured to evaluate colloidal stability. The formulations were analyzed with a zeta potential analyzer to determine the surface charge across the electrical double layer at the interface.

[0030] The results show that the zeta potential ranged between -0.0015 V (ME-1) and -0.0030 V (ME-7), confirming sufficient electrostatic repulsion and colloidal stability. ME-1 demonstrated an optimal balance between stability and performance. EXAMPLE 7: Analysis of the active ingredient content

[0031] 1 ml of each microemulsion was mixed with 10 ml of acetonitrile, stirred for 30 minutes, and stored for 24 hours. The samples were centrifuged at 3000 rpm for 10 minutes. The supernatant was filtered, diluted with pH 1.2 buffer, and analyzed spectrophotometrically.

[0032] The results show that the drug content ranged from 98.54% (ME-1) to 90.09% (ME-9). The optimized formulation ME-1 exhibited the highest drug content, indicating effective drug loading and minimal degradation. EXAMPLE 8: Characterization of the microemulsion

[0033] Each formulation was visually examined in transparent containers under uniform lighting against a dark background to assess clarity.

[0034] The results show that ME-1 has excellent optical transparency and an elegant appearance, confirming the formation of a clear microemulsion. Investigation of mechanical resilience

[0035] The formulations were centrifuged at 1000 rpm for 10, 30, and 60 minutes and exposed to cyclic temperature conditions (4 °C, 25 °C, 45 °C) for six cycles (48 hours each).

[0036] The results show that no phase separation was observed in ME-1 under any loading conditions, demonstrating strong physical and chemical stability. Stomach stability

[0037] The formulations were exposed to simulated gastric fluid (pH 1.2) for 3 hours in a dialysis membrane-based dissolution system. The active ingredient content was measured at regular intervals.

[0038] The results show that ME-1 retained 85.23% of the drug content, while the pure clarithromycin microemulsion retained only 40.30%, confirming that peppermint oil significantly improves drug stability at acidic pH. EXAMPLE 9: In vitro dissolution study

[0039] The microemulsions were filled into dialysis membranes, sealed, and immersed in 900 ml of phosphate buffer (pH 1.2) at 37 ± 0.5 °C. Aliquots were taken over a period of 24 hours and analyzed spectrophotometrically.

[0040] The results show that the ME-1 composition of Higuchi kinetics (R 2 = 0.9904), with a non-Fickian release profile (n = 0.78) according to the Korsmeyer-Peppas model, indicating a sustained and controlled drug release. EXAMPLE 10: Antimicrobial Activity

[0041] The antibacterial activity of clarithromycin microemulsion was evaluated against Helicobacter pylori using the agar well diffusion method. The nutrient agar medium was prepared using 3.0 g of beef extract, 5.0 g of peptone, 8.0 g of sodium chloride (NaCl), and 15.0 g of agar in 1000 ml of distilled water. The mixture was sterilized in an autoclave at 200°C for 15 minutes. After autoclaving, the pH was adjusted to 7.2–7.4. The sterilized medium was poured into Petri dishes under aseptic conditions and allowed to solidify. The plates were then inoculated with H. pylori to create a uniform bacterial lawn. 7 mm diameter holes were punched into the agar using a sterile drill. Microemulsion samples were added to each well at concentrations of 20, 40, 60, 80 and 100 µg / ml.Distilled water served as a control, while a commercially available clarithromycin injection was used as a standard. The plates were incubated at 35–37°C for 72 hours. Zones of inhibition were measured in millimeters, and each test was performed three times to ensure reproducibility.

[0042] The results of the antimicrobial test showed a concentration-dependent increase in the H. pylori inhibition zones. At 20 µg / ml, the inhibition zone was 10 ± 1.3 mm and gradually increased to 28 ± 1.3 mm at 100 µg / ml for the optimized clarithromycin microemulsion. This demonstrated significantly higher antimicrobial activity compared to either plain clarithromycin or the control. The optimized microemulsion composition demonstrated superior efficacy due to the improved solubility, the synergistic effect of peppermint oil, and the improved stability of clarithromycin, confirming its potential in the treatment of H. pylori-related gastric infections. EXAMPLE 11: Accelerated Stability Study

[0043] An accelerated stability study was conducted to determine the physical and chemical stability of the optimized microemulsion (ME-1) under stress storage conditions. The formulation was stored for 6 months in controlled climate chambers at 25 ± 2°C / 60 ± 5% RH and for 3 months at 30 ± 2°C / 65 ± 5% RH and 40 ± 2°C / 75 ± 5% RH. At predefined intervals (1, 2, and 3 months), the samples were analyzed for key stability parameters such as drug content (%), viscosity (cps), and pH.

[0044] The stability results for ME-1 showed minimal changes in all tested parameters during the storage period. The drug content remained high and constant, reaching 98.52%, 98.31%, and 97.78% after 1, 2, and 3 months, respectively. Viscosity showed only a slight decrease from 3.91 cps to 3.54 cps over the same period, while pH values ​​remained relatively stable between 7.06 and 7.00. These results demonstrate excellent physicochemical stability of the ME-1 microemulsion under accelerated conditions and confirm its suitability for long-term storage and commercial pharmaceutical applications. Examples

[0045] 1. A pharmaceutical microemulsion composition of clarithromycin with improved stability, bioavailability and antimicrobial activity against Helicobacter pylori, comprising: (a) 1 gram of clarithromycin as active pharmaceutical ingredient; (b) 8 grams of an oil phase consisting of a 1:1 mixture of glyceryl tricaprylate and peppermint oil; (c) 40 grams of a surfactant mixture (Smix), the surfactant being Tween 80 and the co-surfactant being Transcutol P, present in a ratio optimized to maintain an isotropic and thermodynamically stable microemulsion; (d) 52 grams of an aqueous phase comprising purified water; wherein the microemulsion composition is characterized by a mean droplet size of less than 30 nanometers, a viscosity in the range of 3.91 to 18.97 centipoise (cps), and a pH in the range of 4.56 to 7.06; and wherein the composition provides improved solubility, bioavailability and physicochemical stability of clarithromycin under gastric pH conditions, thereby improving therapeutic efficacy against Helicobacter pylori.

Claims

[1] Pharmaceutical microemulsion composition of clarithromycin with improved stability, bioavailability and antimicrobial activity against Helicobacter pylori, comprising: (a) 1 gram of clarithromycin as active pharmaceutical ingredient; (b) 8 grams of an oil phase consisting of a 1:1 mixture of glyceryl tricaprylate and peppermint oil; (c) 40 grams of a surfactant mixture (Smix), the surfactant being Tween 80 and the co-surfactant being Transcutol P, present in a ratio optimized to maintain an isotropic and thermodynamically stable microemulsion; (d) 52 grams of an aqueous phase comprising purified water; wherein the microemulsion composition is characterized by a mean droplet size of less than 30 nanometers, a viscosity in the range of 3.91 to 18.97 centipoise (cps), and a pH in the range of 4.56 to 7.06; and wherein the composition provides improved solubility, bioavailability, and physicochemical stability of clarithromycin under gastric pH conditions, thereby improving therapeutic efficacy against Helicobacter pylori. [2] The pharmaceutical microemulsion composition according to claim 1, wherein the surfactant Tween 80 and the co-surfactant Transcutol P are present in a ratio of 3:1 to improve water absorption and stability. [3] The pharmaceutical microemulsion composition according to claim 1, wherein the oil phase comprises glyceryl tricaprylate and peppermint oil, wherein peppermint oil acts as a pH modulator to improve the stability of clarithromycin under gastric conditions. [4] The pharmaceutical microemulsion composition according to claim 1, wherein the particle size of the microemulsion is in the range of 10 to 50 nm, thereby optimizing the solubility and bioavailability of the drug. [5] The pharmaceutical microemulsion composition according to claim 1, wherein the zeta potential is in the range of -0.0015 V to -0.0030 V, thereby ensuring colloidal stability and preventing particle aggregation.