Effective microemulsion formulation in the treatment of hypertension

Abstract

The invention relates to a medicine formed by a microemulsion derived from lipid-based nano drug delivery systems containing nadolol as the active ingredient for use in the treatment of hypertension, and to the production method of said product. With said nano formulation, a medicine having high bioavailability and treatment compliance values, as well as improved accessibility, is obtained.

Description

[0001] DESCRIPTION

[0002] EFFECTIVE MICROEMULSION FORMULATION IN THE TREATMENT OF HYPERTENSION

[0003] Technical Field of the Invention

[0004] The invention relates to a nano formulation produced by loading the active ingredient nadolol into a microemulsion system derived from lipid-based nano drug delivery systems, and to the production method thereof. Said formulation is used in the treatment of hypertension.

[0005] State of the Art

[0006] Hypertension, also known as high blood pressure, is a medical condition characterised by a high level of force exerted by the blood against the walls of the arteries. Measured in millimetres of mercury (mmHg), blood pressure is expressed by two values: systolic pressure (the force during heartbeats) and diastolic pressure (the force between heartbeats). While normal blood pressure is typically around 120 / 80 mmHg, hypertension occurs when these values consistently exceed the normal range. Longterm high blood pressure can strain the arteries, heart and other organs, increasing the risk of cardiovascular diseases such as heart attack, stroke and heart failure. Lifestyle factors, genetics and other health conditions may contribute to the development of hypertension. Preventive treatments and routine blood pressure tests are of great importance in maintaining cardiovascular health and reducing the symptoms of hypertension.

[0007] Treatment of hypertension typically involves a multifaceted approach aimed at lowering blood pressure and reducing the risk of associated complications. Lifestyle changes constitute a fundamental component of hypertension management. These may include adopting a healthy diet, engaging in regular physical activity, maintaining a healthy weight and reducing alcohol consumption. Medicines may also be prescribed to effectively control blood pressure. These medicines generally target various mechanisms in the body, such as diuretics to reduce fluid retention, beta blockers to lower heart rate, angiotensin-converting enzyme (ACE) inhibitors to relax blood vessels, and calcium channel blockers to dilate arteries. Nadolol, which is frequently used in the treatment of hypertension, is classified as a beta blocker, a type of medicine that affects the heart and circulation. Nadolol works by blocking the effect of certain natural substances in the body, such as adrenaline, which can increase heart rate and blood pressure. As a non-selective beta blocker, nadolol acts on both beta-1 receptors in the heart and beta-2 receptors in the blood vessels. Thus, it helps reduce the workload on the heart and dilate the blood vessels, thereby lowering blood pressure. Various drug delivery systems have been developed to deliver medicines such as nadolol into the patient’s body.

[0008] Drug delivery systems encompass a range of techniques and formulations designed to ensure the effective administration of therapeutic agents within the body. Many examples can be given for drug delivery systems. Oral drug delivery through tablets or capsules is a common method for systemic drug absorption. Injectable routes such as intravenous or intramuscular injections allow for rapid and precise drug delivery, which is vital in critical situations. Transdermal systems use patches or topical formulations to release medicines slowly through the skin. Inhalation methods facilitated by inhalers or nebulisers target the respiratory system and are particularly useful in treating respiratory conditions. Implantable devices, including drug-releasing implants or microchips, provide controlled and continuous drug release over an extended period. Nano-scale drug delivery increases targeted stability and distribution by using small carriers for drug encapsulation. The selection of a specific delivery system depends on factors such as the properties of the drug, the target tissue and the desired release kinetics.

[0009] Nadolol is an active ingredient with low solubility (between 20% and 40%). The low solubility of nadolol leads to the need for higher doses in order to achieve an optimum therapeutic effect. In patient groups such as the elderly and children, who frequently experience difficulty swallowing, administration in solid dosage form causes additional problems. The high side-effect profile associated with high doses not only reduces patient compliance during the clinical stage but also increases costs at the production stage.

[0010] Due to the limitations and inadequacies of the state of the art, the low solubility of nadolol in medicines in tablet form, the resulting necessity to continue treatment with higher doses to achieve an optimum therapeutic effect, and the difficulty experienced by patients with swallowing problems in using the medicine, it has become necessary to develop an effective nano formulation for the treatment of hypertension.

[0011] Brief Description and Aims of the Invention

[0012] The invention relates to a lipid-based nano drug delivery system containing the active ingredient nadolol, which is to be used for the treatment of hypertension. In the invention, nadolol is loaded into a nano drug delivery system in the form of a microemulsion. The microemulsion that is the subject of the invention comprises cinnamon oil in the oil phase, distilled water in the aqueous phase, Tween 20 as a surfactant, and propylene glycokethanol as a co-surfactant. The developed drug delivery system is intended for oral use.

[0013] Since microemulsions have a high surface area, they possess a high solubilisation capacity for active substances. The surfactants and co-surfactants used temporarily open the tight junctions between intestinal cells, thereby contributing to improved bioavailability. As the surfactants and co-surfactants are non-ionic, their irritating effect on the mucosa is minimised. In addition, the addition of co-surfactants to formulations enables a reduction in the amount of surfactant used. Having low viscosity facilitates operations such as filling, transferring and transporting in the pharmaceutical industry. In addition, microemulsions increase the solubility of the active ingredient, thereby enhancing its bioavailability.

[0014] An aim of the invention is to obtain a medicine with a high bioavailability value. For this purpose, a microemulsion system was chosen as the drug delivery system, which ensures faster absorption and higher bioavailability compared to solid dosage forms and emulsions of active ingredients.

[0015] Another aim of the invention is to increase compliance with medicines containing nadolol. Using microemulsions that are easier to swallow instead of solid dosage forms in patient groups such as the elderly and children, who often experience difficulty swallowing, improves patient compliance with treatment. In addition, by improving the bioavailability of nadolol, treatment can be achieved with lower doses, thereby minimising the side effects of oral administration.

[0016] Furthermore, the invention aims to obtain a more affordable medicine. Microemulsions demonstrate good thermodynamic stability. Owing to their thermodynamic stability, their production and sterilisation are relatively simpler and cheaper. They also allow easy scale-up during production. For these reasons, the use of microemulsions as the delivery system for nadolol increases the accessibility of the obtained medicine.

[0017] Description of Drawings

[0018] Figure 1. Pseudo-ternary phase diagram of the microemulsion formulation.

[0019] Figure 2. %release graph in the in vitro gastric medium.

[0020] Figure 3. %release graph in the in vitro intestinal medium.

[0021] Figure 4. %viability graph.

[0022] Figure 5. Graphs of the estimated human %Favalue, estimated human Petr, and rat Peff values determined from the in-situ perfusion study.

[0023] Detailed Description of the Invention

[0024] The invention relates to a lipid-based nano drug delivery system containing the active ingredient nadolol, which is to be used for the treatment of hypertension. In the invention, nadolol is loaded into a microemulsion system as a nano drug carrier.

[0025] Microemulsions are isotropically transparent, thermodynamically stable and spontaneously forming dispersion systems obtained by stabilising two immiscible phases, such as water and oil, through the use of a surfactant and usually a cosurfactant. Microemulsions comprise cinnamon oil as the oil phase, distilled water as the aqueous phase, Tween 20 as the surfactant, and propylene glycokethanol as the co-surfactant.

[0026] The lipid-based nano formulation for use in the treatment of hypertension comprises: a. a drug delivery system in the form of a microemulsion containing, by weight, 10-18% cinnamon oil as the oil phase, 4-40% distilled water as the aqueous phase, 1-30% surfactant, and 20-65% co-surfactant; and b. as the active ingredient, nadolol and / or its salts, which is an antihypertensive agent constituting 0.02-10% (w / w) of the total weight of the drug delivery system. Microemulsions may form spontaneously or with minimal energy due to the suitable ratio of the phases used in their structure.

[0027] An ideal implementation of the formulation comprises: a. a drug delivery system in the form of a microemulsion containing, by weight, 17.22% cinnamon oil as the oil phase, 5.4% distilled water as the aqueous phase, 15.47% Tween 20 as the surfactant, and 61.91 % Capryol 90 as the co-surfactant; and b. as the active ingredient, nadolol and / or its salts, which is an antihypertensive agent constituting 0.02-10% (w / w) of the total weight of the drug delivery system.

[0028] Another ideal implementation of the formulation comprises: a. a drug delivery system in the form of a microemulsion containing, by weight, 10.65% cinnamon oil as the oil phase, 33.25% distilled water as the aqueous phase, 28.05% Tween 20 as the surfactant, and 28.05% polyethylene glycol (PEG):ethanol (3:1 ) as the co-surfactant; and b. as the active ingredient, nadolol and / or its salts, which is an antihypertensive agent constituting 0.02-10% (w / w) of the total weight of the drug delivery system.

[0029] Pseudo-ternary phase diagrams were constructed to determine the ideal component ratio of the formulation. While constructing the phase diagram, the mixture of oil, surfactant and co-surfactant was titrated with distilled water until the turbidity point, and the amount of water absorbed was recorded. The obtained results were recorded and triangular phase diagrams were plotted. Optimum emulsion formulations were calculated and developed using the centroid of the region providing the largest emulsion area.

[0030] The ideal composition obtained is shown in the pseudo-ternary phase diagram in Figure 1 . The given visual represents the pseudo-ternary phase system drawn with the aid of software for the optimum component ratios obtained from the microemulsion trials. The components located at the sides of the triangle correspond to the oil, surfactant-co-surfactant, and aqueous phases. The numbers on the sides of the triangle indicate the phase ratios. The dark area in the visual represents the proportion of water absorbed by the formulation. The white circle in the area indicates the optimum component ratio.

[0031] Microemulsions have the ability to simultaneously carry both oil-soluble and water- soluble active substances due to the presence of both oil and aqueous phases in their content. The formulations protect the active ingredient against enzymatic hydrolysis, oxidation and first-pass effects. In addition, they ensure less influence from varying physiological conditions such as food intake, bile secretion and pH.

[0032] The production method of a lipid-based nano formulation for use in the treatment of hypertension that is the subject of the invention comprises the process step of: i. mixing 10-15% by weight of the oil phase and 56.1 % by weight of the surfactant + co-surfactant with a magnetic stirrer, and then adding 30- 35% by weight of the aqueous phase.

[0033] An implementation of the production method of a lipid-based nano formulation for use in the treatment of hypertension that is the subject of the invention comprises the process step of i. mixing 10.65% by weight of the oil phase and 50-55% by weight of the surfactant + co-surfactant with a magnetic stirrer, and then adding 33.25% by weight of the aqueous phase.

[0034] The microemulsion formulation exhibited a droplet size below 200 nm and a homogeneous distribution, consistent with the literature. For the evaluation of the thermodynamic stability of the emulsion formulations, they were subjected three times to heating (4±2°C)-cooling (40±2°C) and freezing (-20±2°C)-thawing (40±2°C) cycles, followed by centrifugation. No physical change was observed in the microemulsion formulation selected as ideal.

[0035] In the in vitro release study of the formulation, the microemulsion formulation showed a release above 95% within 4 hours at pH 1 .2. The graph shown in Figure 2 presents the release profile at pH 1.2 (gastric medium) of the selected microemulsion formulation coded as M2-NDL. The horizontal axis represents time, while the vertical axis represents the percentage of active ingredient released into the medium over time. At pH 6.8, corresponding to the intestinal emptying time of 8 hours, a release above 96% was observed. The graph shown in Figure 3 presents the release profile at pH 6.8 (intestinal medium) of the selected microemulsion formulation coded as M2-NDL. The horizontal axis represents time, while the vertical axis represents the percentage of active ingredient released into the medium over time.

[0036] In cytotoxicity studies, the formulations demonstrated cell viability above 95%. When the studies in the literature were evaluated, the formulation was accepted as non-toxic. In the graph shown in Figure 4, the effect of the selected microemulsion formulation coded as M2-NDL on the cell viability of the human colon epidermal adenocarcinoma (Caco-2) cell line was measured at the times given on the horizontal axis, and the obtained values were given as percentages on the vertical axis.

[0037] Cell permeability studies were conducted using the Caco-2 cell line. In the study, measurements were made in both directions, from apical to basolateral (A^B) and from basolateral to apical (B^A). The A^B direction was designed to simulate the transfer of the studied molecule from the intestinal lumen to the systemic circulation, while the B^A direction was designed to simulate the transfer from the blood to the intestinal lumen. It was observed that the transfer in the A^B direction was higher.

[0038] The effects of different delivery systems on the intestinal transport of NDL were evaluated using the in-situ single-pass intestinal perfusion (SPIP) method. The study was carried out at Anadolu University using Sprague-Dawley rats obtained from the Experimental Animals Research and Application Unit of Anadolu University (Eski§ehir) (File registration no. 21 -43, Decision no. 2021 -43). The SPIP method is recommended by the FDA as an in vivo approach for predicting oral bioavailability in humans.

[0039] In the SPIP study, surgical procedures were performed under anaesthesia. Anaesthesia was achieved by intraperitoneal administration of a combination of ketamine (90 mg / kg) and xylazine (10 mg / kg). Under anaesthesia, the abdominal wall was incised to expose the intestines, and the ileum was identified. The length of the segment to be perfused was adjusted to 8.0-10.0 cm for the ileum. The flow rate was adjusted to 0.2 ml / min using a peristaltic pump. Samples were collected every 10 minutes for 60 minutes and analysed by HPLC.

[0040] In the in situ intestinal perfusion study, golytely solution was used as the perfusion medium. The golytely solution used was prepared with 25 mmol / L NaCI, 10 mmol / L KCI, 40 mmol / L Na2SO4, 20 mmol / L NaHCO3and 80 mmol / L mannitol, and its pH was adjusted to 7.4. To investigate intestinal absorption, nadolol was used as the model drug, metoprolol tartrate (MTT), a high-permeability compound belonging to biopharmaceutical classification system (BCS) class I, was used for comparison of intestinal permeability, and phenol red (PR) was used for water balance determination. The concentration of the studied active ingredient NDL was selected as 40 mg / ml. After the perfused intestinal segments reached equilibrium, the studies were carried out as described below.

[0041] GROUP 1 : The ileum, to which NDL was added in the perfusion solution, was perfused for 60 minutes. Samples were collected every 10 minutes, and the amounts of MTT, PR and NDL in the samples were determined using the developed HPLC method.

[0042] GROUP 2: The ileum, to which the NDL-loaded formulation (NDL-loaded M2) was added in the perfusion solution, was perfused for 60 minutes. Samples were collected every 10 minutes, and the amounts of PR and NDL in the samples were determined using the developed HPLC method.

[0043] GROUP 3: The ileum, to which NDL and the blank formulation (Blank M2) were added in the perfusion solution, was perfused for 60 minutes. Samples were collected every 10 minutes, and the amounts of PR and NDL in the samples were determined using the developed HPLC method.

[0044] The graphs of the data obtained from the study are given in Figure 5. Figure 5 / A shows the graph of the estimated percentage of absorbed active ingredient fraction (Fa) in humans, determined using the effective permeability (Peff) values obtained from rats. Figure 5 / B shows the graph of the estimated human Peff value obtained from the experiments. Figure 5 / C shows the graph of the Peff value determined from rats as a result of the experiments.

[0045] In the first group, conducted to evaluate the permeability of MTT and NDL, it was observed that the permeability of NDL in the golytely solution was considerably lower compared to MTT. In the experiments conducted with the second and third groups, the transfer of the active ingredient in the loaded and blank formulations was evaluated. It was determined that the microemulsion formulation increased the transfer of the active ingredient. It was considered that penetration-enhancing excipients, such as surfaceactive agents in the formulation, may improve paracellular transport from the intestines by inducing structural arrangements in the tight junctions located on the apical surface of enterocytes.

Claims

CLAIMS1. A lipid-based nano formulation for use in the treatment of hypertension, comprising a. a drug delivery system in the form of a microemulsion containing, by weight, 10-18% cinnamon oil as the oil phase, 4-40% distilled water as the aqueous phase, 1-30% surfactant, and 20-65% co-surfactant, and b. nadolol and / or its salts, which is an antihypertensive agent constituting 0.02- 10% (w / w) of the total weight of the drug delivery system, as the active ingredient.

2. The lipid-based nano formulation for use in the treatment of hypertension according to claim 1 , comprising a. a drug delivery system in the form of a microemulsion containing, by weight, 17.22% cinnamon oil as the oil phase, 5.4% distilled water as the aqueous phase, 15.47% Tween 20 as the surfactant, and 61.91 % Capryol 90 as the co-surfactant; and b. nadolol and / or its salts, which is an antihypertensive agent constituting 0.02- 10% (w / w) of the total weight of the drug delivery system, as the active ingredient.

3. The lipid-based nano formulation for use in the treatment of hypertension according to claim 1 , comprising a. a drug delivery system in the form of a microemulsion containing, by weight, 10.65% cinnamon oil as the oil phase, 33.25% distilled water as the aqueous phase, 28.05% Tween 20 as the surfactant, and 28.05% polyethylene glycol (PEG):ethanol (3:1 ) as the co-surfactant; and b. nadolol and / or its salts, which is an antihypertensive agent constituting 0.02- 10% (w / w) of the total weight of the drug delivery system, as the active ingredient.

4. The lipid-based nano formulation for use in the treatment of hypertension according to claim 1 , comprising a surfactant selected from polysorbate or a derivative thereof, PEG sorbitan monolaurate or a derivative thereof, or polyoxyethylene sorbitan monolaurate or a derivative thereof.

5. The lipid-based nano formulation for use in the treatment of hypertension according to claim 1 , comprising a co-surfactant selected from Capryol 90 or a derivative thereof, propylene glycol, glycerine, or ethanol.

6. A medicine comprising a formulation according to any one of claims 1 to 5.

7. The medicine according to claim 6, comprising a formulation in the form of a gel, capsule, or syrup.

8. Production method of a lipid-based nano formulation for use in the treatment of hypertension according to any one of claims 1 to 5, comprising the process steps of: a. dissolving 4% (w / w) nadolol in cinnamon oil by stirring at 50-1000 rpm for 5 minutes to 2 hours at room temperature to obtain the oil phase, and b. adding Tween 20 to the prepared oil phase and dissolving it by stirring at 50-1000 rpm for 5 minutes to 2 hours at room temperature.

9. The production method of a lipid-based nano formulation for use in the treatment of hypertension according to claim 8, wherein, in the case where Capryol 90 is used as the co-surfactant, the cinnamon oil mentioned in step (a) is 17.22% by weight, and the Tween 20 mentioned in step (b) is 15.47% by weight.

10. The production method of a lipid-based nano formulation for use in the treatment of hypertension according to claim 8, wherein, in the case where polypropylene glycokethanol (3: 1 ) is used as the co-surfactant, the cinnamon oil mentioned in step (a) is 10.65% by weight, and the Tween 20 mentioned in step (b) is 28.05% by weight.

11. The production method of a lipid-based nano formulation for use in the treatment of hypertension according to claim 8, wherein, in the case where Capryol 90 is used as the co-surfactant, following step (b), the method comprises the process steps of:c. adding 62.90% by weight of Capryol 90 sequentially to the oil phase and dissolving it by stirring at 50-1000 rpm for 5 minutes to 2 hours at room temperature, and d. adding 5.4% by weight of distilled water dropwise to the obtained mixture by titration, stirring at 50-1000 rpm for 5 minutes to 2 hours, and obtaining a homogeneous mixture.

12. The production method of a lipid-based nano formulation for use in the treatment of hypertension according to claim 8, wherein, in the case where a polypropylene glycokethanol (3:1 ) mixture is used as the co-surfactant, following step (b), the method comprises the process steps of: c. adding 28.05% by weight of Capryol 90 sequentially to the oil phase and dissolving it by stirring at 50-1000 rpm for 5 minutes to 2 hours at room temperature, and d. adding 33.25% by weight of distilled water dropwise to the obtained mixture by titration, stirring at 50-1000 rpm for 5 minutes to 2 hours, and obtaining a homogeneous mixture.

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