A lipid lyotropic liquid crystal drug carrier composition, its preparation method and use in oral delivery

Abstract

This invention proposes a lipid-lyotropic liquid crystal drug-loaded composition, its preparation method, and its application in oral delivery, belonging to the fields of drug delivery systems and functional foods. The composition comprises an oil phase containing monooleic glycerol and linoleic acid, and an aqueous phase containing Pluronic F127, KCl, and nicotinamide. This invention utilizes a high-shear flow field within an extrusion 3D printing nozzle to induce the transformation of liquid crystal domains from a random multi-domain structure to an oriented ordered structure, achieving active programming of the curvature and connectivity of nanochannels. This carrier utilizes the natural pH gradient of the gastrointestinal tract as an endogenous trigger signal, maintaining structural stability in the acidic environment of the stomach to achieve sustained release, undergoing a phase transition in the neutral environment of the intestine to promote drug release, and simultaneously enhancing cellular absorption through redispersion to form nanocolloids. This invention overcomes the limitations of traditional passive self-assembly modes of liquid crystals, providing a green and efficient new strategy for the precise oral delivery of water-soluble nutrients.

Description

Technical Field

[0001] This invention belongs to the field of drug delivery systems and functional food technology, and particularly relates to a lipid-lyotropic liquid crystal drug-loaded composition, its preparation method, and its application in oral delivery. Background Technology

[0002] With the rise of functional foods and precision nutrition, higher demands are being placed on the delivery efficiency, controllability of release rhythm, and personalized adaptation of active ingredients. Nicotinamide (the amide form of vitamin B3), as an important water-soluble nutrient, plays a crucial role in cellular energy metabolism, DNA repair, antioxidant defense, and skin barrier regulation, and is widely used in functional foods and dietary supplements. However, due to its high water solubility and small molecular weight, nicotinamide is readily dissolved and absorbed rapidly in the stomach and upper small intestine after oral administration, leading to large fluctuations in blood drug concentration and significant individual differences in bioavailability, making sustained release or intestinal targeting difficult. Furthermore, under extreme processing or storage conditions such as high temperature and high humidity, nicotinamide may partially hydrolyze into nicotinic acid. While the latter has similar physiological functions, it can easily cause adverse reactions such as skin flushing at higher doses, affecting product safety. These factors collectively restrict the efficient, stable, and personalized application of nicotinamide in functional foods.

[0003] Given the difficulty in controlling the release of water-soluble nutrients such as nicotinamide using traditional carriers, intelligent delivery systems that respond to physiological stimuli such as pH, enzyme activity, or ionic strength have become a research focus. However, existing stimulus-responsive delivery systems mostly rely on non-food-grade synthetic polymers, which are insufficient to meet the safety and industrialization requirements of oral products. In contrast, the naturally occurring pH gradient in the gastrointestinal tract (gastric pH ≈ 1.5-3.0, small intestinal pH ≈ 6.0-7.4) provides an endogenous triggering signal that does not require exogenous stimulation, which can be used to drive carrier structural changes and achieve site-specific release of active ingredients.

[0004] Lipid-Lyotropic Liquid Crystals (LLCs) are a class of soft matter systems that combine the long-range order of crystals with the fluidity of liquids. Recent research indicates that the internal configuration and external morphology of drug delivery systems are key variables determining delivery efficiency. Unlike traditional emulsions and polymers, lipid LLCs possess a stable mesoscopic structure formed by the interweaving of nanochannels and lipid bilayers, exhibiting membrane-mimetic characteristics and a high internal interfacial area. Theoretically, this can provide a suitable loading microenvironment for different types of drugs. Furthermore, lipid LLCs exhibit high responsiveness to pH, hydration levels, and the digestive environment. Phase transitions can regulate channel curvature, pore size, and interfacial characteristics, thereby achieving drug protection, release, and absorption promotion in the gastrointestinal tract. Non-electrode lipids (such as glyceryl monooleate) can self-assemble in water to form inverted lyotropic liquid crystals; all components are food-grade, possessing both good biocompatibility and structural tunability. Among them, the reversed bicontinuous cubic phase (with three-dimensional water channels) and the reversed hexagonal phase (with one-dimensional water channels) can simultaneously encapsulate hydrophilic and hydrophobic active molecules, making them ideal co-delivery carriers. Therefore, lipid LLCs are expected to become ideal carriers for improving the oral stability, bioavailability, and long-term application potential of nicotinamide.

[0005] However, the construction and regulation of existing lipid LLC systems still mainly rely on the thermodynamic self-assembly mode where components determine structure, lacking effective means for active and precise regulation of their mesoscopic structure (see Rakotoarisoa M, Angelov B, Espinoza S, et al. Composition-switchable liquid crystalline nanostructures as green formulations of curcumin and fish oil [J]. ACSSustainable Chemistry&Engineering, 2021, 9(44): 14821-35). The release and digestion behavior of lipid LLCs in the gastrointestinal tract are essentially influenced by their initial mesoscopic topology, but existing research lacks a systematic explanation of this.

[0006] 3D printing technology exhibits unique advantages in constructing structure-function integrated materials. It can not only customize macroscopic geometries but also influence and even guide the formation of nanoscale ordered structures in liquid crystal polymers (LLCs) during extrusion through shear flow fields. Existing research has shown that the high-shear flow fields formed within the nozzle during extrusion 3D printing have the potential to induce microscopic orientation and hierarchical structure reconstruction in soft matter (e.g., Gantenbein et al., Nature, 2018; Houliet's doctoral dissertation, 2024). However, these studies all focus on thermotropic liquid crystal polymer (LCP) systems, aiming to control the mechanical properties of structural materials (such as axial stiffness), and do not address lipid lyotropic liquid crystal (LLC) systems, let alone the oral delivery of water-soluble active ingredients. The working mechanisms of thermotropic LCPs and lyotropic LLCs are fundamentally different; the former is a temperature-driven anhydrous system, while the latter is a multi-factor coupled system dependent on the hydration environment. This makes it impossible to directly apply the above technologies to the construction of lipid LLC oral delivery systems. Currently, there is a lack of research on the deep integration of 3D printing and lyotropic liquid crystal self-assembly behavior. In particular, in the scenario of water-soluble nutrient delivery, how to regulate the microstructure of liquid crystal through printing process and thus optimize its encapsulation efficiency and controlled release performance remains a blank.

[0007] In summary, existing lipid LLC systems rely on a passive self-assembly mode where components determine structure, making it impossible to achieve active regulation of mesoscopic structure without altering the formulation. Furthermore, the mechanisms by which release and digestion behaviors are influenced by mesoscopic topology lack systematic elucidation. Existing stimulus-responsive delivery systems largely depend on non-food-grade synthetic polymers, which struggle to meet the safety and industrialization requirements of oral products. Simultaneously, research on the deep integration of 3D printing and lyotropic liquid crystal self-assembly behavior is still lacking, and the regulatory mechanisms of printing processes on liquid crystal microstructures remain unclear. These issues collectively restrict the efficient, stable, and personalized application of nutrients in functional foods and limit the development of lipid LLC carriers in oral drug delivery. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention proposes a lipid-lyotropic liquid crystal drug delivery composition, its preparation method, and its application in oral delivery to achieve effective delivery of nicotinamide. This system aims to solve the stability problems of nicotinamide, such as large fluctuations in blood drug concentration and low bioavailability due to rapid absorption after oral administration, and its tendency to hydrolyze into nicotinic acid under high temperature and humidity conditions. It achieves protective sustained-release of nicotinamide in the stomach and targeted release in the intestine, improving its gastrointestinal stability and absorption efficiency.

[0009] Meanwhile, in order to overcome the passive self-assembly mode of existing lipid LLC systems that rely on "components determining structure", this invention utilizes the shear flow field in the 3D printing process to induce the orientation and reconstruction of the liquid crystal mesostructure, thereby achieving active programming of the liquid crystal phase, lattice parameters and nanopore arrangement, and thus completing the precise control of the mesostructure without changing the formulation.

[0010] Furthermore, to address the issues that existing stimulus-responsive delivery systems often rely on non-food-grade synthetic polymer materials and lack deep integration between 3D printing and lyotropic liquid crystal self-assembly, this invention utilizes food-grade raw materials such as monoolein (MO) to prepare a green and safe intelligent delivery system using 3D printing technology under room temperature and organic solvent-free conditions. This system aims to meet the stringent safety and industrialization requirements of the functional food and precision nutrition fields.

[0011] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing a lipid-lyotropic liquid crystal drug-loaded composition, comprising the following steps: The oil phase was prepared by mixing monooleic glycerides with fatty acids; An aqueous phase is prepared by dissolving surfactants, electrolytes, and active ingredients in water, and the pH is adjusted to acidity. The aqueous phase and the oil phase are mixed and homogenized to form a lyotropic liquid crystal phase. The lyotropic liquid crystal phase is extruded, and the shear flow field generated during the extrusion process induces the orientation reconstruction of the mesoscopic structure of the lyotropic liquid crystal phase. After extrusion, the phase is allowed to stand to obtain the lipid lyotropic liquid crystal drug-loaded composition. The extrusion process is 3D printing extrusion, and the nozzle diameter of the 3D printing extrusion is 0.16-0.34 mm; for example, the nozzle diameter of the 3D printing extrusion is 0.16 mm or 0.34 mm.

[0012] This invention employs 3D printing extrusion technology, using high-shear flow fields generated by nozzles of varying diameters to induce orientation reconstruction of the liquid crystal mesoscopic structure. After printing, the formulation is allowed to stand at room temperature, allowing the liquid crystal structure to fully balance and stabilize. The shear flow field control mechanism of this method lies in the fact that the high-shear flow field within the nozzle causes the liquid crystal domains to rotate and align, transforming a random multi-domain structure into a directional oriented structure. Simultaneously, the shearing action alters the curvature, connectivity, and arrangement of the nanochannels, thereby regulating the drug diffusion path and release kinetics. By adjusting the nozzle diameter and printing parameters, this invention enables active programming of the liquid crystal phase, lattice parameters, and nanochannel arrangement, breaking through the traditional passive self-assembly mode of "components determining structure."

[0013] Furthermore, the fatty acid is linoleic acid, and the mass ratio of monooleic glyceride to fatty acid in the oil phase is 97:3.

[0014] Furthermore, the surfactant is Pluronic F127, the electrolyte is KCl, the mass percentage concentration of Pluronic F127 in the aqueous phase is 1%, the concentration of KCl is 150 mM, and the pH value of the aqueous phase is 2.0.

[0015] Furthermore, the active ingredient is a water-soluble active substance, and the mass percentage concentration of the active ingredient in the aqueous phase is 0.2%; for example, the water-soluble active substance is nicotinamide.

[0016] Furthermore, the mass ratio of the oil phase to the water phase is 7:3.

[0017] Furthermore, the lyotropic liquid crystal phase has a nanoscale water channel structure, and the active ingredient is distributed in the water channel structure; the shear flow field generated during the extrusion processing of the lipid lyotropic liquid crystal drug-loaded composition causes the mesoscopic structure of the lyotropic liquid crystal phase to undergo orientation reconstruction; the orientation reconstruction of the mesoscopic structure is manifested as the liquid crystal domains changing from a random multi-domain structure to an oriented structure, and the curvature, connectivity, and arrangement of the water channels are changed.

[0018] Furthermore, the lyotropic liquid crystal phase exhibits a hexagonal phase structure under pH conditions of 1.5-3.0, and the nanoscale water channels are one-dimensional water channels; under pH conditions of 6.0-7.4, the hexagonal phase structure undergoes a phase transition, and the connectivity of the water channels increases.

[0019] Furthermore, the settling time is 24 hours.

[0020] The present invention also provides a lipid-lyotropic liquid crystal drug-loaded composition prepared according to the above preparation method.

[0021] The present invention also provides the application of the above-mentioned lipid lyotropic liquid crystal drug delivery composition in the preparation of an oral delivery system.

[0022] Furthermore, the oral delivery system utilizes the gastrointestinal pH gradient as an endogenous trigger signal. In the acidic environment of the stomach, the lipid-lyotropic liquid crystal drug-loaded composition maintains a hexagonal phase structure to achieve sustained release of the active ingredient. In the neutral or weakly alkaline environment of the intestine, the lipid-lyotropic liquid crystal drug-loaded composition undergoes a phase transition to achieve targeted release of the active ingredient. The lipid-lyotropic liquid crystal drug-loaded composition forms nano- or submicron-sized colloidal particles in the intestinal environment.

[0023] Specifically, this invention utilizes the natural pH gradient of the gastrointestinal tract as an endogenous trigger signal to achieve site-specific release of nicotinamide. In the acidic environment of the stomach (pH=1.5-3.0), the lipid liquid crystal maintains its complete hexagonal phase structure, with closed or tortuous nanochannels, resulting in slow nicotinamide release and protecting the drug from gastric acid degradation. Upon entering the neutral or weakly alkaline environment of the intestinal tract (pH=6.0-7.4), the lipid undergoes a phase transition, increasing water channel connectivity and pore size, leading to rapid nicotinamide release and improved absorption efficiency. The scientific principle behind this pH-responsive phase transition lies in the change in the protonation state of monooleoglycerate molecules under different pH conditions, resulting in a change in the effective cross-sectional area of ​​the lipid head group. This, in turn, drives the liquid crystal to transition from a hexagonal phase to a cubic or layered phase, achieving precise control of channel curvature and connectivity, ultimately achieving gastric protection and targeted intestinal release of the drug.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects: First, this invention constructs a novel pH-responsive oral delivery system based on a lipid LLC system. This system comprises nanochannels and a lipid bilayer network, forming a stable mesoscopic structure. This structure can respond to changes in pH, hydration levels, and the digestive environment in the gastrointestinal tract, and regulate channel properties through phase transitions, thereby achieving effective protection, programmed release, and promoted absorption of nutrients.

[0025] The core breakthrough of this invention lies in the active programming of the lipid liquid crystal mesoscopic structure. Unlike traditional systems that rely on passive thermodynamic self-assembly where "components determine structure," this invention innovatively introduces 3D printing technology, utilizing shear flow fields to induce liquid crystal domains to transform from a random multi-domain structure into a highly oriented ordered structure. This method, without altering the core formulation, achieves precise on-demand control of lattice orientation, topology, and phase evolution, establishing a multi-dimensional control model of "printing parameters-liquid crystal structure-release performance." This provides a novel methodological support for the rational design of functional nutrient delivery systems, driving the field's shift from empirical trial-and-error to structure-driven approaches.

[0026] At the application level, the lipid-lyotropic liquid crystal drug delivery composition of this invention also exhibits excellent performance. Specifically, the carrier demonstrates redispersibility and colloidal behavior in the intestinal environment, creating favorable conditions for the release and absorption of nutrients. On the one hand, shear programming alters the microenvironment and diffusion pathway of nutrients within the carrier, precisely controlling release kinetics by regulating the connectivity and arrangement of nanochannels, effectively avoiding burst release. On the other hand, the formed oriented structure enhances the interaction between the carrier and the cell membrane, significantly promoting transmembrane absorption. Taking nicotinamide as an example, the 3D-printed LLC system of this invention can significantly improve the delivery efficiency and application stability of its water-soluble active ingredients, reducing its potential conversion risk under adverse environments, thereby providing the possibility for implementing personalized nutrition programs.

[0027] In summary, this invention has successfully developed a green, edible delivery technology with the potential for large-scale production by introducing 3D printing technology into the lipid liquid crystal system. This technology not only provides an innovative solution for the intersection of food and medicine, but also lays a solid foundation for the development of a new generation of functional nutrition delivery systems.

[0028] The inventiveness of this invention is reflected in at least the following aspects: (1) This invention is the first to apply 3D printing shear flow field programming technology to lipid lyotropic liquid crystal systems. In the prior art, shear-induced orientation is only found in thermotropic liquid crystal polymer (LCP) systems, and its purpose is to regulate the mechanical properties of structural materials; while this invention applies it to lipid LLC systems, and realizes the release kinetics programming of water-soluble nutrients by regulating the curvature and connectivity of nanochannels.

[0029] (2) The structure-function active programming of the LLC oral delivery system is realized for the first time. Existing pH-responsive LLC delivery systems rely on the passive self-assembly mode that determines the structure by the components, and cannot regulate the mesoscopic structure without changing the formulation; while the present invention realizes the active regulation of LLC structure under the same formulation through 3D printing shearing, producing release behavior and absorption promotion effect that cannot be achieved by passive self-assembly.

[0030] (3) Unexpected synergistic effects were produced. The shear-induced orientation structure of 3D printing not only changed the release kinetics, but also significantly enhanced the redispersibility in intestinal fluid and the cell absorption efficiency. This triple synergistic effect of structure regulation-release control-absorption promotion is something that existing technologies could not have predicted. Attached Figure Description

[0031] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1A polarizing microscope image of the self-assembled, unprinted MO-LLC obtained in Example 1; Figure 2 SAXS plots of self-assembled MO-LLC (Comparative Example 1) and programmed MO-LLC (3D printed 0.16mm MO-LLC and 3D printed 0.34mm MO-LLC in Example 1), where A is Comparative Example 1, and B and C are 3D printed 0.16mm MO-LLC and 3D printed 0.34mm MO-LLC in Example 1, respectively. Figure 3 Different drug-loaded compositions (Comparative Example 2: Nicotinamide emulsion) Figure 3 The emulsion group in Example 1 corresponds to 0.16mm and 3D-0.16mm in the figure; the 3D printed 0.34mm MO-LLC corresponds to 0.34mm and 3D-0.34mm in the figure; Blank corresponds to the concentration change of nicotinamide in the stomach in Example 1 (A), the release curve in the small intestine (B), and the sample recovery rate (C) results. Figure 4 The results of Caco-2 cell uptake tests for nicotinamide on different carriers (emulsion represents Comparative Example 2; 0.16 represents 3D printed 0.16 mm MO-LLC in Example 1; 0.34 represents 3D printed 0.34 mm MO-LLC in Example 1; Blank represents Comparative Example 1; bare drug represents Comparative Example 3); Figure 5 The results of fluorescence imaging detection in different groups of mice at 0, 3, and 6 h are shown in the figure. Figure 5 (Among them, the bare drug is comparative example 3, the emulsion is comparative example 2, Blank LLC is comparative example 1, and 3DLLC is example 1). Detailed Implementation

[0032] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0033] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0034] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0035] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0036] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0037] This invention provides a lipid lyotropic liquid crystal drug delivery composition comprising an oil phase and an aqueous phase; The oil phase is a mixed lipid matrix of monooleic glycerides and fatty acids; The aqueous phase contains surfactants, electrolytes, and active ingredients; When the oil phase and the aqueous phase are mixed, a lyotropic liquid crystal phase is formed. The lyotropic liquid crystal phase has a nanoscale water channel structure, and the active ingredients are distributed in the water channel structure. The lipid lyotropic liquid crystal drug-loaded composition is processed by extrusion. The shear flow field generated during the extrusion process causes the mesoscopic structure of the lyotropic liquid crystal phase to undergo orientation reconstruction.

[0038] In a preferred embodiment of the present invention, the fatty acid is linoleic acid, and the mass ratio of monooleic glyceride to fatty acid in the oil phase is 97:3.

[0039] In a preferred embodiment of the present invention, the surfactant is Pluronic F127, the electrolyte is KCl, the mass percentage concentration of Pluronic F127 in the aqueous phase is 1%, the concentration of KCl is 150 mM, and the pH value of the aqueous phase is 2.0.

[0040] In a preferred embodiment of the present invention, the active ingredient is nicotinamide, and the mass percentage concentration of nicotinamide in the aqueous phase is 0.2%.

[0041] In a preferred embodiment of the present invention, the mass ratio of the oil phase to the water phase is 7:3.

[0042] In a preferred embodiment of the present invention, the lyotropic liquid crystal phase exhibits a hexagonal phase structure under pH conditions of 1.5-3.0, and the nanoscale water channels are one-dimensional water channels; under pH conditions of 6.0-7.4, the hexagonal phase structure undergoes a phase transition, and the connectivity of the water channels increases.

[0043] This invention also provides a method for preparing the above-mentioned lipid lyotropic liquid crystal drug-loaded composition, comprising the following steps: The oil phase was prepared by mixing monooleic glycerides with fatty acids; An aqueous phase is prepared by dissolving surfactants, electrolytes, and active ingredients in water, and the pH is adjusted to acidity. The aqueous phase and oil phase are mixed and homogenized to form a lyotropic liquid crystal phase; The lyotropic liquid crystal phase was extruded, and the shear flow field generated during the extrusion process induced the orientation reconstruction of the mesoscopic structure of the lyotropic liquid crystal phase. After extrusion and standing, a lipid lyotropic liquid crystal drug-loaded composition was obtained. The extrusion process is 3D printing extrusion.

[0044] In a preferred embodiment of the present invention, the nozzle diameter for 3D printing extrusion is 0.16-0.34 mm. For example, a nozzle with a diameter of 0.16 mm or 0.34 mm can be used for 3D printing extrusion. The extrusion pressure is 0.5~1 bar, the printing speed is 15 mm / s, and the layer height is 0.2 mm. The orientation reconstruction of the mesoscopic structure manifests as a transformation of the liquid crystal domains from a random multi-domain structure to an oriented structure, with changes in the curvature, connectivity, and arrangement of the water channels.

[0045] In a preferred embodiment of the present invention, the settling time is 24 hours.

[0046] This invention achieves a fundamental breakthrough in the preparation process of lipid lyotropic liquid crystals by introducing 3D printing, enabling a shift from passive acceptance to active programming of the liquid crystal mesoscopic structure. Compared to unprinted self-assembled samples, MO-LLC samples treated with the high-shear flow field of the 3D printing nozzle exhibit a transformation in their liquid crystal domains from a random multi-domain distribution to a directional oriented structure. This microstructural change leads to a significant performance improvement. Regarding release behavior, the liquid crystal domains of self-assembled samples are randomly arranged, the connectivity of nanochannels is uncontrollable, drug release pathways are random, burst release is prone to occur, and release curves are difficult to predict. In contrast, the oriented structure of the 3D-printed samples results in an ordered arrangement of nanochannels, allowing for precise control of drug diffusion pathways and transforming release kinetics from "uncontrollable" to "programmable." In terms of absorption promotion, the shear-induced oriented structure endows MO-LLC with superior redispersibility in intestinal fluid, resulting in smaller, more uniformly distributed colloidal particles that facilitate interaction with intestinal epithelial cells.

[0047] In summary, this invention achieves active programming of the lipid lyotropic liquid crystal mesostructure from random multi-domain to oriented ordered through 3D printing shear flow field. This structural regulation method endows the carrier system with predictable and designable release behavior, as well as significantly enhanced oral absorption efficiency, fully demonstrating the application value of the design concept of "structure determines function" in the field of functional nutrient delivery.

[0048] For example, the preparation method of the lipid lyotropic liquid crystal drug-loaded composition in this embodiment of the invention includes the following steps: Glyceryl monooleate (MO) and linoleic acid were mixed at a ratio of 97:3 (w / w) and heated until clear to obtain the oil phase. Simultaneously, an aqueous solution containing 1% (w / w) Pluronic F127 and 150 mM KCl was prepared, the pH was adjusted to 2.0 with hydrochloric acid, and 0.2% (w / w) nicotinamide was added. Subsequently, the aqueous and oil phases were mixed at a ratio of 7:3 (w / w) and homogenized at 10,000 rpm for 5 min using a homogenizer to obtain the lyotropic liquid crystal phase (LLC). This lyotropic liquid crystal phase was loaded into a 3D printer and extruded through nozzles with diameters of 0.16 or 0.34 mm, respectively. The high shear flow field within the nozzle induced orientation reconstruction of the liquid crystal mesoscopic structure. After printing, the formulation was allowed to stand at room temperature for 24 hours to allow the liquid crystal structure to fully balance and stabilize, yielding the lipid lyotropic liquid crystal drug-loaded composition (MO-LLC).

[0049] This invention also provides an application of the above-mentioned lipid lyotropic liquid crystal drug-loaded composition in the preparation of an oral delivery system. This oral delivery system utilizes the gastrointestinal pH gradient as an endogenous trigger signal. In the acidic environment of the stomach, the lipid lyotropic liquid crystal drug-loaded composition maintains a hexagonal phase structure to achieve sustained release of the active ingredient. In the neutral or weakly alkaline environment of the intestine, the lipid lyotropic liquid crystal drug-loaded composition undergoes a phase transition to achieve targeted release of the active ingredient. The lipid lyotropic liquid crystal drug-loaded composition forms nano- or submicron-sized colloidal particles in the intestinal environment.

[0050] In this embodiment of the invention, room temperature refers to "25±3℃".

[0051] The technical solution of the present invention will be further illustrated by the following embodiments.

[0052] Example 1 A lipid-lyotropic liquid crystal drug delivery composition is prepared as follows: Glyceryl monooleate and linoleic acid were mixed at a ratio of 97:3 (w / w) and heated until clear to obtain the oil phase. Simultaneously, an aqueous solution containing 1% (w / w) Pluronic F127 and 150 mM KCl was prepared, the pH was adjusted to 2.0 with hydrochloric acid, and 0.2% (w / w) nicotinamide was added. Subsequently, the aqueous and oil phases were mixed at a ratio of 7:3 (w / w) and homogenized at 10,000 rpm for 5 min to obtain the lyotropic liquid crystal phase. This lyotropic liquid crystal phase was loaded into a 3D printer and extruded through nozzles with diameters of 0.16 mm and 0.34 mm, respectively. The high shear flow field within the nozzle induced orientation reconstruction of the liquid crystal mesoscopic structure. After printing, the formulation was allowed to stand at room temperature for 24 hours to allow the liquid crystal structure to fully balance and stabilize, yielding lipid lyotropic liquid crystal drug-loaded compositions with different nozzle diameters, designated as 3D-printed 0.16 mm MO-LLC and 3D-printed 0.34 mm MO-LLC, respectively.

[0053] Comparative Example 1 The self-assembly preparation of lipid-lyotropic liquid crystal drug-loaded compositions specifically includes the following steps: Glyceryl monooleate and linoleic acid were mixed at a ratio of 97:3 (w / w) and heated until clear to obtain an oil phase. Simultaneously, an aqueous solution containing 1% (w / w) Pluronic F127 and 150 mM KCl was prepared, the pH was adjusted to 2.0 with hydrochloric acid, and 0.2% (w / w) nicotinamide was added. Subsequently, the aqueous and oil phases were mixed at a ratio of 7:3 (w / w) and homogenized to form a lyotropic liquid crystal phase, yielding a lipid-lyotropic liquid crystal drug delivery composition, denoted as self-assembled MO-LLC.

[0054] Comparative Example 2 A nicotinamide emulsion is prepared as follows: The nicotinamide emulsion was a W1 / O / W2 (water / oil / water) type. The inner aqueous phase (W1) consisted of 1% (w / w) nicotinamide and 2% (w / w) sodium alginate; the oil phase (O) was a mixture of corn oil and 4.5% (w / w) polyglycerol ricinoleate (PGPR). The primary emulsion (W1 / O) was prepared by high-speed shearing of 70% (w / w) oil phase and 30% (w / w) inner aqueous phase at 12,000 rpm for 2 min. The outer aqueous phase (W2) was a mixed solution of 4% (w / v) whey protein isolate (WPI) and 2% (w / w) sodium alginate. The primary emulsion (20% w / w) and the external aqueous phase (80% w / w) were re-emulsified at 8,000 rpm for 2 min to obtain the W1 / O / W2 type nicotinamide emulsion. The primary emulsion (W1 / O) accounted for 20% of the total mass of the final emulsion, and the external aqueous phase (W2) accounted for 80%. During the preparation process, the pH of each phase solution was adjusted to 7.0 with 0.1 M NaOH or HCl.

[0055] Comparative Example 3 Dissolve 30 mg of nicotinamide directly in 50 g of ultrapure water. Once completely dissolved, the naked drug control solution is obtained.

[0056] Performance testing A suitable amount of the self-assembled, unprinted MO-LLC obtained in Comparative Example 1 was prepared into slices and observed using a polarizing microscope. The polarizing microscope images are shown below. Figure 1 As shown, the sample exhibits obvious birefringence, and the optical texture is a typical mosaic or fan-shaped pattern, confirming that MO-LLC has formed a hexagonal liquid crystal structure.

[0057] To characterize the nanoscale microstructure of the samples, small-angle X-ray scattering (SAXS) was used to test the self-assembled MO-LLC (Comparative Example 1) and programmed MO-LLC (3D-printed 0.16 mm MO-LLC and 3D-printed 0.34 mm MO-LLC in Example 1). The SAXS spectra are shown below. Figure 2 In Example 1, A represents Comparative Example 1, and B and C represent 3D-printed 0.16mm MO-LLC and 0.34mm MO-LLC, respectively. It can be seen that MO can form LLC through thermodynamic self-assembly. After 3D printing, the MO-LLC sample still maintains a hexagonal phase structure, and changes in the nozzle diameter do not affect the crystal shape of the MO-LLC, indicating that the system has good structural stability and process adaptability. The position ratio of the scattering peaks conforms to the characteristic of 1:√3:√4, indicating that the self-assembled MO-LLC has formed a hexagonal phase structure. The programmed MO-LLC obtained by 3D printing retains this liquid crystal phase after shearing, without undergoing a phase transition.

[0058] An in vitro dynamic gastrointestinal digestive system is used to simulate the human digestive process.

[0059] Various samples containing nicotinamide were administered via room temperature water (Comparative Example 2: Nicotinamide emulsion corresponding to the emulsion group; 3D printed 0.16mm MO-LLC in Example 1 corresponding to 0.16 and 3D-0.16mm in the figure; 3D printed 0.34mm MO-LLC corresponding to 0.34 and 3D-0.34mm in the figure; Blank corresponding to Comparative Example 1). Samples were collected periodically in a simulated stomach and terminal small intestine. After centrifugation and microfiltration, the nicotinamide content was determined by high-performance liquid chromatography (HPLC) to calculate its bioavailability. The concentration changes of nicotinamide in the stomach (A), the release curve in the small intestine (B), and the sample recovery rate (C) of different drug-loaded compositions are shown in the figure. Figure 3As can be seen, although the nicotinamide emulsion release concentration of Comparative Example 2 was low in the gastric environment, analysis of the recovery rate data suggests that this was not due to its superior protective effect, but rather to the decomposition of nicotinamide, resulting in a poor actual protective effect. In contrast, the nicotinamide concentration of the 3D-printed MO-LLC in Example 1 was significantly lower than that of the self-assembled sample in Comparative Example 1, demonstrating superior gastric protective performance. Upon entering the intestinal environment, the release rate of the nicotinamide emulsion further accelerated, reaching its peak release within 3 hours, but its recovery rate was only about half, indicating poor overall protective effect, limited by the low total release volume. In comparison, the 3D-printed MO-LLC in Example 1 exhibited superior release performance in the intestine, with higher release efficiency and a recovery rate exceeding 80%, significantly enhancing the protective effect. In the simulated intestinal environment, nicotinamide release was more complete, the release rate was significantly increased, and it exhibited typical pH-responsive sustained-release characteristics. These results demonstrate that the 3D-printed MO-LLC carrier constructed in the embodiments of this invention possesses good drug protection capabilities and intestinal-targeted sustained-release performance. This difference cannot be achieved by simple physical mixing or stirring, indicating that only a confined high-shear flow field within the 3D printing nozzle can achieve the orientation reconstruction of liquid crystal domains and produce the aforementioned significant change in release behavior.

[0060] Absorption experiments were conducted using a Caco-2 cell model (Jiangsu Aidisheng Biotechnology Co., Ltd.). After cells were revived and cultured to a suitable state, they were seeded into 12-well chambers. 0.5 mL of a digested sample containing trypsin inhibitor at a concentration of 5 mmol / L (Comparative Example 1: self-assembled MO-LLC; 3D-printed 0.16 mm MO-LLC and 3D-printed 0.34 mm MO-LLC from Example 1; Comparative Example 2: nicotinamide emulsion; and Comparative Example 3: naked control) was added to the top side of the cells. 1.5 mL of preheated PBS was added to the bottom side, and the cells were incubated at 37°C. 100 μL of sample was taken from the bottom side periodically, and an equal volume of preheated PBS was added. The top side solution was collected after incubation. The samples were diluted, filtered, and analyzed by high-performance liquid chromatography (HPLC). Apparent permeability and absorption rate were calculated. The results of nicotinamide absorption rate tests in Caco-2 cells using different carriers are shown below. Figure 4 and Table 1 ( Figure 4The emulsion represents Comparative Example 2; 0.16 represents the 3D-printed 0.16mm MO-LLC in Example 1; 0.34 represents the 3D-printed 0.34mm MO-LLC in Example 1; Blank represents Comparative Example 1, and bare drug represents Comparative Example 3. It can be seen that the apparent permeability coefficient and absorption rate of the MO-LLC carrier are significantly better than those of the emulsion and bare drug. The 3D printing process in the examples endows MO-LLC with excellent redispersibility in intestinal fluid, enabling it to form small and uniform colloidal particles. This significantly improves nutrient absorption efficiency by promoting cell uptake or membrane fusion. 3D-printed MO-LLC readily undergoes "redispersibility / self-emulsification" in the intestinal fluid environment, forming even smaller nano / submicron colloids, thereby effectively improving the apparent permeability coefficient. Simultaneously, the printed colloidal particles are more easily taken up by cells or fused with cell membranes, and the 3D printing technology allows nutrients to be in a more uniform and stable dispersion state, significantly enhancing the intestinal absorption efficiency and bioavailability of MO-LLC.

[0061] Unlike the random multi-domain structure of self-assembled samples, the oriented structure of 3D-printed samples results in an ordered arrangement of hydrophobic tail chains of liquid crystal domains. This ordered arrangement, when redispersed in intestinal fluid, forms colloidal particles with smaller particle sizes, making them more readily uptaken via passive transport through the Caco-2 cell monolayer membrane and clathrin-mediated endocytosis. This synergistic effect is unattainable using 3D printing technology alone (without LLC) or LLC carriers alone (without 3D printing shearing).

[0062] Table 1. Absorption rate and apparent permeability coefficient of nicotinamide on different carriers Nicotinamide was fluorescently labeled with Cy5 near-infrared fluorescent dye (Ex=650 nm, Em=670 nm) to enable real-time tracking of drug behavior in vivo and to investigate the protective effects of different carriers on the drug. Specifically, drug-loaded compositions were prepared according to the methods in Comparative Examples 1-3 and Example 1 (3D printing of 0.16 mm MO-LLC). Fifteen SPF-grade C57 female mice, 6-8 weeks old and weighing 18-22 g, were used for in vivo experiments. The mice were randomly divided into 4 groups. Before the experiment, the mice were fasted for 12 h, weighed, and then administered the drug at a uniform dose of 0.1 mL / 10 g body weight. The mice were anesthetized by isoflurane inhalation and administered the drug by gavage. Fluorescence imaging was performed using a small animal in vivo near-infrared fluorescence imager at 0, 3, and 6 h after administration. After the detection, the mice were placed on a warming mat for recovery. The fluorescence imaging results of different groups of mice at 0, 3, and 6 h are shown in the figure. Figure 5(Among them, the bare drug was Comparative Example 3, the emulsion was Comparative Example 2, Blank LLC was Comparative Example 1, and 3DLLC was Example 1.) It can be seen that the Cy5-nicotinamide 3D-printed (0.16mm)-LLC group still showed a significant fluorescence signal 6 h after administration, while the fluorescence intensity of other groups (bare drug group, emulsion group, and Blank LLC carrier group) had significantly decreased at the same time. Specifically, the bare drug group had the strongest fluorescence signal at the initial stage of administration (0 h), but the signal decayed rapidly over time, becoming almost invisible by 3 h, indicating that the free drug was cleared from the body very quickly and lacked effective retention capacity. The fluorescence intensity of the W1 / O / W2 emulsion group and the unprinted LLC group was weaker than that of the 3D-printed LLC group at 3 h, suggesting that although they could delay drug release to some extent, their protective effect was limited. In contrast, the 3D-printed LLC group exhibited the best sustained-release properties. The printed LLC better encapsulated the drug in its hydrophilic channels, effectively reducing the burst release and degradation of the drug in the gastrointestinal environment, and showed good potential for drug protection and sustained release.

[0063] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a lipid-lyotropic liquid crystal drug-loaded composition, characterized in that, Includes the following steps: The oil phase was prepared by mixing monooleic glycerides with fatty acids; An aqueous phase is prepared by dissolving surfactants, electrolytes, and active ingredients in water, and the pH is adjusted to acidity. The aqueous phase and the oil phase are mixed and homogenized to form a lyotropic liquid crystal phase. The lyotropic liquid crystal phase is extruded, and the shear flow field generated during the extrusion process induces the orientation reconstruction of the mesoscopic structure of the lyotropic liquid crystal phase. After extrusion, the phase is allowed to stand to obtain the lipid lyotropic liquid crystal drug-loaded composition. The extrusion process is 3D printing extrusion, and the nozzle diameter of the 3D printing extrusion is 0.16-0.34 mm.

2. The method for preparing the lipid lyotropic liquid crystal drug-loaded composition according to claim 1, characterized in that, The fatty acid is linoleic acid, and the mass ratio of monooleic glyceride to fatty acid in the oil phase is 97:

3.

3. The method for preparing the lipid lyotropic liquid crystal drug-loaded composition according to claim 1, characterized in that, The surfactant is Pluronic F127, the electrolyte is KCl, the mass concentration of Pluronic F127 in the aqueous phase is 1%, and the concentration of KCl is 150 mM.

4. The method for preparing the lipid lyotropic liquid crystal drug-loaded composition according to claim 1, characterized in that, The pH value of the aqueous phase is 2.

0.

5. The method for preparing the lipid lyotropic liquid crystal drug-loaded composition according to claim 1, characterized in that, The active ingredient is a water-soluble active substance, and the mass concentration of the active ingredient in the aqueous phase is 0.2%.

6. The method for preparing the lipid lyotropic liquid crystal drug-loaded composition according to claim 1, characterized in that, The mass ratio of the oil phase to the water phase is 7:

3.

7. The method for preparing the lipid lyotropic liquid crystal drug-loaded composition according to claim 1, characterized in that, The lyotropic liquid crystal phase has a nanoscale water channel structure, and the active ingredient is distributed in the water channel structure; The shear flow field generated during the extrusion processing of the lipid lyotropic liquid crystal drug-loaded composition causes orientation reconstruction of the mesotropic liquid crystal phase.

8. The method for preparing the lipid lyotropic liquid crystal drug-loaded composition according to claim 7, characterized in that, The lyotropic liquid crystal phase exhibits a hexagonal phase structure under pH conditions of 1.5-3.0, and the nanoscale water channels are one-dimensional water channels; under pH conditions of 6.0-7.4, the hexagonal phase structure undergoes a phase transition, and the connectivity of the water channels increases.

9. A lipid-lyotropic liquid crystal drug-loaded composition prepared by the preparation method according to any one of claims 1-8.

10. The use of the lipid-lyotropic liquid crystal drug delivery composition of claim 9 in the preparation of an oral delivery system, characterized in that, The oral delivery system utilizes the gastrointestinal pH gradient as an endogenous trigger signal. In the acidic environment of the stomach, the lipid-lyotropic liquid crystal drug-loaded composition maintains a hexagonal phase structure to achieve sustained release of the active ingredient. In the neutral or weakly alkaline environment of the intestine, the lipid-lyotropic liquid crystal drug-loaded composition undergoes a phase transition to achieve targeted release of the active ingredient. The lipid-lyotropic liquid crystal drug-loaded composition forms nano- or submicron-sized colloidal particles in the intestinal environment.

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