Lipidic lyotropic liquid crystals: Insights on biomedical applications

Isotretinoin-Loaded Topical Lipid Liquid Crystal for the Treatment of Acne: In-Vitro and In-Vivo Evaluations

Effective acne treatment is critical due to its profound impact on physical and psychological well-being. It was shown that severe systemic side effects, including teratogenicity, ovarian reserve reduction, depression, dry skin, hypertriglyceridemia, and intracranial hypertension limited oral isotretinoin usage. Therefore, this study addresses these challenges by developing isotretinoin-loaded lipid liquid crystal (LLC-IT) nanoparticles for topical application, aiming to enhance localized delivery while minimizing systemic exposure. LLC-IT nanoparticles were prepared using a top-down method and evaluated for their physicochemical properties, photostability, cytotoxicity, antimicrobial activity, in-vitro drug release, and in-vivo therapeutic efficacy. A testosterone-induced acne mouse model was used to compare LLC-IT treatment with untreated and commercial isotretinoin gel-treated groups. LLC-IT nanoparticles exhibited a uniform particle size (69.57 ± 0.51 nm), low polydispersity index (0.264 ± 0.01), and stable zeta potential (- 19.3 ± 0.2 mV). High encapsulation efficiency (95% ± 3) and effective loading capacity (1.15% ± 0.13) were achieved. Drug release was diffusion-controlled with minimal UV-induced degradation. Stability assessments over 12 months confirmed consistent properties across varying storage temperatures. LLC-IT displayed significant antibacterial activity and reduced skin irritation in Draize tests compared to commercial gels. In-vivo, LLC-IT reduced inflammation significantly more than untreated or commercial gel-treated groups, indicating enhanced therapeutic efficacy of LLC-IT formulation. The isotretinoin-loaded lipid liquid crystal formulation shows superior stability and efficacy with reduced side effects compared to conventional treatments, offering a more effective and patient-friendly solution, as well as a promising alternative for industrial production in acne management.

pH-sensitive lyotropic liquid crystal beads designed for oral zero-order extended drug release

The present study introduces a novel formulation approach for utilizing Lyotropic Liquid Crystals (LLCs) as sustained oral delivery systems. For this purpose, a novel bottom-up fabrication process was developed, enabling the casting of LLC beads with precise control over their diameter. Predetermining the effective diffusional interfacial surface of the beads enables regulation of the release rate of solubilized drugs from the LLCs. To prevent bead coalescence throughout shelf life, the LLC beads are embedded in a heat-sensitive gelatin-chitosan coacervate. Additionally, the study focuses on LLC beads formulated as pH-responsive systems, designed to attenuate the Higuchian primary diffusional burst in a gastric environment while enhancing the release of the solubilized load at an elevated pH (6.4). To demonstrate the applicability of the pH-responsive systems, the LLC beads were loaded with a lipophilic low water solubility (< 5 µg/mL) model drug, Celecoxib (CLXB). Although the water solubility of CLXB is not pH dependent, the Higuchian release constant of CLXB increased from 9.31 at pH 1.5 to 15.03 at pH 6.4. The pH dependency of CLXB release was achieved by the co-solubilization of additional compounds in the LLC structure, creating a pH-dependent environment that influences both the LLC structure and the release of the co-solubilized compounds. The enhanced release of CLXB in an elevated pH environment enables gaining a zero-order (R2 > 0.99) sustained release profile extending beyond 10 h in a release medium simulating the gastrointestinal (GI) tract environment. Additionally, the study investigated the association between the release of co-solubilized compounds and the micellar structure using techniques such as small-angle X-ray diffraction, nuclear magnetic resonance, and electron paramagnetic resonance. The results revealed a co-dependent relationship between the release of lipophilic compounds and changes of the LLC's curvature at different pH levels, suggesting that a compensatory mechanism operates between these two processes. These insights, combined with the innovative bottom-up fabrication method for LLC beads, provide valuable tools for controlling the release of lipophilic compounds from LLCs and for enhancing their effectiveness as controlled oral delivery systems.

Non-ionic surfactant self-assembly in calcium nitrate tetrahydrate and related salts

Self-assembly of amphiphilic molecules can take place in extremely concentrated salt solutions, such as inorganic molten salt hydrates or hydrous melts. The intermolecular interactions governing the organization of amphiphilic molecules under such extreme conditions are not yet fully understood. In this study, we investigated the specific effects of ions on the self-assembly of the non-ionic surfactant C12H25(OCH2CH2)10OH (C12E10) under extreme salt concentrations, using calcium nitrate tetrahydrate as a reference. The mixtures of Ca(NO3)2·4H2O and C12E10 displayed lyotropic (H1 and I1) and micellar phases, in contrast to CaCl2·xH2O-C12E10 or CaBr2·xH2O-C12E10 mixtures where mesostructurally ordered salt-surfactant complexes were observed. The Ca(NO3)2·4H2O-C12E10 system was thoroughly investigated by constructing its binary phase diagram and performing thermal and spectral comparisons with other salt hydrates. The Ca(NO3)2 system displayed significantly higher isotropization temperatures than zinc, aluminium, and lithium nitrate systems. ATR-FTIR analysis revealed that Ca2+ primarily interacts with the surfactant head groups through ion-dipole interactions, while these interactions were less pronounced with other cations. The results show that an intermediate hydration/coordination energy of the metal ion can lead to stronger metal-surfactant interactions and thermally more stable liquid crystals. Comparison between the Ca(NO3)2, CaCl2, and CaBr2 systems suggests that reduced ion pair formation enhances the interactions between Ca2+ and oxyethylene groups, leading to the salting-out of salt-surfactant complexes. Despite its low water content and strong intermolecular interactions, the Ca(NO3)2·xH2O-C12E10 system exhibited an electrical conductivity of up to 1.0 × 10-3 S cm-1 with 4 water molecules per salt, making it a promising medium for electrochemical applications.

Azelaic acid-based lyotropic liquid crystals gel for acne vulgaris: Formulation optimization, antimicrobial activity and dermatopharmacokinetic study

The proposed study aimed to develop a topical gel containing azelaic acid (AZA)-based lyotropic liquid crystals (LLCs) for the treatment of acne vulgaris. AZA-based LLCs were optimized by varying Poloxamer-407 and polyvinyl alcohol concentration using a central composite design, which showed that both independent variables had a significant effect on the formulation. The highest desirable trial of AZA-based LLCs (Batch-7) containing 300 mg poloxamer-407 and 100 mg polyvinyl alcohol depicted the particle size, zeta potential, and entrapment efficiency of 184.2 nm, -16.1 mV, and 79.96 %, respectively. TEM images confirmed the globular vesicles of LLCs, and ATR-FTIR and DSC results confirmed the compatibility of formulation excipients. In vitro, the release of AZA, AZA-based LLCs, AZA-based LLC gel, and marketed gel showed a release of 23.29, 95.24, 91.07 and 59.88 %, respectively, after 24 h in phosphate buffer pH 6.8. Ex vivo release of AZA-based LLC gel displayed an 86.56 % release after 24 h. The antimicrobial activity of AZA-based LLC gel exhibited a comparable efficacy with marketed gel against Cutibacterium acnes, Staphylococcus epidermis and Staphylococcus aureus. The acute dermal irritation study indicated excellent safety and skin compatibility of AZA-based LLC gel without any erythema and edema. The dermatopharmacokinetic study displayed an enhanced drug retention for AZA-based LLC gel (146.121 ± 21.13 µg/cm2) than marketed gel (58.58 ± 15.95 µg/cm2) in the dermal layer, which would improve its therapeutic effect. These outcomes proved that AZA-based LLC gel has the potential to enhance skin penetration and retention for effective management of acne vulgaris.

Lyotropic liquid crystal emulsions of LAVR-289: Influence of internal mesophase structure on cytotoxicity and in-vitro antiviral activity

Emerging and reemerging viruses pose significant public health threats, underscoring the urgent need for new antiviral drugs. Recently, a novel family of antiviral acyclic nucleoside phosphonates (ANP) composed of a 4-(2,4-diaminopyrimidin-6-yl)oxy-but-2-enyl phosphonic acid skeleton (O-DAPy nucleobase) has shown promise. Among these, LAVR-289 stands out for its potent inhibitory effects against various DNA viruses. Despite its efficacy, LAVR-289s poor water solubility hampers effective drug delivery. To address this, innovative delivery systems utilizing lipidic derivatives have been explored for various administration routes. Submicron lyotropic liquid crystals (LLCs) are particularly promising drug carriers for the encapsulation, protection, and delivery of lipophilic drugs like LAVR-289. This study focuses on developing submicron-sized lipid mesophase dispersions, including emulsified L2 phase, cubosomes, and hexosomes, by adjusting lipidic compounds such as Dimodan® U/J, Lecithins E80, and Miglyol® 812 N. These formulations aim to enhance the solubility and bioavailability of LAVR-289. In vitro evaluations demonstrated that LAVR-289-loaded LLCs at a concentration of 1 µM efficiently inhibited vaccinia virus in infected human cells, with no observed cytotoxicity. Notably, hexosomes exhibited the most favorable antiviral outcomes, suggesting that the internal mesophase structure plays a critical role in optimizing the therapeutic efficacy of this drug class.

Recent Advances in Ocular Drug Delivery: Insights into Lyotropic Liquid Crystals

Background/Objectives: This review examines the evolution of lyotropic liquid crystals (LLCs) in ocular drug delivery, focusing on their ability to address the challenges associated with traditional ophthalmic formulations. This study aims to underscore the enhanced bioavailability, prolonged retention, and controlled release properties of LLCs that significantly improve therapeutic outcomes. Methods: This review synthesizes data from various studies on both bulk-forming LLCs and liquid crystal nanoparticles (LCNPs). It also considers advanced analytical techniques, including the use of machine learning and AI-driven predictive modeling, to forecast the phase behavior and molecular structuring of LLC systems. Emerging technologies in biosensing and real-time diagnostics are discussed to illustrate the broader applicability of LLCs in ocular health. Results: LLCs are identified as pivotal in promoting targeted drug delivery across different regions of the eye, with specific emphasis on the tailored optimization of LCNPs. This review highlights principal categories of LLCs used in ocular applications, each facilitating unique interactions with physiological systems to enhance drug efficacy and safety. Additionally, novel applications in biosensing demonstrate LLCs' capacity to improve diagnostic processes. Conclusions: Lyotropic liquid crystals offer transformative potential in ocular drug delivery by overcoming significant limitations of conventional delivery methods. The integration of predictive technologies and biosensing applications further enriches the utility of LLCs, indicating a promising future for their use in clinical settings. This review points to continued advancements and encourages further research in LLC technology to maximize its therapeutic benefits.

Injectable long-acting formulations (ILAFs) and manufacturing techniques

INTRODUCTION

Most therapeutics delivered using short-acting formulations need repeated administration, which can harm patient compliance and raise failure risks related to inconsistent treatment. Injectable long-acting formulations (ILAFs) are controlled/sustained-release formulations fabricated to deliver active pharmaceutical ingredients (APIs) and extend their half-life over days to months. Longer half-lives of ILAFs minimize the necessity for frequent doses, increase patient compliance, and reduce the risk of side effects from intravenous (IV) infusions. Using ILAF technologies, the immediate drug release can also be controlled, thereby minimizing potential adverse effects due to high initial drug blood concentrations.

AREA COVERED

In this review, we have discussed various ILAFs, their physiochemical properties, fabrication technologies, advantages, and practical issues, as well as address some major challenges in their application. Especially, the approved ILAFs are highlighted.

EXPERT OPINION

ILAFs are sustained-release formulations with extended activity, which can improve patient compliance. ILAFs are designed to deliver APIs like proteins and peptides and extend their half-life over days to months. The specific properties of each ILAF preparation, such as extended-release and improved drug targeting capabilities, make them an effective approach for precise and focused therapy. Furthermore, this is especially helpful for biopharmaceuticals with short biological half-lives and low stability since most environmental conditions can protect them from sustained-release delivery methods.

Small-angle X-ray and neutron scattering applied to lipid-based nanoparticles: Recent advancements across different length scales

Lipid-based nanoparticles (LNPs), ranging from nanovesicles to non-lamellar assemblies, have gained significant attention in recent years, as versatile carriers for delivering drugs, vaccines, and nutrients. Small-angle scattering methods, employing X-rays (SAXS) or neutrons (SANS), represent unique tools to unveil structure, dynamics, and interactions of such particles on different length scales, spanning from the nano to the molecular scale. This review explores the state-of-the-art on scattering methods applied to unveil the structure of lipid-based nanoparticles and their interactions with drugs and bioactive molecules, to inform their rational design and formulation for medical applications. We will focus on complementary information accessible with X-rays or neutrons, ranging from insights on the structure and colloidal processes at a nanoscale level (SAXS) to details on the lipid organization and molecular interactions of LNPs (SANS). In addition, we will review new opportunities offered by Time-resolved (TR)-SAXS and -SANS for the investigation of dynamic processes involving LNPs. These span from real-time monitoring of LNPs structural evolution in response to endogenous or external stimuli (TR-SANS), to the investigation of the kinetics of lipid diffusion and exchange upon interaction with biomolecules (TR-SANS). Finally, we will spotlight novel combinations of SAXS and SANS with complementary on-line techniques, recently enabled at Large Scale Facilities for X-rays and neutrons. This emerging technology enables synchronized multi-method investigation, offering exciting opportunities for the simultaneous characterization of the structure and chemical or mechanical properties of LNPs.

Lyotropic liquid crystalline phases: Drug delivery and biomedical applications

Liquid crystal (LC)-based nanoformulations may efficiently deliver drugs and therapeutics to targeted biological sites. Lyotropic liquid crystalline phases (LLCPs) have received much interest in recent years due to their unique structural characteristics of both isotropic liquids and crystalline solids. These LLCPs can be utilized as promising drug delivery systems to deliver drugs, proteins, peptides and vaccines because of their improved drug loading, stabilization, and controlled drug release. The effects of molecule shape, microsegregation, and chirality are very important in the formation of liquid crystalline phases (LCPs). Homogenization of self-assembled amphiphilic lipids, water and stabilizers produces LLCPs with different types of mesophases, bicontinuous cubic (cubosomes) and inverse hexagonal (hexosomes). Moreover, many studies have also shown higher bioadhesivity and biocompatibility of LCs due to their structural resemblance to biological membranes, thus making them more efficient for targeted drug delivery. In this review, an outline of the engineering aspects of LLCPs and polymer-based LLCPs is summarized. Moreover, it covers parenteral, oral, transdermal delivery and medical imaging of LC in targeting various tissues and is discussed with a scope to design more efficient next-generation novel nanosystems. In addition, a detailed overview of advanced liquid crystal-based drug delivery for vaccines and biomedical applications is reviewed.

Transdermal administration of ibuprofen-loaded hexagonal liquid crystal gel for enhancement of drug concentration in the uterus: in vitro and in vivo evaluation

Primary dysmenorrhea is a common disease in women, and oral administration of Ibuprofen (IBU) is associated with first-pass effects and gastrointestinal irritation. Here, we developed ibuprofen-loaded hexagonal liquid crystal (IBU HLC) gel for transdermal administration. In this study, the structure of prepared IBU HLC was characterized using polarizing microscopey (PLM) and small angle X ray diffraction (SAXS). In vitro drug release behavior and percutaneous penetration were investigated, and drug transdermal behavior was observed by confocal laser scanning microscope (CLSM). Finally, the pharmacokinetic profile and tissue distribution were investigated after transdermal administration. The PLM and SAXS results showed that the inner structure of IBU HLC was hexagonal phase. Moreover, in vitro release, skin permeation and CLSM demonstrated that IBU HLC had an excellent sustained-release effect, and a good transdermal penetration effect accompanied by the combination of multiple percutaneous routes. Pharmacokinetic studies indicated that IBU entered the blood circulation through abdominal transdermal administration in small amounts, mainly entering the uterus, and had a certain targeting ability. In conclusion, the IBU HLC gel would be a promising sustained-release preparation for transdermal administration to relieve dysmenorrhea with a significant drug concentration in the uterus.