Pharmaceutical liquid crystals: the relevance of partially ordered systems

The Impact of Phospholipid-Based Liquid Crystals' Microstructure on Stability and Release Profile of Ascorbyl Palmitate and Skin Performance

The drug delivery potential of liquid crystals (LCs) for ascorbyl palmitate (AP) was assessed, with the emphasis on the AP stability and release profile linked to microstructural rearrangement taking place along the dilution line being investigated by a set of complementary techniques. With high AP degradation observed after 56 days, two stabilization approaches, i.e., the addition of vitamin C or increasing AP concentration, were proposed. As a rule, LC samples with the lowest water content resulted in better AP stability (up to 52% of nondegraded AP in LC1 after 28 days) and faster API release (~18% in 8 h) as compared to the most diluted sample (29% of nondegraded AP in LC8 after 28 days, and up to 12% of AP released in 8 h). In addition, LCs exhibited a skin barrier-strengthening effect with up to 1.2-fold lower transepidermal water loss (TEWL) and 1.9-fold higher skin hydration observed in vitro on the porcine skin model. Although the latter cannot be linked to LCs' composition or specific microstructure, the obtained insight into LCs' microstructure contributed greatly to our understanding of AP positioning inside the system and its release profile, also influencing the overall LCs' performance after dermal application.

Bio-synthesis, purification and structural analysis of Cyclosporine-A produced by Tolypocladium inflatum with valorization of agro-industrial wastes

Cyclosporine A (CyA) holds significant importance as a strategic immunosuppressive drug for organ transplant patients. In this study, we aimed to produce pure and cost-effective Cyclosporine A (CyA) by fermenting a culture medium containing dairy sludge, using Tolypocladium inflatum PTCC 5253. Following the fermentation stage, ethyl acetate extraction and fast protein liquid chromatography were employed for sample purification. The initial evaluation of the effectiveness of CyA obtained from these processes was performed through bioassay, wherein the antimicrobial clear zone diameter was found to be larger compared to the sample obtained from the fermentation culture. The concentration of CyA was determined using high-performance liquid chromatography, yielding values of 334 mg/L, 456 mg/L, and 578 mg/L for the fermented, extracted, and purified samples, respectively. Further analysis utilizing liquid chromatography tandem mass spectrometry (LC/MS/MS) confirmed a purity of 91.9% and proper agreement with the standard sample based on the ion intensity of Z/m 1205. To validate the structure of CyA, nuclear magnetic resonance spectroscopy, Fourier-transform infrared (FT-IR), and Raman spectroscopy were employed. X-ray diffraction and differential scanning calorimetry analyses demonstrated that the purified CyA exhibited a crystal structure similar to the standard sample, characterized by two broad peaks at 2θ = 9° and 20°, and comparable glass transition temperatures (57-68 °C for the purified sample; 53-64 °C for the standard sample). Dynamic light scattering analysis confirmed a uniform particle size distribution in both the purified and standard samples. The zeta potentials of the purified and standard samples were determined to be - 25.8 ± 0.16 and - 23.63 ± 0.12 mV, respectively. Our results demonstrate that dairy sludge can serve as a suitable culture medium for the production of (CyA).

Sustain-release lipid-liquid crystal formulations of pexiganan against Helicobacter pylori infection: in vitro evaluation in C57BL/6 mice

INTRODUCTION

The Gram-negative bacterium Helicobacter pylori, H. pylori, is associated with significant digestive disorders. However, the effectiveness of bacterial eradication is declining due to drug resistance. A potent anti-H. pylori activity is shown by the natural antimicrobial peptide pexiganan.

OBJECTIVE

The current study aimed to evaluate the effectiveness of pexiganan and its lipid-liquid crystals (LLCs) in inducing Helicobacter pylori in mice.

METHODS

In this experimental study, H. pylori infection was first induced in C57BL/6 mice. Secondly, the antibacterial efficacy of pexiganan and its LLCs formulations was investigated to eliminate H. pylori infection.

RESULTS

The H. pylori infection could not be completely eradicated by pexiganan peptide alone. However, incorporating pexiganan within the LLC formulation resulted in an increased elimination of H. pylori. Under the H&E strain, the pexiganan-LLCs formulation revealed minimal mucosal alterations and a lower amount of inflammatory cell infiltration in the stomach compared to the placebo.

CONCLUSION

Clarithromycin was more effective than pexiganan at all tested concentrations. Furthermore, the pexiganan-loaded LLCs exhibited superior efficacy in curing H. pylori infection in a mouse model compared to pexiganan alone. This formulation can enhance H. pylori clearance while mitigating the adverse effects, typically associated with conventional drugs, leading to a viable alternative to current treatment options.

Asymmetric Pairing of Cholesteric Liquid Crystal Droplets for Programmable Photonic Cross-Communication

The photonic cross-communication between photonic droplets has provided complex color patterns through multiple reflections, potentially serving as novel optical codes. However, the cross-communication is mostly restricted to symmetric pairs of identical droplets. Here, a design rule is reported for the asymmetric pairing of two distinct droplets to provide bright color patterns through strong cross-communication and enrich a variety of optical codes. Cholesteric liquid crystal (CLC) droplets with different stopband positions and sizes are paired. The brightness of corresponding color patterns is maximized when the pairs are selected to effectively guide light along the double reflection path by stopbands of two droplets. The experimental results are in good agreement with a geometric model where the blueshift of stopbands is better described by the angles of refraction rather than reflection. The model predicts the effectiveness of pairing quantitatively, which serves as a design rule for programming the asymmetric photonic cross-communication. Moreover, three distinct droplets can be paired in triangular arrays, where all three cross-communication paths yield bright color patterns when three droplets are selected to simultaneously satisfy the rule. It is believed that asymmetric pairing of distinct CLC droplets opens new opportunities for programmable optical encoding in security and anti-counterfeiting applications.

Paradigm of lyotropic liquid crystals in tissue regeneration

The liquid crystalline phase has attracted tremendous attention from researchers across the globe due to its intriguing properties. In this article, we enumerate the different classes of liquid crystals. Lyotropic liquid crystals (LLCs) exhibit their liquid crystalline nature based on the surrounding solvent media, which opens novel horizons in drug delivery and tissue regeneration. The advantages of LLCs in the said fields and the thermodynamic mechanistic insights responsible for their structural stabilization have been conveyed. Various fabrication and characterization techniques, along with factors influencing the formation of LLCs, have been discussed. Applications in novel therapeutic avenues like bone extracellular matrix, cardiac remodeling, wound management, and implants have been unveiled. Also, regulatory considerations, patent, and clinical portfolios to circumvent the hurdles of clinical translation have been discussed. LLCs could be a promising approach in diverse avenues of tissue regeneration.

Designing photonic microparticles with droplet microfluidics

Photonic materials with a periodic change of refractive index show unique optical properties through wavelength-selective diffraction and modulation of the optical density of state, which is promising for various optical applications. In particular, photonic structures have been produced in the format of microparticles using emulsion templates to achieve advanced properties and applications beyond those of a conventional film format. Photonic microparticles can be used as a building block to construct macroscopic photonic materials, and the individual microparticles can serve as miniaturized photonic devices. Droplet microfluidics enables the production of emulsion drops with a controlled size, composition, and configuration that serve as the optimal confining geometry for designing photonic microparticles. This feature article reviews the recent progress and current state of the art in the field of photonic microparticles, covering all aspects of microfluidic production methods, microparticle geometries, optical properties, and applications. Two distinct bottom-up approaches based on colloidal assembly and liquid crystals are, respectively, discussed and compared.

A review of tunable photonics: Optically active materials and applications from visible to terahertz

The next frontier of photonics is evolving into reconfigurable platforms with tunable functions to realize the ubiquitous application. The dynamic control of optical properties of photonics is highly desirable for a plethora of applications, including optical communication, dynamic display, self-adaptive photonics, and multi-spectral camouflage. Recently, to meet the dynamic response over broad optical bands, optically active materials have been integrated with the diverse photonic platforms, typically in the dimension of micro/nanometer scales. Here, we review recent advances in tunable photonics with controlling optical properties from visible to terahertz (THz) spectral range. We propose guidelines for designing tunable photonics in conjunction with optically active materials, inherent in wavelength characteristics. In particular, we devote our review to their potential uses for five different applications: structural coloration, metasurface for flat optics, photonic memory, thermal radiation, and terahertz plasmonics. Finally, we conclude with an outlook on the challenges and prospects of tunable photonics.

Lyotropic liquid crystals for parenteral drug delivery

The necessity for long-term treatments of chronic diseases has encouraged the development of novel long-acting parenteral formulations intending to improve drug pharmacokinetics and therapeutic efficacy. Lately, one of the novel approaches has been developed based on lipid-based liquid crystals. The lyotropic liquid crystal (LLC) systems consist of amphiphilic molecules and are formed in presence of solvents with the most common types being cubic, hexagonal and lamellar mesophases. LC injectables have been recently developed based on polar lipids that spontaneously form liquid crystal nanoparticles in aqueous tissue environments to create the in-situ long-acting sustained-release depot to provide treatment efficacy over extended periods. In this manuscript, we have consolidated and summarized the various type of liquid crystals, recent formulation advancements, analytical evaluation, and therapeutic application of lyotropic liquid crystals in the field of parenteral sustained release drug delivery.

Comparison of lipid liquid crystal formulation and Vivitrol® for sustained release of Naltrexone: In vitro evaluation and pharmacokinetics in rats

Camurus' FluidCrystal® injection depot is a lipid liquid crystal (LLC) phase formation-based method, comprising of glycerol dioleate (GDO) and soy phosphatidylcholine (SPC), together with minute quantities of N-methyl-2-pyrrolidone solvent (NMP). The present study aimed to develop a method for LLC using sorbitan monooleate (LLC-SMO) instead of GDO to prepare a one-month sustained-release formulation of naltrexone (NTX) that is applied for the treatment of autism and treating alcohol dependence. The optical characteristics of the LLC were assessed by polarizing light microscopy (PLM) to reveal the presence of lamellar, hexagonal, and cubic mesophases. Furthermore, in vitro release of NTX and NMP, degradation, pharmacokinetics, and histopathology of LLC-GDO and LLC-SMO in rats were evaluated and compared to those of Vivitrol®. The PLM images revealed that the structure of LLC-SMO is hexagonal, similar to LLC-GDO. The in vitro release of NTX and its pharmacokinetic results in rats indicted that the LLC-SMO system is more uniform than LLC-GDO and Vivitrol® during 35 days. Histopathological results of LLC-GDO and LLC-SMO confirmed the biocompatibility of our LLC delivery systems. Taken together these data demonstrate that the LLC-SMO-based method, was efficient enough to sustain the release of NTX in vitro and in vivo, confirming the biocompatible nature of this delivery system.

Nanotechnology-based Drug Delivery Systems as Potential for Skin Application: A Review

Administration of substances through the skin represents a promising alternative, in relation to other drug administration routes, due to its large body surface area, in order to offer ideal and multiple sites for drug administration. In addition, the administration of drugs through the skin avoids the first-pass metabolism, allowing an increase in the bioavailability of drugs, as well as reducing their side effects. However, the stratum corneum (SC) comprises the main barrier of protection against external agents, mainly due to its structure, composition and physicochemical properties, becoming the main limitation for the administration of substances through the skin. In view of the above, pharmaceutical technology has allowed the development of multiple drug delivery systems (DDS), which include liquid crystals (LC), cubosomes, liposomes, polymeric nanoparticles (PNP), nanoemulsions (NE), as well as cyclodextrins (CD) and dendrimers (DND). It appears that the DDS circumvents the problems of drug absorption through the SC layer of the skin, ensuring the release of the drug, as well as optimizing the therapeutic effect locally. This review aims to highlight the DDS that include LC, cubosomes, lipid systems, PNP, as well as CD and DND, to optimize topical skin therapies.

Development of macroscopically ordered liquid crystalline hydrogels from biopolymers with robust antibacterial activity for controlled drug delivery applications

Macroscopically ordered liquid crystalline hydrogel with antibacterial activity for controlled drug delivery applications.

Bioresponsive nanostructured systems for sustained naltrexone release and treatment of alcohol use disorder: Development and biological evaluation

In this study, microemulsions capable of transforming into nanostructured hexagonal phase gels in vivo upon uptake of biological fluids for naltrexone prolonged release were investigated as a strategy for management of alcohol use disorder (AUD). Microemulsions were prepared using monoolein, tricaprylin, water and propylene glycol; after preliminary characterization, one formulation was selected, which contained 55% of monoolein-tricaprylin (M-55). This microemulsion displayed size below 200 nm and Newtonian rheological behavior. Liquid crystalline gels formed in vitro upon 8 h of contact with water following a second order kinetics. After 120 h, <50% of naltrexone was released in vitro independently on drug loading (5 or 10%). In vivo, gels formed within 24 h of M-55 subcutaneous administration, and persisted locally for over 30 days providing slow release of the fluorescent marker Alexa fluor compared to a solution. Using the conditioned place preference paradigm, a test used to measure drug's rewarding effects, a single dose of M-55 containing 5% naltrexone reduced the time spent in the ethanol-paired compartment by 1.8-fold compared to saline; this effect was similar to that obtained with daily naltrexone injections, demonstrating the formulation efficacy and its ability to reduce dosing frequency. A more robust effect was observed following administration of M-55 containing 10% of naltrexone, which was compatible with aversion. These results support M-55 as a platform for sustained release of drugs that can be further explored for management of AUD to reduce dosing frequency and aid treatment adherence.

The involvement of liquid crystals in multichannel implanted neurostimulators, hearing and ENT infections, and cancer

Liquid crystals (LCs) consist of assemblies of molecules, between one and tens of nanometers, grouped in identifiable cohorts according to orientation and structure, which is often lamellar with varying chirality. The term liquid phase (Lo phase) designates certain such mesophases. This variety in geometry corresponds to a variety of functions. Some molecules, both organic and inorganic, used in applied engineering, and association with LCs confer new properties. Applying these aspects of LCs in manufacturing implantable material is a growing technology, especially in the interfaces of differentiated multichannel electro-neurostimulation. We highlight the involvement of LCs in the head and neck region, and the role mesophases play in outer hair cell electromotility (mechanotransduction). We summarize implications of LCs this for multichannel electroneurostimulation implant engineering, and highlight their role importance of LCs in early oncogenic process, HPV, and latency in (Epstein-Barr) and other pathogens. Our approach should help give rise to new therapeutic perspectives. Focusing on upstream nanometric phenomena needs to take on board classic determinism, quantum probability, and statistical complexity.

Some observations on the liquid crystalline and gel behaviors of aqueous dispersions of a prodrug

BMS-830216 is a diprotic acid prodrug of two pK_a values (<2 and 6.8) with high apparent solubility at pH ≥ 7. At ∼ pH 4 solutions of BMS-830216 appear to be surface active, in which their surface tension can be reduced from 72 to 65 dynes when its concentrations is above the critical aggregation concentration (CAC∼0.2 mM). Additionally, at this pH, BMS-830216 tends to form liquid crystalline phases (at ≥ 2 mg/mL) in acetate buffer when using tris salt. Furthermore, after raising the concentration beyond 20 mg/g, formation of gel-like dispersions was noted. These gel-like dispersions exhibited a strong elastic strength, significantly impacting the dissolution behavior of the tris salt. Mechanistically, it is likely that BMS-830216 tris salt in solution first forms a lamellar phase followed by formation of a gel phase at higher concentrations (≥20 mg/mL). As indicated by SAXS, the lamellar phase formed seems to have two d-spacing values (∼5 nm and ∼10 nm (weak), which seems to correspond to two molecules connected tail by tail (5 nm). Further investigation is needed for phase identification, as their properties can affect the physical behavior of BMS-830216 in the development of pharmaceutical dosage forms.

Preparation of smectic itraconazole nanoparticles with tunable periodic order using microfluidics-based anti-solvent precipitation

A microfluidics-based anti-solvent precipitation approach was developed to generate liquid crystalline nanoparticles of itraconazole in a controllable manner. The size, morphology and the structure of nanoparticles were investigated under different precipitation temperatures.

Linking (Pyr)1apelin-13 pharmacokinetics to efficacy: Stabilization and measurement of a high clearance peptide in rodents

Apelin, the endogenous ligand for the APJ receptor, has generated interest due to its beneficial effects on the cardiovascular system. Synthesized as a 77 amino acid preproprotein, apelin is post-translationally cleaved to a series of shorter peptides. Though (Pyr)¹apelin-13 represents the major circulating form in plasma, it is highly susceptible to proteolytic degradation and has an extremely short half-life, making it challenging to quantify. Literature reports of apelin levels in rodents have historically been determined with commercial ELISA kits which suffer from a lack of selectivity, recognizing a range of active and inactive isoforms of apelin peptide. (Pyr)¹apelin-13 has demonstrated beneficial hemodynamic effects in humans, and we wished to evaluate if similar effects could be measured in pre-clinical models. Despite development of a highly selective LC/MS/MS method, in rodent studies where (Pyr)¹apelin-13 was administered exogenously the peptide was not detectable until a detailed stabilization protocol was implemented during blood collection. Further, the inherent high clearance of (Pyr)¹apelin-13 required an extended release delivery system to enable chronic dosing. The ability to deliver sustained doses and stabilize (Pyr)¹apelin-13 in plasma allowed us to demonstrate for the first time the link between systemic concentration of apelin and its pharmacological effects in animal models.

Improving Drug Delivery of Micellar Paclitaxel against Non-Small Cell Lung Cancer by Coloading Itraconazole as a Micelle Stabilizer and a Tumor Vascular Manipulator

Although polymeric micelles of paclitaxel (PTX) significantly reduce excipient-induced toxicity compared with Taxol, they exhibit few clinical advantages in tumor inhibition and overall survival. To improve, itraconazole (ITA), an antifungal drug with potent anti-angiogenesis activity, is co-encapsulated together with PTX within the PEG-PLA micelles. The strong intermolecular interactions between the payloads inhibit drug crystallization and prevent drugs from binding with external proteins, render super-stable micelles upon dilution and exposure to biological environment, and enter the tumor cells through endocytosis. The co-encapsulated micelles show strong anti-proliferation potency against non-small-cell lung cancer (NSCLC) and even PTX resistant NSCLC cells in vitro and significantly improve the drug accumulation within the tumor in vivo. Compared with PTX monotherapy or combination therapy using individual PTX and ITA micelles, the co-encapsulated micelle demonstrates strikingly superior efficacy in tumor growth inhibition, recurrence prevention, and reversion of PTX resistance, in Kras mutant patient derived xenografts, orthotropic models, and paclitaxel-resistance subcutaneous models. Besides the pharmacokinetic improvement, therapeutic benefits are also contributed by angiogenesis inhibition and blood vessel normalization by ITA. Utilizing the pharmaceutical and pharmacological synergies between the therapeutic agents, a simple yet effective design of a combination cancer nanomedicine that is industrially scalable and clinically translatable is achieved.

Liquid Crystals: A Novel Approach for Cancer Detection and Treatment

Liquid crystals are defined as the fourth state of matter forming between solid and liquid states. Earlier the applications of liquid crystals were confined to electronic instruments, but recent research findings suggest multiple applications of liquid crystals in biology and medicine. Here, the purpose of this review article is to discuss the potential biological impacts of liquid crystals in the diagnosis and prognosis of cancer along with the risk assessment. In this review, we also discussed the recent advances of liquid crystals in cancer biomarker detection and treatment in multiple cell line models. Cases reviewed here will demonstrate that cancer diagnostics based on the multidisciplinary technology and intriguingly utilization of liquid crystals may become an alternative to regular cancer detection methodologies. Additionally, we discussed the formidable challenges and problems in applying liquid crystal technologies. Solving these problems will require great effort and the way forward is through the multidisciplinary collaboration of physicists, biologists, chemists, material-scientists, clinicians, and engineers. The triumphant outcome of these liquid crystals and their applications in cancer research would be convenient testing for the detection of cancer and may result in treating the cancer patients non-invasively.

Calcium Chloride Modified Alginate Microparticles Formulated by the Spray Drying Process: A Strategy to Prolong the Release of Freely Soluble Drugs

Alginate (ALG) cross-linking by CaCl₂ is a promising strategy to obtain modified-release drug delivery systems with mucoadhesive properties. However, current technologies to produce CaCl₂ cross-linked alginate microparticles possess major disadvantages, such as a poor encapsulation efficiency of water-soluble drugs and a difficulty in controlling the process. Hence, this study presents a novel method that streamlines microparticle production by spray drying; a rapid, continuous, reproducible, and scalable technique enabling obtainment of a product with low moisture content, high drug loading, and a high production yield. To model a freely water-soluble drug, metformin hydrochloride (MF) was selected. It was observed that MF was successfully encapsulated in alginate microparticles cross-linked by CaCl₂ using a one-step drying process. Modification of ALG provided drug release prolongation-particles obtained from 2% ALG cross-linked by 0.1% CaCl₂ with a prolonged MF rate of dissolution of up to 12 h. Cross-linking of the ALG microparticles structure by CaCl₂ decreased the swelling ratio and improved the mucoadhesive properties which were evaluated using porcine stomach mucosa.

Graphene oxide liquid crystals: a frontier 2D soft material for graphene-based functional materials

Graphene, despite being the best known strong and electrical/thermal conductive material, has found limited success in practical applications, mostly due to difficulties in the formation of desired large-scale highly organized structures. Our discovery of a liquid crystalline phase formation in graphene oxide dispersion has enabled a broad spectrum of highly aligned graphene-based structures, including films, fibers, membranes, and mesoscale structures. In this review, the current understanding of the structure-property relationship of graphene oxide liquid crystals (GOLCs) is overviewed. Various synthetic methods and parameters that can be optimized for GOLC phase formation are highlighted. Along with the results from different characterization methods for the identification of the GOLC phases, the typical characteristics of different types of GOLC phases introduced so far, including nematic, lamellar and chiral phases, are carefully discussed. Finally, various interesting applications of GOLCs are outlined together with the future prospects for their further developments.

Oncogenesis, lipids rafts and liquid crystals: A nanoscopic supplementary field for applied researches and a new hope of advances in cancer

Liquid crystals (LC) are an intermediate state between an ordered crystalline solid and a more disordered liquid. LCs (or mesophases) are ubiquitous in living systems, optimizing multiple biological functions that could not operate in purely solid or liquid environments as both mobility and organization are needed. One of us recently suggested that there is an information vector, shared by neurodegenerative and infectious pathologies, to be found within lipid rafts in an ordered liquid (Lo) form mediated by cholesterol. Here we extend this underlying mechanism to oncogenic processes. The specificity of our approach lies in highlighting the direct involvement of liquid crystals in early carcinogenic processes, by identifying specific metabolic pathways, with the intention of focusing research effort on this level, now that this has become technically feasible. Exploring LCs in living bodies reveals links between numerous oncogenic mechanisms. The approach is based on the geometric properties of amphiphilic (hydrophilic and lipophilic) plasma and intracellular membranes, the phospholipids of which are an example of the lamellar LC phase. These LCs underlie cell signaling and signaling pathways disorders at membrane level: consequently, they are directly concerned with deregulation underlying many cancerous processes. We demonstrate the implication of cancer cell membranes mesophases. That is in the membranes mesophases that are initiated most of metabolic pathways, leading to downstream pathogenic intracellular mechanisms. The concepts of order and of symmetry, in the mathematical sense, involved in condensed matter accompany informed adaptive supramolecular chemical processes in forming self-organizing mesogenic molecular assemblies. Multidisciplinary teamwork combining knowledge from different fields holds out the hope of therapeutic progress upstream of irreversible cancerous processes, while conserving the physiological integrity of the cells themselves.

Liquid Crystal Systems in Drug Delivery

Liquid crystals have been recently studied as novel drug delivery system. The reason behind this is their similarity to colloidal systems in living organisms. They have proven to be advantageous over Traditional, Dermal, Parentral and Oral Dosage forms. Liquid crystals are thermodynamically stable and possess long shelf life. Liquid crystals show bio adhesive properties and sustained release effects. Objective of this book chapter is to provide in-depth information of Pharmaceutical crystal technology. It shall deal with cubic and hexagonal liquid crystal and their applications in Drug delivery system.

p53-independent structure-activity relationships of 3-ring mesogenic compounds' activity as cytotoxic effects against human non-small cell lung cancer lines

BACKGROUND

We recently demonstrated the cytotoxicity of liquid crystal precursors (hereafter referred to as "mesogenic compounds") in the human non-small cell lung cancer (NSCLC) cell line A549 which carry wild-type p53. p53 mutations are observed in 50 % of NSCLC and contribute to their resistance to chemotherapy. To develop more effective and cancer-specific agents, in this study, we investigated the structure-activity relationships of mesogenic compounds with cytotoxic effects against multiple NSCLC cells.

METHODS

The pharmacological effects of mesogenic compounds were examined in human NSCLC cells (A549, LU99, EBC-1, and H1299) and normal WI-38 human fibroblast. Analyses of the cell cycle, cell-death induction, and capsases expression were performed.

RESULTS

The 3-ring compounds possessing terminal alkyl and hydroxyl groups (compounds C1-C5) showed cytotoxicity in NSCLC cells regardless of the p53 status. The compounds C1 and C3, which possess a pyrimidine at the center of the core, induced G2/M arrest, while the compounds without a pyrimidine (C2, C4, and C5) caused G1 arrest; all compounds produced caspase-mediated cell death. These events occurred in a p53-independent manner. Furthermore, it was suggested that compounds induced cell death through p53-independent DNA damage-signaling pathway. Compounds C2, C4, and C5 did not show strong cytotoxicity in WI-38 cells, whereas C1 and C3 did. However, the cytotoxicity of compound C1 against WI-38 cells was improved by modulating the terminal alkyl chain lengths of the compound.

CONCLUSIONS

We showed the p53-indepdent structure-activity relationships of mesogenic compounds related to the cytotoxic effects. These structure-activity relationships will be helpful in the development of more effective and cancer-specific agents.

Crystalline mesophases: Structure, mobility, and pharmaceutical properties

Crystalline mesophases, which are commonly classified according to their translational, orientational, and conformational order as liquid crystals, plastic crystals, and conformationally disordered crystals, represent a common state of condensed matter. As an intermediate state between crystalline and amorphous materials, crystalline mesophases resemble amorphous materials in relation to their molecular mobility, with the glass transition being their common property, and at the same time possessing a certain degree of translational periodicity (with the exception of nematic phase), with corresponding narrow peaks in X-ray diffraction patterns. For example, plastic crystals, which can be formed both by near-spherical molecules and molecules of lower symmetry, such as planar or chain molecules, can have both extremely sharp X-ray diffraction lines and exhibit glass transition. Fundamentals of structural arrangements in mesophases are compared with several types of disorder in crystalline materials, as well as with short-range ordering in amorphous solids. Main features of the molecular mobility in crystalline mesophases are found to be generally similar to amorphous materials, although some important differences do exist, depending on a particular type of mobility modes involved in relaxation processes. In several case studies reviewed, chemical stability appears to follow the extent of disorder, with the stability of crystalline mesophase found to be intermediate between amorphous (least stable) and crystalline (most stable) materials. Finally, detection of crystalline mesophases during manufacturing of two different types of dosage forms is discussed.

Fabrication of novel GMO/Eudragit E100 nanostructures for enhancing oral bioavailability of carvedilol

In the present work, novel nanostructures comprising of glyceryl monooleate (GMO) and Eudragit E100 were prepared using high intensity ultrasonic homogenization. 3(2) Factorial design approach was used for optimization of nanostructures. Results of regression analysis revealed that the amount of GMO and Eudragit E100 had a drastic effect on particle size and percent entrapment efficiency. Optimized carvedilol-loaded nanostructures (Car-NS) were characterized by FTIR, TEM, DSC, in vitro drug release study. Pharmacokinetic parameters such as Cmax, Tmax, Ke, Ka, Vd and AUC were estimated for Car-NS upon its oral administration in Sprague-Dawley rats. Particle size of Car-NS was found to be 183 ± 2.43 nm with an entrapment efficiency of 81.4 ± 0.512%. FTIR studies revealed loading and chemical compatibility of carvedilol with the components of nanostructures. DSC thermograms did not show endothermic peak for melting of carvedilol which could be attributed to solubilization of carvedilol in molten GMO during DSC run. The prepared Car-NS released carvedilol in sustained manner over a period of 10 h as suggested by in vitro drug release study. The pharmacokinetic study of Car-NS showed significant improvement in Cmax (two fold, p < 0.001) and AUC (four folds, p < 0.001) of carvedilol when compared to carvedilol suspension. Car-NS were found to be stable for a period of 3 months. Thus, a stable, floating, multiparticulate GMO/Eudragit E100 nanostructures having ability to release the drug in sustained manner with enhanced oral bioavailability can prove to be a promising carrier system for poorly water soluble drugs.

Peptide KSL-W-Loaded Mucoadhesive Liquid Crystalline Vehicle as an Alternative Treatment for Multispecies Oral Biofilm

Decapeptide KSL-W shows antibacterial activities and can be used in the oral cavity, however, it is easily degraded in aqueous solution and eliminated. Therefore, we aimed to develop liquid crystalline systems (F1 and F2) for KSL-W buccal administration to treat multispecies oral biofilms. The systems were prepared with oleic acid, polyoxypropylene (5) polyoxyethylene (20) cetyl alcohol (PPG-5-CETETH-20), and a 1% poloxamer 407 dispersion as the oil phase (OP), surfactant (S), and aqueous phase (AP), respectively. We characterized them using polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), rheology, and in vitro bioadhesion, and performed in vitro biological analysis. PLM showed isotropy (F1) or anisotropy with lamellar mesophases (F2), confirmed by peak ratio quantification using SAXS. Rheological tests demonstrated that F1 exhibited Newtonian behavior but not F2, which showed a structured AP concentration-dependent system. Bioadhesion studies revealed an AP concentration-dependent increase in the system’s bioadhesiveness (F2 = 15.50 ± 1.00 mN·s) to bovine teeth blocks. Antimicrobial testing revealed 100% inhibition of multispecies oral biofilm growth after KSL-W administration, which was incorporated in the F2 aqueous phase at a concentration of 1 mg/mL. Our results suggest that this system could serve as a potential vehicle for buccal administration of antibiofilm peptides.

Exploring the Phase Behavior of Monoolein/Oleic Acid/Water Systems for Enhanced Donezepil Administration for Alzheimer Disease Treatment

Donepezil is a drug usually administered by oral route for Alzheimer disease treatment, but several gastric side effects have been reported as diarrhea, nausea, and anorexia. We explored the phase behavior of lyotropic liquid crystalline (LLC) mesophases composed by monoolein/oleic acid/water for enhanced administration of donepezil. Polarized light microscopy suggested that these systems ranged from isotropic inverse micellar solutions (L2) to viscous and birefringent reverse hexagonal (HII) mesophases according to the amount of water in the ternary systems. Phase transition was observed from a L2 phase to HII mesophase after swelling studies, an interesting property to be explored as a precursor of LLC mesophases for mucosal administration that increases its viscosity in situ. Mucoadhesive properties of LLC mesophases were characterized using a texture analyzer indicating that these systems can have an increased residence time in the site of absorption. Donepezil-free base was incorporated in the evaluated formulations, and their in vitro release was controlled up to 24 h. The phase behavior of the systems demonstrated a great potential for enhanced donepezil administration once these mucoadhesive-controlled release formulations can incorporate the drug and prolong its release, possibly reducing its side effects.

The solid-state continuum: a perspective on the interrelationships between different solid-state forms in drug substance and drug product

Objective

The objective of the review is to provide an overview of the nomenclature used in the solid-state continuum and relate these to the development of drug substances and drug products.

Key findings

The importance of a rational approach to solid-state form selection, including integrated decision making (ensuring equal weight is given to the needs of the drug substance and the drug product), is vital for the effective development of a drug candidate. For example, how do secondary processing considerations influence the selection of drug substance solid-state form and resulting formulation, and how can drug substance solid-state form be used to optimise secondary processing? Further, the potential use of ‘crystal’ engineering to optimise stability, purity and optical resolutions, and the linked regulatory requirements, will be discussed.

Summary

The nomenclature used in the solid-state continuum, which contains a large number of different crystalline and non-crystalline forms, for example, amorphous systems, was reviewed. Further, the significant role of the drug substance within the solid oral dose form from a physicochemical perspective was covered.

A liquid crystal-related compound induces cell cycle arrest at the G2/M phase and apoptosis in the A549 human non-small cell lung cancer cell line

Liquid crystals are the state of matter existing between liquid and crystalline phases, and recently there has been increasing interest in their biological effects. Following our recently reported work, we investigated the cell suppressive effects of liquid crystal-related compounds (LCRCs), which are precursors of liquid crystals, in the human non-small lung cancer cell line A549. We found that 2-(4-butoxyphenyl)-5-(4-hydroxyphenyl)pyrimidine (LCRC-1) dramatically suppressed cell growth. Treatment with 12 µM LCRC-1 for 12 h induced cell cycle arrest at the G2/M phase. Furthermore, LCRC-1 increased the sub-G1 fraction and Annexin V-positive cells and activated caspase-3 in A549 cells, which showed that it can induce apoptosis in these cells. Furthermore, because the induction of apoptosis by LCRC-1 was partly inhibited by treatment with pan-caspase inhibitor, it appeared that LCRC-1 induced apoptosis by a caspase-dependent pathway. The ability of LCRC-1 to cause DNA damage was assessed, but LCRC-1 did not induce expression of γ-H2AX, which is a marker of DNA damage. Treatment with LCRC-1 did not inhibit the proliferation of WI-38 normal fibroblast cells, which makes the tumor-specific suppressive effect of LCRC-1 attractive for its application as a new antitumor drug.

Liquid crystal-related compound-induced cell growth suppression and apoptosis in the chronic myelogenous leukemia K562 cell line

Liquid crystals are the state of matter existing between the liquid and the crystalline phase, and there is a recent surging interest in its biological effects. Our previous study showed that liquid crystal-related compounds (LCRCs), which are precursors of the liquid crystal, enhanced hematopoietic differentiation at a relatively low concentration (Biol Pharm Bull, 32, 2009). However, biological potentials of LCRCs on tumor cells are unclear. In this study, the biological activity of 16 LCRCs to a chronic myelogenous leukemia cell line, K562, was evaluated. As a result, two compounds, 2-(4-butoxyphenyl)-5-(4-hydroxyphenyl)pyrimidine (compound 7) and 2-{4-(4-hexyloxyphenyl)phenyl}-5-hydroxypyrimidine (compound 9) showed marked growth suppression of K562 cells at μM range. These compounds are similar in structure with a core of three aromatic rings including a pyrimidine ring and residues of one alkyl chain and one hydroxide on either side. In addition, only compound 7 induced the activation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase, and apoptosis of K562 cells. The contrasting results between compounds 7 and 9 indicate different mechanisms to suppress the cell proliferation between the two compounds. These results suggest the possibility of LCRCs for application as new antitumor drugs.