SMGA gels for the skin permeation of haloperidol

Prediction of drug permeation through microneedled skin by machine learning

Stratum corneum is the outermost layer of the skin preventing external substances from entering human body. Microneedles (MNs) are sharp protrusions of a few hundred microns in length, which can penetrate the stratum corneum to facilitate drug permeation through skin. To determine the amount of drug delivered through skin, in vitro drug permeation testing is commonly used, but the testing is costly and time-consuming. To address this issue, machine learning methods were employed to predict drug permeation through the skin, circumventing the need of conducting skin permeation experiments. By comparing the experimental data and simulated results, it was found extreme gradient boosting (XGBoost) was the best among the four simulation methods. It was also found that drug loading, permeation time, and MN surface area were critical parameters in the models. In conclusion, machine learning is useful to predict drug permeation profiles for MN-facilitated transdermal drug delivery.

Organogel of Acai Oil in Cosmetics: Microstructure, Stability, Rheology and Mechanical Properties

Organogel (OG) is a semi-solid material composed of gelling molecules organized in the presence of an appropriate organic solvent, through physical or chemical interactions, in a continuous net. This investigation aimed at preparing and characterizing an organogel from acai oil with hyaluronic acid (HA) structured by 12-hydroxystearic acid (12-HSA), aiming at topical anti-aging application. Organogels containing or not containing HA were analyzed by Fourier-transform Infrared Spectroscopy, polarized light optical microscopy, thermal analysis, texture analysis, rheology, HA quantification and oxidative stability. The organogel containing hyaluronic acid (OG + HA) has a spherulitic texture morphology with a net-like structure and absorption bands that evidenced the presence of HA in the three-dimensional net of organogel. The thermal analysis confirmed the gelation and the insertion of HA, as well as a good thermal stability, which is also confirmed by the study of oxidative stability carried out under different temperature conditions for 90 days. The texture and rheology studies indicated a viscoelastic behavior. HA quantification shows the efficiency of the HA cross-linking process in the three-dimensional net of organogel with 11.22 µg/mL for cross-linked HA. Thus, it is concluded that OG + HA shows potentially promising physicochemical characteristics for the development of a cosmetic system.

Recent advances on small molecular gels: formation mechanism and their application in pharmaceutical fields

INTRODUCTION

As an essential complement to chemically cross-linked macromolecular gels, drug delivery systems based on small molecular gels formed under the driving forces of non-covalent interactions are attracting considerable research interest due to their potential advantages of high structural functionality, lower biological toxicity, reversible stimulus-response, and so on.

AREA COVERED

The present review summarizes recent advances in small molecular gels and provides their updates as a comprehensive overview in terms of gelation mechanism, gel properties, and physicochemical characterizations. In particular, this manuscript reviews the effects of drug-based small molecular gels on the drug development and their potential applications in the pharmaceutical fields.

EXPERT OPINION

Small molecular-based gel systems, constructed by inactive compounds or active pharmaceutical ingredients, have been extensively studied as carriers for drug delivery in pharmaceutical field, such as oral formulations, injectable formulations, and transdermal formulations. However, the construction of such gel systems yet faces several challenges such as rational and efficient design of functional gelators and the great occasionality of drug-based gel formation. Thus, a deeper understanding of the gelation mechanism and its relationship with gel properties will be conducive to the construction of small molecular gels systems and their future application.

Enhanced skin retention and permeation of a novel peptide via structural modification, chemical enhancement, and microneedles

Hyperpigmentation is a common skin condition with serious psychosocial consequences. Decapeptide-12, a novel peptide, has been found to be safer than hydroquinone in reducing melanin content, with efficacy up to more than 50% upon 16 weeks of twice-daily treatment. However, the peptide suffers from limited transcutaneous penetration due to its hydrophilicity and high molecular weight. Therefore, decapeptide-12 was modified by adding a palmitate chain in an attempt to overcome this limitation. Molecular docking results showed that the two peptides exhibited similar biological activity towards tyrosinase. We also tested the effect of chemical penetration enhancers and microneedles to deliver the two peptides into and through skin, using an in vitro human skin permeation method. It was shown that the palm-peptide achieved the best skin retention owing to the increased lipophilicity. In addition, skin permeation of the palm-peptides was enhanced by the chemical skin penetration enhancers, namely, oleic acid and menthol. Skin permeation of the native peptide was enhanced by the microneedle patch but not the chemical skin penetration enhancers. Cutaneous absorption of the palm-peptides was estimated to have achieved its therapeutic concentration within skin. The combinatory approach of using molecular modification, chemical penetration enhancement, and microneedle patch proves to be useful to enhanceskin permeation of the peptides.

ABH Gel: Comforting Cure or Pricey Placebo?

Despite a lack of evidence of benefit, the compounded product ABH gel (lorazepam, diphenhydramine, and haloperidol) continues to be prescribed for individuals in hospice and palliative care settings for the treatment of nausea and vomiting and terminal delirium. More effective and reliable pharmacological and nonpharmacological strategies exist for the treatment of these conditions in the palliative care and hospice settings. We discuss the pharmacokinetic and clinical evidence for the individual components of ABH gel, as well as the compounded product, and attempt to understand the mechanism of effect that some purport to see, as well as why the compound continues to enjoy such a cult following. Truly, the continued use of ABH gel makes for a pricey placebo and delays the treatment of end-of-life symptoms with modalities that work.

Esters of terpene alcohols as highly potent, reversible, and low toxic skin penetration enhancers

Skin penetration/permeation enhancers are compounds that improve (trans)dermal drug delivery. We designed hybrid terpene-amino acid enhancers by conjugating natural terpenes (citronellol, geraniol, nerol, farnesol, linalool, perillyl alcohol, menthol, borneol, carveol) or cinnamyl alcohol with 6-(dimethylamino)hexanoic acid through a biodegradable ester linker. The compounds were screened for their ability to increase the delivery of theophylline and hydrocortisone through and into human skin ex vivo. The citronellyl, bornyl and cinnamyl esters showed exceptional permeation-enhancing properties (enhancement ratios up to 82) while having low cellular toxicities. The barrier function of enhancer-treated skin (assessed by transepidermal water loss and electrical impedance) recovered within 24 h. Infrared spectroscopy suggested that these esters fluidized the stratum corneum lipids. Furthermore, the citronellyl ester increased the epidermal concentration of topically applied cidofovir, which is a potent antiviral and anticancer drug, by 15-fold. In conclusion, citronellyl 6-(dimethylamino)hexanoate is an outstanding enhancer with an advantageous combination of properties, which may improve the delivery of drugs that have a limited ability to cross biological barriers.

Enhancement of Transdermal Delivery of Haloperidol via Spanlastic Dispersions: Entrapment Efficiency vs. Particle Size

Haloperidol (Hal) is a well-known typical antipsychotic. Hepatic first pass metabolism leads to its limited oral bioavailability. This study aimed at enhancing transdermal delivery of Hal via spanlastic formulae. Hal-loaded spanlastics of Span®60 and an edge activator (EA) were successfully prepared by ethanol injection method according to a 3¹.4¹ full factorial design. In this design, independent variables were X₁, EA type, and X₂, Span®60 to EA ratio. Y₁, percentage entrapment efficiency (EE%); Y₂, particle size (PS); Y₃, deformability index (DI); and Y₄, percentage drug released after 4h (Q4h), were chosen as dependent variables. The Fourier-transform infrared spectral analysis showed no considerable chemical interaction between Hal and the used excipients. Both factors affected significantly all the responses except DI. Desirability of each prepared formula was calculated based on maximizing EE% and Q4h and minimizing PS. Formula F6, with X₁, Tween®80, and X₂, 8:2, had the highest desirability value followed by F7, with X₁, Tween®80, and X₂, 6:4, and both were chosen as selected formulae (SF) for further investigation. F6 (having more entrapped Hal), F7 (of smaller PS), and Hal solution in propylene glycol were subjected to ex vivo permeation test through newborn rat skin. Both formulae showed marked enhancement in drug permeation compared with drug solution. The significantly higher Q_36h and J_36h of F7 from F6 may indicate that the smaller particle size aided more than higher entrapment in achieving a higher permeation for Hal of 3.5±0.2μg/cm².h. These results are promising for further investigation of this formula.

Penetration enhancer-containing spanlastics (PECSs) for transdermal delivery of haloperidol: in vitro characterization, ex vivo permeation and in vivo biodistribution studies

Haloperidol (Hal) is one of the widely used antipsychotic drugs. When orally administered, it suffers from low bioavailability due to hepatic first pass metabolism. This study aimed at developing Hal-loaded penetration enhancer-containing spanlastics (PECSs) to increase transdermal permeation of Hal with sustained release. PECSs were successfully prepared using ethanol injection method showing reasonable values of percentage entrapment efficiency, particle size, polydispersity index and zeta potential. The statistical analysis of the ex vivo permeation parameters led to the choice of F1L – made of Span^® 60 and Tween^® 80 at the weight ratio of 4:1 along with 1% w/v Labrasol^® – as the selected formula (SF). SF was formulated into a hydrogel by using 2.5% w/v of HPMC K4M. The hydrogel exhibited good in vitro characteristics. Also, it retained its physical and chemical stability for one month in the refrigerator. The radiolabeling of SF showed a maximum yield by mixing of 100 µl of diluted formula with 50 µl saline having 200 MBq of ^99mTc and containing 13.6 mg of reducing agent (NaBH₄) and volume completed to 300 µl by saline at pH 10 for 10 min as reaction time. The biodistribution study showed that the transdermal ^99mTc-SF hydrogel exhibited a more sustained release pattern and longer circulation duration with pulsatile behavior in the blood and higher brain levels than the oral ^99mTc-SF dispersion. So, transdermal hydrogel of SF may be considered a promising sustained release formula for Hal maintenance therapy with reduced dose size and less frequent administration than oral formula.

β-Cyclodextrin-based ternary complexes of haloperidol and organic acids: the effect of organic acids on the drug solubility enhancement

Haloperidol (HALO) is a weak base with very low aqueous solubility that is used as an antipsychotic drug. This study aimed to improve its solubility by forming HALO/β-cyclodextrin (β-CD)-based ternary complexes with organic acids. The solubility of HALO/β-CD binary and HALO/β-CD/organic acid ternary complexes in different media (i.e. citrate buffer pH 3 and 6) was explored. The stoichiometric ratio between the drug and β-CD was 1:1 in all complexes formed. The solubility of HALO/β-CD binary complexes significantly increased in citrate buffer pH 3 compared with citrate buffer pH 6. For the ternary complexes, HALO/β-CD/tartaric acid and HALO/β-CD/lactic acid in citrate buffer pH 3 increased HALO solubility compared with HALO/β-CD/succinic acid due to their higher unionized species. The highest stability constant and complexation efficiency values in citrate buffer pH 3 were shown by the ternary complexes with lactic acid followed by tartaric acid and succinic acid, respectively. Results indicated that lactic acid provided the greatest binding strength and solubilization efficiency for the complex.

Multi-stimuli-responsive chiral organogels based on peptide derivatives

A series of chiral aryl amide compounds bearing peptide pendants have been investigated as low molecular weight gelators. A mechanistic study reveals that complementary hydrogen bonding from peptide pendants is the main driving force for the formation of organogels. This new class of organogels can exhibit multi-stimuli-responsive behavior upon applying (1) thermal, (2) pH, (3) enantiomeric purity, and (4) fluoride anion stimuli. Enantiomeric purity as a new external stimulus displays sensitive stimuli-responsiveness; only 0.02 equiv. of the enantiomer can completely disassemble the gel aggregate. They will serve as excellent smart materials with potential applications in chiral sensors, recognition, and separation.

Distinct kinetics of molecular gelation in a confined space and its relation to the structure and property of thin gel films

Distinct kinetic feature of the molecular gelation in a confined or unconfined regime, and its relationship with the tailored fiber network structure and mechanical properties.

Correlation between hierarchical structure of crystal networks and macroscopic performance of mesoscopic soft materials and engineering principles

The performance of soft materials is correlated with the hierarchical crystal network structure by topology, correlation length, symmetry/ordering, and strength.

Drug permeation through skin is inversely correlated with carrier gel rigidity

Controlled release plays an essential role in formulating topical and transdermal drug delivery systems. In this study, we correlated the skin permeation of Sesamin, a lipophilic drug, with the rheological properties of two different organogel carriers, i.e., low molecular weight gelling agent N-lauroyl-l-glutamic acid di-n-butylamide (GP-1) and Carbopol polymeric gels. Although these two gels have distinct network structures, they share the same trend: the more rigid the gel network and the higher the gelator concentration, the lower the steady flux of Sesamin through skin. This negative correlation lies in the fact that organogel network hinders the diffusion of drug to the gel-skin interface; as a result, the depletion zone near the interface is non-negligible and contributes to the resistance of the whole diffusion system, and thus, the permeation flux is reduced. More interestingly, the dependence of the steady flux against gel complex modulus at the linear viscoelastic region followed a "universal" power law regardless of the gel types, i.e., 1/J = 1/J0 + a(G*)(ε)/C0 with a = 11.25, ε = 0.21 ± 0.03 for GP-1 gels, and a = 0.16, ε = 1.05 ± 0.06 for Carbopol gels, J0 is the steady flux without gel (G* = 0), and C0 is the initial concentration of drug in gels. The empirical formulae are crucial in developing transdermal organogel systems with controlled release of drug content through readily obtainable data of their rheological properties. The explanation for the power law dependence of the steady flux on gel complex modulus is discussed.

N-Myristoylglutamic Acid Derivative of 3'-Fluoro-3'-Deoxythymidine as an Organogel

Designing microbicidal gels of anti-HIV drugs for local application to prevent HIV infection is a subject of major interest. 3'-Fluoro-3'-deoxythymidine (FLT), a nucleoside reverse transcriptase inhibitor (NRTI), was conjugated with a N-myristoyl glutamate scaffold. The conjugate showed gelation at 1% (w/w) in different organic solvents, such as toluene, dichloromethane, and chloroform. The gels were opaque and stable at room temperature. The results indicate that myristoyl glutamate derivative of FLT can form an organogel. The gel could have potential application as a topical anti-HIV microbicidal agent.

Nanosized ethosomes bearing ketoprofen for improved transdermal delivery

The potential of ethosomes for delivering ketoprofen via skin was evaluated. The ethosomes were prepared, optimized and characterized. Vesicular shape, size and entrapment efficiency were determined by transmission electron microscopy, dynamic light scattering and minicolumn centrifugation technique, respectively. Vesicle sizes varied from 120.3±6.1 to 410.2±21.8 nm depending on the concentrations of soya phosphatidyl choline (SPC) and ethanol. Entrapment efficiency increased with concentrations of SPC and ethanol. The formulations exhibited entrapment efficiencies of 42-78%. In vitro release through cellophane membrane showed sustained release of drug from ethosomal formulations in contrast to hydroalcoholic drug solution (HA), which released most of the drug within 2-3 h. In vitro drug permeation across human skin revealed improved drug permeation and higher transdermal flux with ethosomal formulations compared to hydroethanolic drug solution. Kinetics of in vitro skin permeation showed zero order drug release from formulations. Based on in vitro transdermal flux, the estimated steady state in vivo plasma concentration from ethosomes attained therapeutic drug levels whereas hydroalcoholic drug solution exhibited sub therapeutic drug concentration with a patch size of 50 cm(2). Skin permeation of ethosomal formulations assessed by confocal microscopy revealed enhanced permeation of Rhodamine 123 loaded formulation in comparison to the hydroalcoholic solution.

Effects of K openers on the QT prolongation induced by HERG-blocking drugs in guinea-pigs

OBJECTIVES

This work evaluated the potential usefulness of pharmacological activation of cardiac ATP-sensitive potassium channels (K(ATP)) in the prevention of drug-induced QT prolongation in anaesthetised guinea-pigs. Prolongation of cardiac repolarisation and QT interval is an adverse effect of many drugs blocking HERG potassium channels. This alteration can be dangerously arrhythmogenic and has been associated with the development of a particular form of ventricular tachyarrhythmia known as torsade de pointes.

METHODS

The well-known K(ATP) openers aprikalim, cromakalim and pinacidil were used. Moreover, three benzothiazine derivatives, which have been reported as potent activators of K(ATP) channels, were also used.

KEY FINDINGS

Pharmacological activation of K(ATP) channels caused a reduction of the QT prolongation, induced by astemizole, cisapride, quinidine and thioridazine. In contrast, the QT prolongation induced by haloperidol, sotalol and terfenadine, which are known to block HERG channels but also K(ATP) channels, was not influenced by K(ATP) activation. Glibenclamide and tolbutamide (non-selective blockers of K(ATP) channels expressed both in sarcolemmal and in mitochondrial membranes) antagonised the effects of K(ATP) openers, whereas 5-hydroxydecanoic acid (selective blocker of the mitochondrial K(ATP) channels) failed to antagonise the effects of K(ATP) openers, indicating that only the sarcolemmal K(ATP) is involved in the cardioprotective activity.

CONCLUSIONS

The data suggest that pharmacological K(ATP) activation might represent an option for treatment of patients exposed to QT-prolonging drugs.

Fabrication of nanotubules and microspheres from the self-assembly of amphiphilic monochain stearic acid derivatives

A series of amphiphilic monochain derivatives of stearic acid, CH(3)(CH(2))(16)CONH(CH(2))(n)NH(2) (n = 2, 3, 4, 6), CH(3)(CH(2))(16)CONH(CH(2))(2)S(2)(CH(2))(2)NH(2), and [CH(3)(CH(2))(16)CONH](2)(CH(2))(2), are synthesized, and their self-assembly behaviors have been investigated in 1,2-dichloroethane (DCE). In addition to the concentration of the compound in DCE, the number of methylene units in hydrophilic segments play a crucial role in determining the final morphology of self-assembling structures from nanotubules with 20 nm inner diameter to microspheres with an average diameter of 20 μm. The external texture of the microsphere is also influenced by the number of methylene units in the hydrophilic segment. The microspheres formed by highly ordered aggregation of nanobelts show high thermal stability. The particular processes and causations have been expatiated.

Glucose-based fluorescent low-molecular mass compounds: creation of simple and versatile supramolecular gelators

Five novel glucose-based naphthalene derivatives with linkers containing hydrazine, ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, and 1,6-hexanediamine, respectively (1, 2, 3, 4, and 5) were designed and prepared. The gelation test revealed the following points: (1) within the 30 solvents tested, 1 gels water only; (2) in contrast, 2 gels not only water, but also 11 of the organic solvents tested, a typical "ambidextrous gelator"; (3) 3, 4, and 5, however, gel organic solvents only, and the numbers of solvents gelled are 11, 11 and 13, respectively. Clearly, these compounds are effective low-molecular mass gelators, and show transitions from a low-molecular mass hydrogelator to an ambidextrous gelator and then to low-molecular mass organogelators with a slight increase in the length of the spacers. Interestingly, 5 is a super gelator to acetonitrile, of which the minimum gelation concentration is only 0.07%, w/v. The morphology, microstructure and molecular aggregation of the system strongly depend on the transition, as revealed by SEM, contact angle, energy dispersive X-ray spectroscopy, and XRD measurements. More interestingly, an aggregation-induced enhanced emission was observed along with gelation. Furthermore, the system appeared as a supramolecular chiroptical switch in the sol-gel process that is the chirality disappeared when the gel was heated to solution, whereas it reappeared when cooled to a gel.

Spherulitic networks: from structure to rheological property

A finite element method based on ABAQUS is employed to examine the correlation between the microstructure and the elastic response of planar Cayley treelike fiber networks. It is found that the elastic modulus of the fiber network decreases drastically with the fiber length, following the power law. The power law of elastic modulus G' vs the correlation length xi obtained from this simulation has an exponent of -1.71, which is close to the exponent of -1.5 for a single-domain network of agar gels. On the other hand, the experimental results from multidomain networks give rise to a power law index of -0.49. The difference between -1.5 and -0.49 can be attributed to the multidomain structure, which weakens the structure of the overall system and therefore suppresses the increase in G'. In addition, when the aspect ratio of the fiber is smaller than 20, the radius of the fiber cross-section has a great impact on the network elasticity, while, when the aspect ratio is larger than 20, it has almost no effect on the elastic property of the network. The stress distribution in the network is uniform due to the symmetrical network structure. This study provides a general understanding of the correlation between microscopic structure and the macroscopic properties of soft functional materials.

Confinement effects on the self-assembly of 1,3:2,4-Di-p-methylbenzylidene sorbitol based organogel

1,3:2,4-di- p-methylbenzylidene sorbitol (MDBS) is a small organic molecule that is capable of inducing self-assembly in a wide variety of organic solvents and of forming organogels. In this paper, we present a novel approach to tune the network architectures of organogels by utilizing geometric confinement while varying the gelator concentration. Self-assembly of MDBS in propylene carbonate (PC) is investigated in a series of microchannels with widths varying from 20 to 80 mum and the gelator concentration varying from 2 to 7 wt %. We demonstrate by optical microscopy and scanning electron microscopy (SEM) that a transition from fibrillar structure to sheaflike spherulite structure occurs when (a) the channel width is increased for fixed gelator concentrations and (b) gelator concentration is increased for fixed channel widths. A phase diagram is built based on these observations. Polarized microscopy and transmission electron microscopy (TEM) images are also obtained for organogel under unconfined condition to display the spherulite structures viewed under different length scales. The thermal properties of the organogel are measured by differential scanning calorimetry (DSC) to verify the structural difference obtained under confined and unconfined conditions and the structure stability. Our results provide a novel strategy to control the topological structure of self-assembled systems and to modify their thermal properties via geometric confinement.

New dicholesteryl-based gelators: chirality and spacer length effect

Eight new diacid amides of dicholesteryl L(D)-alaninates were designed and prepared. The compounds with spacers containing three, four, five, or six carbon atoms and L-alanine residues are denoted as 1a, 2a, 3a, and 4a, respectively, and those containing D-alanine residues are denoted as 1b, 2b, 3b, and 4b, respectively. A gelation test revealed that a subtle change in the length of the spacer and an inverse in the chirality of the amino acid residue can produce a dramatic change in the gelation behavior of the compounds and the microstructures of the gels, as revealed by SEM, XRD, and CD measurements. Importantly, for the compounds 1 and 2, those containing d-alanine residues (1b, 2b) are more efficient gelators than their analogues with opposite chirality (1a, 2a). For the compounds of longer spacers (3, 4), however, those containing l-alanine residues (3a, 4a) are superior to the corresponding ones with d-alanine residues (3b, 4b). Very interestingly, of the 139 gel systems studied, at least 11 of them gel spontaneously at room temperature. Studies of the rheological properties of the example systems of these gels demonstrated that change in the spacer lengths of the gelators has a great effect upon the mechanical properties of the corresponding gels, and the studies also revealed the thixotropic properties of the gels. Furthermore, it was observed that 4a forms water-in-oil gel emulsions with some organic solvents by simple agitating the systems at room temperature.

Organogels and their use in drug delivery--a review

Organogels are semi-solid systems, in which an organic liquid phase is immobilized by a three-dimensional network composed of self-assembled, intertwined gelator fibers. Despite their majoritarily liquid composition, these systems demonstrate the appearance and rheological behaviour of solids. Investigative research pertaining to these systems has only picked up speed in the last few decades. Consequently, many burning questions regarding organogel systems, such as the specific molecular requirements guaranteeing gelation, still await definite answers. Nonetheless, the application of different organogel systems to various areas of interest has been quick to follow their discoveries. Unfortunately, their use in drug delivery is still quite limited by the scarce toxicology information available on organogelators, as well as by the few pharmaceutically-accepted solvents used in gel systems. This review aims at providing a global view of organogels, with special emphasis on the interplay between the gelator's structural characteristics and the ensuing intermolecular interactions. A subsequent focus is placed on the application of organogels as drug delivery platforms for active agent administration via diverse routes such as transdermal, oral, and parenteral.

Formulation development of transdermal dosage forms: Quantitative structure-activity relationship model for predicting activities of terpenes that enhance drug penetration through human skin

Terpenes and terpenoids have been used as enhancers in transdermal formulations for facilitating penetration of drugs into human skin. Knowledge of the correlation between the human skin penetration effect (HSPE) and the physicochemical properties of these enhancers is important for facilitating the discovery and development of more enhancers. In this work, the HSPE of 49 terpenes and terpenoids were compared by the in vitro permeability coefficients of haloperidol (HP) through excised human skin. A first-order multiple linear regression (MLR) model was constructed to link the permeability coefficient of the drug to the lipophilicity, molecular weight, boiling point, the terpene type and the functional group of each enhancer. The Quantitative Structure-Activity Relationship (QSAR) model was derived from our data generated by using standardized experimental protocols, which include: HP in propylene glycol (PG) of 3 mg/ml as the donor solution containing 5% (w/v) of the respective terpene, the same composition and volume of receptor solution, similar human skin samples, in the same set of automated flow-through diffusion cells. The model provided a simple method to predict the enhancing effects of terpenes for drugs with physicochemical properties similar to HP. Our study suggested that an ideal terpene enhancer should possess at least one or combinations of the following properties: hydrophobic, in liquid form at room temperature, with an ester or aldehyde but not acid functional group, and is neither a triterpene nor tetraterpene. Possible mechanisms revealed by the QSAR model were discussed.

Architecture of a Biocompatible Supramolecular Material by Supersaturation-Driven Fabrication of its Fiber Network

The architecture of a biocompatible organogel formed by gelation of a small molecule organic gelator, N-lauroyl-L-glutamic acid di-n-butylamide, in isostearyl alcohol was investigated based on a supersaturation-driven crystallographic mismatch branching mechanism. By controlling the supersaturation of the system, the correlation length that determines the mesh size of the fiber network was finely tuned and the rheological properties of the gel were engineered. This approach is of considerable significance for many gel-based applications, such as controlled release of drugs that requires precise control of the mesh size. A direct cryo-transmission electron microscopy (TEM) imaging technique capable of preserving the network structure was used to visualize its nanostructure.