Investigation of the Absorption of Nanosized lamotrigine Containing Nasal Powder via the Nasal Cavity.

Nasal drug delivery has become a popular research field in the last years. This is not surprising since the nose possesses unique anatomical and physical properties. Via the nasal mucosa local, systemic, and directly central nerve systemic (CNS) effect is achievable. Powders have favorable physicochemical properties over liquid formulations. Lamotrigine (LAM) is an antiepileptic agent with a relatively mild side effect spectrum, but only available in tablet form on market. Reducing the particle size to the nano range can affect the bioavailability of pharmaceutical products. The aim of this article was to continue the work started, compare the in vitro properties of a nanonized lamotrigine containing nasal powder (nanoLAMpowder) and its physical mixture (PM) that were prepared by dry milling. Moreover, to study their trans-epithelial absorption to reach the blood and target the brain by axonal transport. Due to the dry milling technique, the particle size of LAM, their surface and also their structure changed that led to higher in vitro dissolution and permeability rate. The results of the in vivo tests showed that the axonal transport of the drug was assumable by both intranasal formulations because the drug was present in the brain within a really short time, but the LAM from the nanoLAMpowder liberated even faster.

Investigation of Absorption Routes of Meloxicam and Its Salt Form from Intranasal Delivery Systems.

The aim of this article was to study the trans-epithelial absorption to reach the blood and to target the brain by axonal transport using nasal formulations with nanonized meloxicam (nano MEL spray) and its salt form known as meloxicam potassium monohydrate (MELP spray). The physicochemical properties and the mucoadhesivity of nasal formulations were controlled. In vitro and in vivo studies were carried out. These forms were first investigated in "nose-to-brain" relation. It was found that the in vitro study and in vivo study did not show any significant correlation. In vitro experiments demonstrated faster dissolution rate and higher diffusion of MELP from the spray compared with the nano MEL spray. The administration of the nano MEL spray resulted in faster absorption and constant plasma concentration of the drug after five minutes of administration as compared to MELP. The axonal transport of the drug was justified. MEL appeared in the brain tissues after the first five minutes of administration in the case of both spray forms, but its amount was too small in comparison with the total plasma concentration. The application of the nano MEL spray resulted in the same AUC in the brain as the intravenous injection. The "nose-to-blood" results predicted the nasal applicability of MEL and MELP in pain management. The "nose-to-brain" pathway requires further study.

Allosteric activation of metabotropic glutamate receptor 5.

Metabotropic glutamate receptor 5 (mGluR5) is a class C G protein-coupled receptor (GPCR) with both an extracellular ligand binding site and an allosteric intrahelical chamber located similarly to the orthosteric ligand binding site of Class A GPCRs. Ligands binding to this ancestral site of mGluR5 can act as positive (PAM), negative (NAM) or silent (SAM) allosteric modulators, and their medicinal chemistry optimization is notoriously difficult, as subtle structural changes may cause significant variation in activity and switch in the functional response. Here we present all atom molecular dynamics simulations of NAM, SAM and PAM complexes formed by closely related ligands and analyse the structural differences of the complexes. Several residues involved in the activation are identified and the formation of a continuous water channel in the active complex but not in the inactive ones is recognized. Our results suggest that the mechanism of mGluR5 activation is similar to that of class A GPCRs.Communicated by Ramaswamy H. Sarma.

Preparation and investigation of core-shell nanoparticles containing human interferon-α.

Sustained release of active interferon-α (IFN-α) has been achieved from core-shell nanoparticles (NPs) prepared by aqueous precipitation of IFN-α-enriched human serum albumin (HSA-IFN-α) and layer-by-layer (L-b-L) by coating of the IFN-α NPs with poly(sodium-4-styrene) sulphonate (PSS) and chitosan (Chit). The concentration and the pH of HSA solution were optimized during the development of this method. Dynamic light scattering (DLS), zeta-potential, thermal analysis (differential scanning calorimetry (DSC) and termogravimetry (TG)), X-ray diffraction (XRD), IFN-α activity and morphology (transmission electron microscope (TEM)) studies were used to control the preparation and analyse the products. The dissolution kinetics of NPs was measured in vitro over 7 days in Hanson dissolution tester with Millex membrane. In vivo studies in Pannon white rabbit detected steady IFN-α plasma level for 10 days after subcutaneous injection administration of the HSA-IFN-α NPs. The IFN-α plasma concentration was detected by using the enzyme-linked immunosorbent assay (ELISA) method. In the present paper we discuss the preparation method, the optimization steps and the results of in vitro and in vivo release studies. It was established that 76.13% HSA-IFN-α are encapsulated in the core-shell NPs.

Nasal delivery of nanosuspension-based mucoadhesive formulation with improved bioavailability of loratadine: Preparation, characterization, and in vivo evaluation.

The unique requirements of poorly water-soluble drug delivery have driven a great deal of research into new formulations and routes of administration. This study investigates the use of nanosuspensions for solubility enhancement and drug delivery. Simple methods were used to prepare nasal formulations of loratadine based on nanosuspension pre-dispersion with sodium hyaluronate as a mucoadhesive agent. The nanosuspension was prepared by antisolvent precipitation method followed by ultrasonication and characterized for particle size, polydispersity index, zeta potential, morphology, and structure. Moreover, the nasal formulations were characterized for drug loading, pH, particle size, viscosity, bioadhesive viscosity parameter, and were evaluated for in vitro dissolution and diffusion, in addition to in vivo studies in a rat model. Loratadine nanosuspension displayed a particle size of 311 nm, a polydispersity index of 0.16, and zeta potential of -22.05 mV. The nanosuspension preserved the crystalline status of the raw drug. The addition of sodium hyaluronate exhibited an increase in the mean particle size and zeta potential of the nanoparticles. The nasal formulations showed enhanced bioadhesive properties compared to the unprocessed loratadine in the reference samples. The nanosuspension based-formulation that contained 5 mg mL-1 sodium hyaluronate and 2.5 mg mL-1 loratadine (NF4) showed a significant enhancement of flux and permeability coefficient through a synthetic membrane. NF4 exhibited 24.73 µg cm-2 h-1 and 0.082 cm h-1, while the reference sample showed 1.49 µg cm-2 h-1 and 0.017 cm h-1, for the flux and the permeability coefficient, respectively. Nasal administration of NF4 showed a bioavailability of 5.54-fold relative to the oral administration. The results obtained in this study indicate the potential of the nasal route and the nanosuspension for loratadine delivery. The relative bioavailability of NF4 was 1.84-fold compared to unprocessed loratadine in the reference sample. Therefore, the nanosized loratadine could be suggested as a practical and simple nanosystem for the intranasal delivery with improved bioavailability.

Preparation and characterization of lamotrigine containing nanocapsules for nasal administration.

Nanocapsules (NCs) have become one of the most researched nanostructured drug delivery systems due to their advantageous properties and versatility. NCs can enhance the bioavailabiliy of hydrophobic drugs by impoving their solubility and permeability. Also, they can protect these active pharmaceutical agents (APIs) from the physiological environment with preventing e.g. the enzymatic degradation. NCs can be used for many administration routes: e.g. oral, dermal, nasal and ocular formulations are exisiting in liquid and solid forms. The nose is one of the most interesting alternative drug administration route, because local, systemic and direct central nervous system (CNS) delivery can be achived; this could be utilized in the therapy of CNS diseases. Therefore, the goal of this study was to design, prepare and investigate a novel, lamotrigin containing NC formulation for nasal administration. The determination of micrometric parameters (particle size, polydispersity index, surface charge), in vitro (drug loading capacity, release and permeability investigations) and in vivo characterization of the formulations were performed in the study. The results indicate that the formulation could be a promising alternative of lamotrigine (LAM) as the NCs were around 305 nm size with high encapsulation efficiency (58.44%). Moreover, the LAM showed rapid and high release from the NCs in vitro and considerable penetration to the brain tissues was observed during the in vivo study.

Development of Meloxicam-Human Serum Albumin Nanoparticles for Nose-to-Brain Delivery via Application of a Quality by Design Approach.

The aim of this study was to optimize the formulation of meloxicam (MEL)-containing human serum albumin (HSA) nanoparticles for nose-to-brain via a quality by design (QbD) approach. Liquid and dried formulations of nanoparticles containing Tween 80 and without the surfactant were investigated. Various properties, such as the Z-average, zeta potential, encapsulation efficacy (EE), conjugation of MEL and HSA, physical stability, in vitro dissolution, in vitro permeability, and in vivo plasma and brain distribution of MEL were characterized. From a stability point of view, a solid product (Mel-HSA-Tween) is recommended for further development since it met the desired critical parameters (176 ± 0.3 nm Z-average, 0.205 ± 0.01 PdI, -14.1 ± 0.7 mV zeta potential) after 6 months of storage. In vitro examination showed a significantly increased drug dissolution and permeability of MEL-containing nanoparticles, especially in the case of applying Tween 80. The in vivo studies confirmed both the trans-epithelial and axonal transport of nanoparticles, and a significantly higher cerebral concentration of MEL was detected with nose-to-brain delivery, in comparison with intravenous or per os administration. These results indicate intranasal the administration of optimized MEL-containing HSA formulations as a potentially applicable "value-added" product for the treatment of neuroinflammation.

An intraperitoneally administered pentapeptide protects against Abeta (1-42) induced neuronal excitation in vivo.

The underlying cause of Alzheimer's disease (AD) is thought to be the accumulation and aggregation of a misfolded protein, amyloid-beta (Abeta). A promising strategy against AD is the application of protective, peptide-based neuroprotective agents that selectively bind to Abeta. We recently described a pentapeptide, LPYFDa, which recognizes Abeta (1-42) and protects neurons against the toxic effects of aggregated Abeta (1-42) both in vitro and in vivo. Our previous work indicated that the in vivo ejection of fibrillar Abeta (1-42) into the hippocampal CA1 region resulted in a massive increase in the NMDA-evoked neuronal firing rate. Our current aim was to study whether intraperitoneally administered LPYFDa is capable of protecting against the synaptotoxic action of fibrillar Abeta (1-42) administered by iontophoresis. Our investigations of the in vivo biodistribution of tritium-labelled LPYFDa and single-unit electrophysiology revealed that LPYFDa readily crosses the blood-brain barrier, and protects the synapses against the excitatory action of fibrillar Abeta (1-42) in a relatively wide temporal window in rat. This pentapeptide may serve as a lead compound for the design of novel drug candidates for the prevention of AD.

Transformation of Meloxicam Containing Nanosuspension into Surfactant-Free Solid Compositions to Increase the Product Stability and Drug Bioavailability for Rapid Analgesia.

PURPOSE: The aim of this work was to study the influence of solidification of meloxicam (Mel) containing nanosuspension (nanoMel) on the physical stability and drug bioavailability of the products. The nanoMel sample had poly(vinyl alcohol) (PVA) as a protective polymer, but no surfactant as a further stabilizing agent because the final aim was to produce surfactant-free solid phase products as well. METHODS: The solidified samples produced by fluidization and lyophilization (fluidMel, lyoMel) were examined for particle size, crystallinity, and in vitro release of Mel compared to similar parameters of nanoMel. The products were subjected to an animal experiment using per oral administration to verify their bioavailability. RESULTS: Mel containing (1%) nanoMel sample was produced by wet milling process using an optimized amount of PVA (0.5%) which resulted in 130 nm as mean particle size and a significant reduction in the degree of crystallinity (13.43%) of Mel. The fluidization technique using microcrystalline cellulose (MCC) as carrier resulted in a quick conversion and no significant change in the critical product parameters. The process of lyophilization required a longer operation time, which resulted in the amorphization of the crystalline carrier (trehalose) and the recrystallization of Mel increased its particle size and crystallinity. The fluidMel and lyoMel samples had nearly five-fold higher relative bioavailability than nanoMel application by oral administration. The correlation between in vitro and in vivo studies showed that the fixed Mel nanoparticles on the surface of solid carriers (MCC, trehalose) in both the artificial gastric juice and the stomach of the animals rapidly reached saturation concentration leading to faster dissolution and rapid absorption. CONCLUSION: The solidification of the nanosuspension not only increased the stability of the Mel nanoparticles but also allowed the preparation of surfactant-free compositions with excellent bioavailability which may be an important consideration for certain groups of patients to achieve rapid analgesia.

Phytoecdysteroids and anabolic-androgenic steroids--structure and effects on humans.

Phytoecdysteroids are structural analogs of the insect molting hormone ecdysone. Plants comprise rich sources of ecdysteroids in high concentration and with broad structural diversity. Ecdysteroids have a number of proven beneficial effects on mammals but the hormonal effects of ecdysteroids have been proven only in arthropods. Their structures are somewhat similar to those of the vertebrate steroid hormones but there are several structural differences between the two steroid groups. Despite of these essential structural differences, ecdysteroids exert numerous effects in vertebrates that are similar to those of vertebrate hormonal steroids, and they may serve as effective anabolic, hepatoprotective, immunoprotective, antioxidant and hypoglycemic agents. Ecdysteroids do not bind to the cytosolic steroid receptors, instead, they are likely to influence signal transduction pathways, like the anabolic steroids, possibly via membrane bound receptors. The application of phytoecdysteroids is a promising alternative to the use of anabolic-androgenic steroids because of the apparent lack of adverse effects. The prospective use of phytoecdysteroids may extend to treatments of pathological conditions where anabolic steroids are routinely applied. One of the most cited aspects of phytoecdysteroid application (on the Internet) is the increase of muscle size. However in this field too stringent research is needed as an adequate cytological explanation is not yet available for the anabolic. This paper reports on the most important structural differences between androgenic hormones, their synthetic analogs and ecdysteroids. The anabolic/hormonal effects and the possible mechanisms of action of these compounds are also discussed as concerns the skeletal muscle.

[Formulation of an oral solid dosage form containing human interferon-alpha]. / Humán interferon-alpha orális szilárd gyógyszerformába történo feldolgozása.

The main objective of this study was to process the human alpha-interferon for the solid dosage form. The first step was the preparation of the intermediate product for the tablet making. Fluid bed apparatus with top spray method was applied for the layering of powdered cellulose with human alpha-interferon solutions. The intermediate product was compressed into tablet and an enteric solvent coating of the tablets was made in a fluid bed apparatus with Wurster method. The physical parameters were detected. These fitted the Ph. Eur. and the mechanical properties of the tablets were appropriate for coating in fluid bed apparatus. The tablets agree with the requirements of Ph. Eur. and the active agent was not dissolved in gastric juice. An animal test was also performed. The human alpha-interferon in the blood of the animals was detected with ELISA method. The human alpha-interferon specific kit was used. The active ingredient dissolved from the tablets was absorbed from the ileum. The solid dosage form containing human alpha-interferon was prepared; this can make oral application of human alpha-interferon possible.

3D QSAR models for alpha2a-adrenoceptor agonists.

Three-dimensional structure-activity relationship studies of alpha2a-adrenoceptor agonists were carried out by Distance Comparison (DISCOthech) and Comparative Molecular Field Analysis (CoMFA) methods to define the pharmacophore and a quantitative model, respectively, of this class of compounds. The statistical validation of the CoMFA model indicates its high predictive performance for binding affinities of new alpha2a-adrenoceptor agonists.

Receptor-based QSAR studies of non-peptide human oxytocin receptor antagonists.

In the present study, QSAR calculations were performed on the receptor-based alignment of 58 non-peptide human oxytocin receptor antagonists. With the aid of different scoring functions (AutoDock 3.05 built-in and X-Score 1.2) the evolved receptor-ligand complexes were characterized. By means of various datasets it was confirmed that the scoring functions were not capable to predict the biological activity correctly in compounds containing a rigid derivative in the variable region. To improve the pKi prediction 3D-QSAR calculation was performed. The regions related to the biological activity were determined by using cross-validated r2(q2)-guided region selection (q2-GRS) method. The predictive power of the CoMFA model [r(pred)2=0.89, q2(LMO, five groups)=0.695+/-0.034] allowed prediction of the biological activities of newly synthesized compounds and confirmed the receptor-based alignment.

Neighboring group participation. Part 16. Stereoselective synthesis and receptor-binding examination of the four stereoisomers of 16-bromomethyl-3,17-estradiols.

The four possible isomers of 3-benzyloxy-16-hydroxymethylestra-1,3,5(10)-trien-17-ol (1a-4a) with proven configurations were converted into the corresponding 3-benzyloxy-16-bromomethylestra-1,3,5(10)-triene-3,17-diols (5e-8e). Depending on the reaction conditions the cis isomers of 3-benzyloxy-16-hydroxymethylestra-1,3,5(10)-trien-17-ol (1a and 2a) were transformed into 3-benzyloxy-16-bromomethylestra-1,3,5(10)-trien-17-yl acetate (5b and 6b) or 16-bromomethyl-3-hydroxyestra-1,3,5(10)-trien-17-yl acetate (5c and 6c) on treatment with HBr and acetic acid. The mechanism of the process can be interpreted as involving front-side neighboring group participation. Under similar experimental conditions, the trans isomers (3a and 4a) yielded only 3-benzyloxy-16-acetoxymethylestra-1,3,5(10)-trien-17-yl acetates (3b and 4b) or 16-acetoxymethylestra-1,3,5(10)-triene-3,17-diyl diacetates (3d and 4d). Both the cis (1a and 2a) and the trans (3a, and 4a) isomers were transformed into 16-bromomethylestra-1,3,5(10)-trien-17-ol (5a-8a) by the Appel reaction on treatment with CBr4/Ph3P. Debenzylation of 5a-8a was carried out with HBr and acetic acid to yield 5e-8e. The debenzylation process in the presence of acetic anhydride produces the diacetates 5d-8d. The structures of the compounds were determined by means of MS, 1H NMR and 13C NMR spectroscopic methods. Compounds 5c-8c and 5e-8e were tested in a radioligand-binding assay. Except for the affinity of 7e for the estrogen receptor (Ki=2.55 nM), the affinities of the eight compounds (5c-8c and 5e-8e) for the estrogen, androgen and progesterone receptors are low (Ki > 0.55, 0.52 and 0.21 microM, respectively).

Effect of solubility enhancement on nasal absorption of meloxicam.

Besides the opioids the standard management of the World Health Organization suggests NSAIDs (non-steroidal anti-inflammatory drugs) alone or in combination to enhance analgesia in malignant and non-malignant pain therapy. The applicability of NSAIDs in a nasal formulation is a new approach in pharmaceutical technology. In order to enhance the nasal absorption of meloxicam (MX) as an NSAID, its salt form, meloxicam potassium monohydrate (MXP), registered by Egis Plc., was investigated in comparison with MX. The physico-chemical properties of the drugs (structural analysis, solubility and dissolution rate) and the mucoadhesivity of nasal formulations were controlled. In vitro and in vivo studies were carried out to determine the nasal applicability of MXP as a drug candidate in pain therapy. It can be concluded that MX and MXP demonstrated the same equilibrium solubility at the pH5.60 of the nasal mucosa (0.017mg/ml); nonetheless, MXP indicated faster dissolution and a higher permeability through the synthetic membrane. The animal studies justified the short Tmax value (15min) and the high AUC of MXP, which is important in acute pain therapy. It can be assumed that the low mucoadhesivity of MXP spray did not increase the residence time in the nasal cavity, and the elimination from the nasal mucosa was therefore faster than in the case of MX. Further experiments are necessary to prove the therapeutic relevance of this MXP-containing innovative intranasal formulation.

Study of sodium hyaluronate-based intranasal formulations containing micro- or nanosized meloxicam particles.

This article reports on the micro- and nanonization of meloxicam (MEL) with the aim of developing pre-dispersions as intermediates for the design of intranasal formulations. As a new approach, combined wet milling technology was developed in order to reduce the particle size of the MEL. Different milling times resulted in micro- or nanosized MEL in the pre-dispersions with polyvinyl alcohol as stabilizer agent, which were directly used for preparing intranasal liquid formulations with the addition of sodium hyaluronate as mucoadhesive agent. Reduction of the MEL particle size into the nano range led to increased saturation solubility and dissolution velocities, and increased adhesiveness to surfaces as compared with microsized MEL particles. A linear correlation was demonstrated between the specific surface area of MEL and the AUC. The in vitro and in vivo studies indicated that the longer residence time and the uniform distribution of nano MEL spray throughout an artificial membrane and the nasal mucosa resulted in better diffusion and a higher AUC. Nanosized MEL may be suggested for the development of an innovative dosage form with a different dose of the drug, as a possible administration route for pain management.

Alpha-adrenergic blockade: a possible mechanism of tocolytic action of certain benzodiazepines in a postpartum rat model in vivo.

Benzodiazepines are frequently used for the treatment of maternal psychiatric disorders during pregnancy. Besides their anxiolytic effect, they are reported to exert a direct relaxing action on several smooth muscle preparations, including the uterus. In the present study, the possibility of the involvement of alpha(1)-adrenergic receptors in this peripheral effect is investigated. The tocolytic potencies of diazepam, midazolam and nitrazepam are assessed in vivo in a postpartum rat model, together with other drugs known to bind to alpha-adrenoceptors (e.g. alpha(1)-antagonists, tricyclic compounds and droperidol). The interactions of some benzodiazepines and norepinephrine were also examined in an isolated in vitro system. The affinities of these agents for the receptor in question were additionally tested by radioligand displacement assay. A correlation was found between the tocolytic potencies and inhibition constants of the tested drugs, suggesting that the smooth muscle-relaxing effect of these benzodiazepines is mediated through modulation of the alpha(1)-adrenergic receptors.

Synthesis and receptor-binding examination of 16-hydroxymethyl-3,17-estradiol stereoisomers.

The four 16-hydroxymethylestra-1,3,5(10)-triene-3,17-diol isomers were synthesized and tested in a radioligand-binding assay. The estrogen receptor recognizes these compounds, but their relative binding affinities are lower than 2.0% relative to that of the reference molecule estra-1,3,5(10)-triene-3,17beta-diol. The affinities of the tested compounds for the androgen and progesterone receptors are very low (K(i)> 100 microm and 1 microM, respectively). The prepared 16-hydroxymethylestra-1,3,5(10)-triene-3,17-diol isomers are therefore estrogen receptor-selective molecules.

Synthesis and receptor-binding examinations of the normal and 13-epi-D-homoestrones and their 3-methyl ethers.

An effective epimerization of the normal estrone 3-methyl and 3-benzyl ethers by using o-phenylenediamine and AcOH made the possibility for facile entry into the 13alpha-estrone series. Combination of this synthetic methodology with an isolation step carried out by means of the Girard-P reagent, the corresponding ethers of 13-epi-estrone were obtained in excellent yields. The 3-hydroxy and 3-methoxy D-homoestrone derivatives in both the normal and the 13alpha-estrone series were then synthesized and tested in vitro in a radioligand-binding assay. The estrogen receptor recognizes these compounds, but their relative binding affinities (RBAs) are lower than that of the reference compound 3,17beta-estradiol. The progesterone receptor-binding affinities of the four D-homo derivatives were also tested showing low values for 13alpha-D-homoestrone and its 3-methyl ether. Pharmacologically, these 13alpha-D-homoestrone derivatives are estrogen receptor-selective molecules.

Synthesis and receptor-binding examination of 16-hydroxymethyl-3,17-estradiol stereoisomers.

The four 16-hydroxymethylestra-1,3,5(10)-triene-3,17-diol isomers were synthesized and tested in a radioligand-binding assay. The estrogen receptor recognizes these compounds, but their relative binding affinities are lower than 2.0% relative to that of the reference molecule estra-1,3,5(10)-triene-3,17beta-diol. The affinities of the tested compounds for the androgen and progesterone receptors are very low (K(i)> 100 microm and 1 microM, respectively). The prepared 16-hydroxymethylestra-1,3,5(10)-triene-3,17-diol isomers are therefore estrogen receptor-selective molecules.