Aqueous cannabidiol ß-cyclodextrin complexed polymeric micelle nasal spray to attenuate in vitro and ex vivo SARS-CoV-2-induced cytokine storms.

Cannabidiol (CBD) has a number of biological effects by acting on the cannabinoid receptors CB1 and CB2. CBD may be involved in anti-inflammatory processes via CB1 and CB2 receptors, resulting in a decrease of pro-inflammatory cytokines. However, CBD's poor aqueous solubility is a major issue in pharmaceutical applications. The aim of the present study was to develop and evaluate a CBD nasal spray solution. A water-soluble CBD was prepared by complexation with ß-cyclodextrin (ß-CD) at a stoichiometric ratio of 1:1 and forming polymeric micelles using poloxamer 407. The mixture was then lyophilized and characterized using FT-IR, DSC, and TGA. CBD-ß-CD complex-polymeric micelles were formulated for nasal spray drug delivery. The physicochemical properties of the CBD-ß-CD complex-polymeric micelle nasal spray solution (CBD-ß-CDPM-NS) were assessed. The results showed that the CBD content in the CBD-ß-CD complex polymeric micelle powder was 102.1 ± 0.5% labeled claim. The CBD-ß-CDPM-NS was a clear colorless isotonic solution. The particle size, zeta potential, pH value, and viscosity were 111.9 ± 0.7 nm, 0.8 ± 0.1 mV, 6.02 ± 0.02, and 12.04 ± 2.64 cP, respectively. This formulation was stable over six months at ambient temperature. The CBD from CBD-ß-CDPM-NS rapidly released to 100% within 1 min. Ex vivo permeation studies of CBD-ß-CDPM-NS through porcine nasal mucosa revealed a permeation rate of 4.8 µg/cm2/min, which indicated that CBD was effective in penetrating nasal epithelial cells. CBD-ß-CDPM-NS was tested for its efficacy and safety in terms of cytokine production from nasal immune cells and toxicity to nasal epithelial cells. The CBD-ß-CDPM-NS was not toxic to nasal epithelial at the concentration of CBD equivalent to 3.125-50 µg/mL. When the formulation was subjected to bioactivity testing against monocyte-like macrophage cells, it proved that the CBD-ß-CDPM-NS has the potential to inhibit inflammatory cytokines. CBD-ß-CDPM-NS demonstrated the formulation's ability to reduce the cytokine produced by S-RBD stimulation in ex vivo porcine nasal mucosa in both preventative and therapeutic modes.

Oral inhalation of cannabidiol delivered from a metered dose inhaler to alleviate cytokine production induced by SARS-CoV-2 and pollutants.

Cannabidiol (CBD) was formulated as a metered dose inhaler (CBD-MDI) and evaluated in vitro for its efficacy as an inhaled dosage form against inflammation caused by the SARS-CoV-2 virus, lipopolysaccharide (LPS) from Escherichia coli, silica particles, nicotine, and coal tar. A CBD-MDI formulation was prepared with 50 mg of CBD in 10 mL for a CBD dose of 250 µg/puff. The formulation ingredients included CBD, absolute ethanol as a cosolvent, and HFA-134a as the propellant. High aerosol performance of CBD-MDI was obtained with mass median aerodynamic diameter of 1.25 ± 0.01 µm, geometric standard deviation of 1.75 ± 0.00, emitted dose of 244.7 ± 2.1 µg, and fine particle dose of 122.0 ± 1.6 µg. The cytotoxicity and anti-inflammatory effectiveness of CBD-MDI were performed in alveolar macrophage (NR8383) and co-culture of alveolar macrophage (NR8383) and human lung adenocarcinoma (A549) cell line. CBD delivered from an MDI was safe on respiratory cells and did not trigger an immune response in alveolar macrophages. CBD-MDI effectively reduced the generation of cytokines in immune cells treated with viral antigen S-RBD, bacterial antigen LPS, silica particles, and coal tar. The efficacy of CBD-MDI was comparable to budesonide. Furthermore, the findings demonstrated that the use of CBD-MDI was more effective in treatment rather than prevention when inflammation was induced by either a viral or bacterial stimulant.

Biomimetic sensors targeting oxidized-low-density lipoprotein with molecularly imprinted polymers.

Oxidized-low-density lipoprotein (oxLDL) is well-recognized as an actual patho-atherogenic lipoprotein: elevated serum concentration of oxLDL increases the risk for developing atherosclerosis, leading to coronary artery disease (CAD). Herein, we report an approach for sensing oxLDL directly in serum with molecularly imprinted polymer (MIP) thin films on quartz crystal microbalance (QCM). The resulting MIP sensors show low cross-reaction toward low-density lipoprotein (LDL) and high-density lipoprotein (HDL): signals are around one magnitude smaller. Very-low-density lipoprotein (VLDL) and human serum albumin (HSA) do not lead to any significant sensor response. The sensor allowed for accurately assessing oxLDL over the detection range of 86-5600 µg dL-1, which covers the clinically relevant concentrations. The sensor determines oxLDL with recovery accuracy of 92-107% and a precision of 1-8% coefficient variation. Compared with commercially available oxLDL ELISA test kit our sensor reveals similar characteristics obtaining a correlation coefficient of 0.98. However, the sensors have rapid response times of 10 min compared to 210 min of ELISA, which demonstrates their efficiency in assessing this sensitive atherogenic biomarker for CAD diagnostics.

Effect of sodium deoxycholate sulfate on outer membrane permeability and neutralization of bacterial lipopolysaccharides by polymyxin B formulations.

We demonstrated binding interactions of polymyxin B (PMB), PMB formulations in the mole ratios of 1:2 and 1:3 of PMB:sodium deoxycholate sulfate (SDCS) and a commercial PMB formulation (CPMB) with lipopolysaccharides (LPS). The 1:2 PMB formulation (78.5-135.2 nM) exhibited a lower number of binding sites to the tested LPS compared to CPMB (112.6-140.9 nM) whereas 1:3 PMB formulation exhibited a higher number of binding sites (143.9-340.2 nM). Similarly, in the presence of LPS, the 1:2 PMB formulation (163.8-221.4 nm) exhibited smaller particle sizes compared to PMB, CPMB and 1:3 PMB formulation (248.8-603.5 nm). Molecular docking simulation suggested that the fatty acyl tails of LPS wrap together to produce a pseudo-globular structure of PMB-LPS complex, and among those 1:2 PMB formulation formed a more stable structure. The primary forces behind this complex are hydrogen bonds and salt bridges among the LPS, PMB, and SDCS. This study revealed that the PMB, CPMB, and PMB formulations inserted into the LPS micelles to disrupt the LPS membrane, whereas the SDCS may induce aggregation. The 1:2 PMB formulation also had higher bacterial uptake than other PMB formulations. The 1:2 PMB formulation neutralized the LPS micelles and was effective against Escherichia coli and Pseudomonas aeruginosa.

Novel adsorptive materials by adenosine 5'-triphosphate imprinted-polymer over the surface of polystyrene nanospheres for selective separation of adenosine 5'-triphosphate biomarker from urine.

In this study, we have developed a method to assess adenosine 5'-triphosphate by adsorptive extraction using surface adenosine 5'-triphosphate-imprinted polymer over polystyrene nanoparticles (412 ± 16 nm) for selective recognition/separation from urine. Molecularly imprinted polymer was synthesized by emulsion copolymerization reaction using adenosine 5'-triphosphate as a template, functional monomers (methacrylic acid, N-isopropyl acrylamide, and dimethylamino ethylmethacrylate) and a crosslinker, methylenebisacrylamide. The binding capacities of imprinted and non-imprinted polymers were measured using high-performance liquid chromatography with UV detection with a detection limit of 1.6 ± 0.02 µM of adenosine 5'-triphosphate in the urine. High binding affinity (QMIP , 42.65 µmol/g), and high selectivity and specificity to adenosine 5'-triphosphate compared to other competitive nucleotides including adenosine 5'-diphosphate, adenosine 5'-monophosphate, and analogs such as adenosine, adenine, uridine, uric acid, and creatinine were observed. The imprinting efficiency of imprinted polymer is 2.11 for urine (QMIP , 100.3 µmol/g) and 2.51 for synthetic urine (QMIP , 48.5 µmol/g). The extraction protocol was successfully applied to the direct extraction of adenosine 5'-triphosphate from spiked human urine indicating that this synthesized molecularly imprinted polymer allowed adenosine 5'-triphosphate to be preconcentrated while simultaneously interfering compounds were removed from the matrix. These submicron imprinted polymers over nano polystyrene spheres have a potential in the pharmaceutical industries and clinical analysis applications.

Binding interactions of bacterial lipopolysaccharides to polymyxin B in an amphiphilic carrier 'sodium deoxycholate sulfate'.

This work presents the outcomes of a comparative study of molecular interactions of polymyxin B (PMB) and F12 and F13 formulations in the mole ratios of 1:2 and 1:3 of PMB:sodium deoxycholate sulfate (SDCS), respectively, and a commercial PMB formulation (CPMB) with lipopolysaccharides (LPS). Several spectroscopic and interfacial studies were performed to obtain LPS-peptide interactions at a molecular level. The fluorescence titrimetry method revealed that the F12 formulation (325 nM) exhibited a lower number of binding sites to the LPS compared to CPMB and F13 as well as PMB alone (537 nM). Similarly, in the presence of LPS, the F12 formulation (88 nm) exhibited smaller particle sizes in the dynamic light scattering study compared to PMB (116 nm), CPMB, and the F13 formulation. An interfacial study and circular dichroism spectroscopy revealed PMB and CPMB insertion into the LPS micelles to destabilize and disrupt the LPS membrane, whereas the F12 and F13 formulations may induce pseudo-aggregation. The NMR and IR studies showed that the presence of SDCS, the hydrophobicity of PMB increased by hydrogen bonding and electrostatic interactions and formed stabilized PMB-SDCS micelles. The PMB-SDCS formulation is likely to release PMB for easy penetration into the lipid membrane and cause disruption of the complex LPS micelles. Furthermore, the PMB-SDCS formulations neutralized and detoxified the LPS micelles with minimal toxicity to normal kidney tubular cells as well as an immortalised kidney cell line. The antimicrobial properties of PMBloaded SDCS nanomicelles were effective against a resistant strain of Pseudomonas aeruginosa.

High-density lipoprotein sensor based on molecularly imprinted polymer.

Decreased blood level of high-density lipoprotein (HDL) is one of the essential criteria in diagnosing metabolic syndrome associated with the development of atherosclerosis and coronary heart disease. Herein, we report the synthesis of a molecularly imprinted polymer (MIP) that selectively binds HDL, namely, HDL-MIP, and thus serves as an artificial, biomimetic sensor layer. The optimized polymer contains methacrylic acid and N-vinylpyrrolidone in the ratio of 2:3, cross-linked with ethylene glycol dimethacrylate. On 10 MHz dual electrode quartz crystal microbalances (QCM), such HDL-MIP revealed dynamic detection range toward HDL standards in the clinically relevant ranges of 2-250 mg/dL HDL cholesterol (HDL-C) in 10 mM phosphate-buffered saline (PBS, pH = 7.4) without significant interference: low-density lipoprotein (LDL) yields 5% of the HDL signal, and both very-low-density lipoprotein (VLDL) and human serum albumin (HSA) yield 0%. The sensor reveals recovery rates between 94 and 104% at 95% confidence interval with precision of 2.3-7.7% and shows appreciable correlation (R 2 = 0.97) with enzymatic colorimetric assay, the standard in clinical tests. In contrast to the latter, it achieves rapid results (10 min) during one-step analysis without the need for sample preparation. Graphical Abstract ᅟ.

Improvement in insulin absorption into gastrointestinal epithelial cells by using molecularly imprinted polymer nanoparticles: Microscopic evaluation and ultrastructure.

A molecularly imprinted polymer nanoparticle (MIP) was prepared by integrating a mixed functional monomer into a highly cross-linked polymer. The nanosized insulin as a template transferred into the binding cavities, anchored functional monomer(s) that the insulin structure formed within free space of the molecular size region by MIP nanoparticles. The oral administration with the insulin-loaded MIP resulted in higher fluorescence intensity of rhodamine-labeled insulin into the epithelial cells. We observed the correlation between the lipophilic domains of dye over the affected areas of sites with the interplay of the intestinal epithelial layer on the different intestinal sections. And, the detection with guinea pig anti-insulin antibody followed by goat anti-guinea pig antibody clearly elicited the efficient insulin function in the necessary biological milieu. The root mean square roughness of the MIP indicated difference of the surface density, significantly lower compared with the polymer attributed to the protein-mucin uptake that efficiently promoted the insulin penetration. Eventually electron microscopy data of the conjugated biotin-gold nanoparticles showed the transport of insulin across the intestinal epithelium via transcellular pathway, and the development of the pancreatic ß cell in the streptozocin-induced diabetic rats. Histopathological observation exhibited no obvious toxic effect after orally treated with MIP loaded insulin (100mg/kg) daily for 14days compared to control group. The use of an insulin-loaded MIP was proven to be an effective therapeutic protein delivery through transmucosal oral route.

Biomimetic insulin-imprinted polymer nanoparticles as a potential oral drug delivery system.

In this study, we investigate molecularly imprinted polymers (MIPs), which form a three-dimensional image of the region at and around the active binding sites of pharmaceutically active insulin or are analogous to b cells bound to insulin. This approach was employed to create a welldefined structure within the nanospace cavities that make up functional monomers by cross-linking. The obtained MIPs exhibited a high adsorption capacity for the target insulin, which showed a significantly higher release of insulin in solution at pH 7.4 than at pH 1.2. In vivo studies on diabetic Wistar rats showed that the fast onset within 2 h is similar to subcutaneous injection with a maximum at 4 h, giving an engaged function responsible for the duration of glucose reduction for up to 24 h. These MIPs, prepared as nanosized material, may open a new horizon for oral insulin delivery.

Dopaminergic receptor-ligand binding assays based on molecularly imprinted polymers on quartz crystal microbalance sensors.

Molecularly imprinted polymers (MIPs) have been successfully applied as selective materials for assessing the binding activity of agonist and antagonist of dopamine D1 receptor (D1R) by using quartz crystal microbalance (QCM). In this study, D1R derived from rat hypothalamus was used as a template and thus self-organized on stamps. Those were pressed into an oligomer film consisting of acrylic acid: N-vinylpyrrolidone: N,N'-(1,2-dihydroxyethylene) bis-acrylamide in a ratio of 2:3:12 spin coated onto a dual electrode QCM. Such we obtained one D1R-MIP-QCM electrode, whereas the other electrode carried the non-imprinted control polymer (NIP) that had remained untreated. Successful imprinting of D1R was confirmed by AFM. The polymer can re-incorporate D1R leading to frequency responses of 100-1200Hz in a concentration range of 5.9-47.2µM. In a further step such frequency changes proved inherently useful for examining the binding properties of test ligands to D1R. The resulting mass-sensitive measurements revealed Kd of dopamine∙HCl, haloperidol, and (+)-SCH23390 at 0.874, 25.6, and 0.004nM, respectively. These results correlate well with the values determined in radio ligand binding assays. Our experiments revealed that D1R-MIP sensors are useful for estimating the strength of ligand binding to the active single site. Therefore, we have developed a biomimetic surface imprinting strategy for QCM studies of D1R-ligand binding and presented a new method to ligand binding assay for D1R.

Low-Density Lipoprotein Sensor Based on Molecularly Imprinted Polymer.

Increased level of low-density lipoprotein (LDL) strongly correlates with incidence of coronary heart disease. We synthesized novel molecularly imprinted polymers (MIP) as biomimetic specific receptors to establish rapid analysis of LDL levels. For that purpose the ratios of monomers acrylic acid (AA), methacrylic acid (MAA), and N-vinylpyrrolidone (VP), respectively, were screened on 10 MHz dual-electrode quartz crystal microbalances (QCM). Mixing MAA and VP in the ratio 3:2 (m/m) revealed linear sensor characteristic to LDL cholesterol (LDL-C) from 4 to 400 mg/dL or 0.10-10.34 mmol/L in 100 mM phosphate-buffered saline (PBS) without significant interference: high-density lipoprotein (HDL) yields 4-6% of the LDL signal, very-low-density-lipoprotein (VLDL) yields 1-3%, and human serum albumin (HSA) yields 0-2%. The LDL-MIP sensor reveals analytical accuracy of 95-96% at the 95% confidence interval with precision at 6-15%, respectively. Human serum diluted 1:2 with PBS buffer was analyzed by LDL-MIP sensors to demonstrate applicability to real-life samples. The sensor responses are excellently correlated to the results of the standard technique, namely, a homogeneous enzymatic assay (R(2) = 0.97). This demonstrates that the system can be successfully applied to human serum samples for determining LDL concentrations.

Development of a rubber elongation factor, surface-imprinted polymer-quartz crystal microbalance sensor, for quantitative determination of Hev b1 rubber latex allergens present in natural rubber latex products.

Molecularly imprinted polymers (MIPs) for screening to detect rubber latex allergens (Hev b1) in natural rubber based products were designed as artificial recognition polymeric materials coated onto a quartz crystal microbalance (QCM). The polymers were prepared using a stamp imprinting procedure after mixing optimum amounts of methacrylic acid-vinylpyrrolidone-dihydroxyethylene bisacrylamide and Hev b1 latex allergen proteins, obtained from rubber gloves. QCM measurements showed that the resulting polymer layers after removal of the proteins used in their preparation could incorporate structures and features down to nanometer scale of protein templates into the imprinted polymer much better than a non-specific control polymer under controlled sensor conditions and an optimized polymerization process. This selective polymer but not the non-selective polymer clearly distinguished between the latex allergen Hev b1 and proteins such as lysozyme, ovalbumin and bovine serum albumin, with a selectivity factor of from 2 to 4, and the response of the rubber elongation factors by an astonishing factor of 12. The imprinted cavities recognized specific binding sites and could distinguish among related hevein latex allergenic proteins isolated from fresh natural rubber latex; Hev b1, Hev b2, and Hev b3 with a selectivity factor of from 4 to 6. The different QCM measurements obtained presumably reflected slightly different conformations and affinities to the MIP binding sites. The sensor layers selectively adsorbed Hev b1 within minutes in amounts ranging from 10 to 1500 µg L⁻¹ and with a detection limit of 1 µg L⁻¹. This work has demonstrated that this new sensor provides a fast and reliable response to natural rubber latex protein, even after being extracted from the matrix of rubber gloves.

Interdigitated capacitive biosensor based on molecularly imprinted polymer for rapid detection of Hev b1 latex allergen.

Allergen protein detection was performed by a surface imprinted layer combined with an interdigitated capacitance (IDC) transducer that allowed label-free measurements. The immobilized imprinted polymers are the probes that bind to rubber allergen proteins extracted from products such as rubber gloves. Copolymers made from methacrylic acid-vinylpyrrolidone-dihydroxyethylene-bisacrylamide (MAA-NVP-DHEBA) are soluble in aqueous solution and eliminate the denaturation of protein. When deposited as a coating onto an IDC microelectrode transduction system, such materials lead to sensors that produce capacitance responses that are clearly dependent on the concentration of the latex protein (10-900 ng ml(-1)) in pH 7.4 buffer. The biosensor can detect Hev b1 within minutes and with a detection limit of 10 ng ml(-1). Different but related hevein allergenic proteins isolated from natural rubber latex from the rubber tree (Hev b1, Hev b2, and Hev b3) were distinguished by the imprinted material, depending on the dimension and conformation of these proteins with a selectivity factor of 4. They recognized Hevea latex proteins better than non-Hev b proteins, such as lysozyme, ovalbumin, and bovine serum albumin, by a factor of 2. Moreover, the sensor exhibited good operational stability of up to 180 days when used continuously at room temperature.

Interaction of Amphotericin B with cholesteryl palmityl carbonate ester.

A cholesteryl carbonate ester was prepared and evaluated as a possible thermotropic liquid crystal excipient for dry powder inhalers. Cholesteryl palmityl carbonate (CPC) was synthesized, and the phase behavior was characterized by differential scanning calorimetry, transmission electron microscopy, polarized light microscope, small angle X-ray diffraction, and solid-state nuclear magnetic resonance spectroscopy. Amphotericin B (AmB) was incorporated into CPC at various mole% (7.7, 14.3, 25, 33.3, and 50) using a solvent evaporation method. The amount of AmB loaded into liquid crystal was limited. The mixture of AmB in liquid crystal did not produce a new complex; rather, the addition of AmB affected the orientational order and the motional aspects of liquid crystal molecules.

Development of a pH-responsive drug delivery system for enantioselective-controlled delivery of racemic drugs.

This study aimed to develop enantioselective-controlled drug delivery systems for selective release of the required (S)-enantiomer in a dose formulation containing a racemic drug in response to pH stimuli. The recognition system was obtained from a nanoparticle-on-microsphere (NOM) molecularly imprinted polymer (MIP) with a multifunctional chiral cinchona anchor synthesised by suspension polymerisation using ethylene glycol dimethacrylate as a cross-linker. (S)-omeprazole was used as an imprinting molecule conferring stereoselectivity upon the polymers. The ability of the prepared recognition polymers to selectively rebind (S)-omeprazole was evident at different pH levels (the highest being at pH 7.4). The partial selective-release phenomenon of the (S)-enantiomer in MIP-containing composite cellulose membranes with increased vehicular racemic omeprazole concentrations was highly pH-dependent. Cinchona-bonded polymers imprinted with (S)-omeprazole could recognise the moldable contact site of (S)-omeprazole independently of its chirality; this is responsible for the delivery of (S)-enantiomer from racemic omeprazole. The controlled-release drug devices were fabricated with synthesised composite latex, and consisted of a pH stimuli-responsive poly(hydroxyethyl methacrylate) (HEMA) and polycaprolactone-triol (PCL-T) blend, and a MIP with preloaded drug, along with pH 7.4 buffer in the device's interior. The results demonstrate that drug delivery systems containing (S)-omeprazole imprinted cinchona-polymer nanoparticle-on-microspheres may maximise efficacy while minimising dose frequency.

Development of a reservoir-type transdermal enantioselective-controlled delivery system for racemic propranolol using a molecularly imprinted polymer composite membrane.

The aims of this study were to develop a transdermal patch for selective controlled delivery of the active S-enantiomer from racemic propranolol, and to evaluate its performance in vivo using Wistar rats. A molecularly imprinted polymer (MIP) thin-layer composited cellulose membrane with selectivity for S-propranolol was employed as the enantioselective-controlled release system. The effect of gel reservoir (poloxamer and chitosan) on enantioselective delivery was investigated. The chitosan gel allowed excellent selectivity for delivery of the S-propranolol enantiomer, whilst the more rheologically structured poloxamer gel formulation provided no selective release of S-propranolol. The chitosan gel exhibited high flux and had the ability to enantioselective deliver S-propranolol across excised rat skin. The results from confocal laser scanning microscopy study, carried out with the R- and S-propranolol enantiomers labeled with a 1-pyrenebutyric acid probe as fluorescent markers, suggested that the MIP composite membrane selectively regulated the release of the recognised S-enantiomer via a facilitated transport pathway through complex formation with the selective receptor sites, while the release of the R-enantiomer was via a non-selective route. The reservoir patch for enantiomer-controlled delivery of propranolol was therefore fabricated by incorporating the chitosan gel formulation containing racemic propranolol hydrochloride into the MIP composite membrane laminated backing. These patch devices were shown to exhibit the significant stereoselectivity uptake of propranolol when attached to the skin, using pharmacokinetic studies in rats. S-Propranolol enantiomer plasma concentration profiles for the transdermal patch in the in vivo study were comparable to data for the gel formulations that were applied directly to skin, and containing a single S-enantiomer of propranolol. The results demonstrate that the transdermal patch based on the MIP composite membrane-controlled release system may have potential in the enantioselective-controlled delivery of the S-isomer of racemic propranolol.

Recognition properties and competitive assays of a dual dopamine/serotonin selective molecularly imprinted polymer.

A molecularly imprinted polymer (MIP) with dual dopamine/serotonin-like binding sites (DS-MIP) was synthesized for use as a receptor model of study the drug-interaction of biological mixed receptors at a molecular level. The polymer material was produced using methacrylic acid (MAA) and acrylamide (ACM) as functional monomers, N,N'-methylene bisacrylamide (MBAA) as cross-linker, methanol/water mixture (4:1, v/v) as porogen and a mixture of dopamine (D) and serotonin (S) as templates. The prepared DS-MIP exhibited the greatest rebinding of the template(s) in aqueous methanol solution with decreased recognition in acetonitrile, water and methanol solvent. The binding affinity and binding capacity of DS-MIP with S were found to be higher than those of DS-MIP with D. The selectivity profiles of DS-MIP suggest that the D binding site of DS-MIP has sufficient integrity to discriminate between species of non-optimal functional group orientation, whilst the S binding site of DS-MIP is less selective toward species having structural features and functional group orientations different from S. The ligand binding activities of a series of ergot derivatives (ergocryptine, ergocornine, ergocristine, ergonovine, agroclavine, pergolide and terguride) have been studied with the DS-MIP using a competitive ligand binding assay protocol. The binding affinities of DS-MIP were demonstrated in the micro- or submicro-molar range for a series of ergot derivatives, whereas the binding affinities were considerably greater to natural receptors derived from the rat hypothalamus. The DS-MIP afforded the same pattern of differentiation as the natural receptors, i.e. affinity for the clavines > lysergic acid derivatives > ergopeptines. The results suggest that the discrimination for the ergot derivatives by the dopamine and serotonin sites of DS-MIP is due to the structural features and functional orientation of the phenylethylamine and indolylethylamine entities at the binding sites, and the fidelity of the dopamine and serotonin imprinted cavities.

S-propranolol imprinted polymer nanoparticle-on-microsphere composite porous cellulose membrane for the enantioselectively controlled delivery of racemic propranolol.

Molecularly imprinted polymer (MIP) nanoparticle-on-microspheres (NOM) selective for S-propranolol were successfully prepared using suspension polymerization involving agitation of the reaction mixture at high speed. The integration of the MIP-NOM into a self-assembled porous cellulose membrane allowed a controlled distribution and availability of the molecule recognition sites within a porous structure. The nature of the membrane-included microparticles determined the degree of porosity whilst the adherent nanoparticles provided an increased surface area enabling the composite membrane to be employed efficiently for the trans-membrane transport of the imprinted molecule. The MIP-NOM within the membrane were easily accessible for binding of the imprinted molecule and appeared to maintain high selectivity, indicating that the composite membranes may potentially provide valuable affinity matrices. In this study, the application for MIP-NOM composite cellulose membranes were investigated for their potential to act as transdermal drug delivery systems for the S-enantiomers from racemic propranolol, its ester prodrugs (cyclopropanoyl- and valeryl-propranolol) or other beta-blockers (pindolol and oxprenolol). The enantioselective release of the fluorescently active 1-pyrene-butyryl ester prodrug of S-propranolol from MIP-NOM composite membranes and its diffusion and transit across excised rat skin was monitored by confocal laser scanning microscopy. The mechanism underlying the release of S-propranolol from the MIP-NOM composite membrane was found to involve specific adsorption and mobility of this enantiomer at the binding site in the MIP-NOM as the latter undergo a transition from the dry to wet state. The proposed MIP-NOM composite membrane controlled release system may be applicable for fabrication of novel membranes with self-controllable permeability responding to the presence of target solutes.

The correlation of urinary levels of albuterol and its metabolites isomers following inhalation from a dry powder inhaler and in vitro particle size characterisation.

This study was designed to analyse the two enantiomers of abuterol in urine after the inhalation of a single dose of racemic albuterol from three dry powder inhalers by human volunteers. Urine samples were collected over 24h and analysed by HPLC-with fluorescence detection. Albuterol and its metabolites in urine could only have resulted from pulmonary absorption because gastrointestinal absorption was prevented. Unchanged albuterol and its conjugated metabolites were detected in the urine of healthy volunteers at much higher levels than in the urine of the asthmatics. Also, the amount of S-(+)-isomer excreted in urine was higher than that of the R-(--)-isomer. These differences did not arise as a consequence of either the formulation or the inter-conversion of two isomers in the urine. There is a relationship between the improvement of mid-expiratory flow (FEF(25-75)) and the amount of R-(--)-albuterol remaining to be excreted. The elimination rate constants of the parent drug in healthy volunteers of both R-(--)- and S-(+)-isomers were higher than those of the respective conjugated metabolites. The mean S/R ratio of the parent drug was about unity initially and increased to about 1.5 in the urine collected between 12 and 24h. The values of S/R ratio of the conjugated metabolites in the healthy volunteers were in the range 1.2-2.4, with the value increasing over the time of collection before reaching a plateau. This also occurred with the asthmatics, but the ratios were higher, in the range of 2.0-4.5. In summary, the urinary level of albuterol following in vivo inhalation was found to correlate with in vitro deposition data from the dry powder inhaler.

Composite membrane of bacterially-derived cellulose and molecularly imprinted polymer for use as a transdermal enantioselective controlled-release system of racemic propranolol.

A composite membrane for transdermal delivery of S-propranolol enantiomer was developed based on the controlled pore functionalization of bacterial cellulose membranes using a molecularly imprinted polymer (MIP) layer synthesis. The reactive pore-filling of an asymmetric porous cellulose membrane with a MIP thin-layer was effected using a silanized coupler as an additional anchor for the MIP. MIP thin-layers with specific binding sites for S-propranolol were synthesized by copolymerization of methacrylic acid with a cross-linker, ethylene glycol dimethacrylate in the presence of S-propranolol as the template molecule and the latter was subsequently extracted. Selective transport of S-propranolol through the MIP composite membrane was obtained, although this was determined mostly by the parent cellulose membrane with some ancillary contributory effect from the MIP layer. In addition, an enantioselectivity in the transport of propranolol prodrug enantiomers was found, suggesting that the shape and functional groups orientation, which are similar to that of the print molecule were essential for enantiomeric recognition of the MIP composite membrane. The enantioselectivity of S-MIP membranes was also shown when the release of propranolol enantiomers was studied in vitro using rat skin, with racemic propranolol contained in the donor compartment. The composite membrane of bacterially-derived cellulose and molecularly imprinted polymer may have great potential for use as a transdermal enantioselective controlled-release system for racemic propranolol.