Physicochemical properties and mechanisms of drug release from melt-extruded granules consisting of chlorpheniramine maleate and Eudragit FS.

The objective of this research project was to characterize the drug release profiles, physicochemical properties and drug-polymer interaction of melt-extruded granules consisting of chlorpheniramine maleate (CPM) and Eudragit® FS. Melt extrusion was performed using a single screw extruder at a processing temperature of 65-75 °C. The melt extrudate was milled, blended with lactose monohydrate and then filled into hard gelatin capsules. Each capsule contained 300 mg CPM granules. The release of CPM was determined with the United States Pharmacopeia dissolution apparatus II using a three-stage dissolution medium testing in order to simulate the pH conditions of the gastrointestinal tract. Pore structure, thermal properties and surface morphologies of CPM granules were studied using mercury and helium pycnometer, differential scanning calorimeter and scanning electron microscope. Sustained release of CPM over 10 h was achieved. The release of CPM was a function of drug loading and the size of the milled granules. The complexation between CPM and Eudragit® FS as the result of counterion condensation was observed, and the interaction was characterized using membrane dialysis and H(1) NMR techniques. In both 0.1 N HCl and phosphate buffer pH 6.8, CPM was released via a diffusion mechanism and the release rate was controlled by the pore structure of the melt-extruded granules. In phosphate buffer pH 7.4, CPM release was controlled by the low pH micro-environment created by CPM, the pore structure of the granules and the in situ complexation between CPM and Eudragit® FS.

Potential use of a megamolecular polysaccharide sacran as a hydrogel-based sustained release system.

A megamolecular polysaccharide sacran was newly extracted from cyanobacterium Aphanothece sacrum. Sacran has many preferable properties for transdermal application, e.g. a safe biomaterial, a high moisturizing effect, a formation of film and hydrogel. Additionally, it was recently discovered that sacran has an anti-inflammatory effect for atopic dermatitis model mice. In this study, in order to evaluate the feasibility of sacran-hydrogel as a novel sustained release system, we prepared a sacran-hydrogel containing 4-biphenyl acetic acid (BPAA, an acidic drug), prednisolone (PD, a neutral drug) or chlorpheniramine maleate (CPM, a basic drug), and performed the in vitro release studies. The sacran-hydrogel containing BPAA, PD or CPM provided a sustained release profile in accordance with a quasi-Fickian diffusion model. Furthermore, the release rate of drugs from sacran-hydrogels can be controlled by adjusting the concentration of aluminum chloride as a cross linker. These results suggest the potential use of sacran-hydrogel as a sustained release system for drugs.

Increased Nuclear FOXP2 Is Related to Reduced Neural Stem Cell Number and Increased Neurogenesis in the Dorsal Telencephalon of Embryos of Diabetic Rats through Histamine H1 Receptors.

Diabetic rat embryos have increased cortical neurogenesis and neuron maturation, and their offspring presented altered neuron polarity, lamination, and diminished neuron excitability. The FOXP2 overexpression results in higher cortical neurogenesis by increasing the transition of radial glia to the intermediate progenitor. Similarly, histamine through H1-receptor activation increases cortical neuron differentiation. Indeed, blocking the H1-receptor by the systemic administration of chlorpheniramine to diabetic pregnant rats prevents increased neurogenesis. Here, we explore the relationship between the H1-receptor and FOXP2 on embryo neurogenesis from diabetic dams. Through qRT-PCR, Western blot, immunohistofluorescence, and flow cytometry, we showed an increased FOXP2 expression and nuclear localization, a reduced Nestin expression and -positive cells number, and a higher PKCα expression in the cortical neuroepithelium of fourteen-day-old embryos from diabetic rats. Interestingly, this scenario was prevented by the chlorpheniramine systemic administration to diabetic pregnant rats at embryo day twelve. These data, together with the bioinformatic analysis, suggest that higher H1-receptor activity in embryos under high glucose increases FOXP2 nuclear translocation, presumably through PKCα phosphorylation, impairing the transition of radial glia to intermediate progenitor and increasing neuron differentiation in embryos of diabetic rats.

Quantification of chlorpheniramine maleate enantiomers by ultraviolet spectroscopy and chemometric methods.

Chlorpheniramine maleate (CLOR) enantiomers were quantified by ultraviolet spectroscopy and partial least squares regression. The CLOR enantiomers were prepared as inclusion complexes with beta-cyclodextrin and 1-butanol with mole fractions in the range from 50 to 100%. For the multivariate calibration the outliers were detected and excluded and variable selection was performed by interval partial least squares and a genetic algorithm. Figures of merit showed results for accuracy of 3.63 and 2.83% (S)-CLOR for root mean square errors of calibration and prediction, respectively. The ellipse confidence region included the point for the intercept and the slope of 1 and 0, respectively. Precision and analytical sensitivity were 0.57 and 0.50% (S)-CLOR, respectively. The sensitivity, selectivity, adjustment, and signal-to-noise ratio were also determined. The model was validated by a paired t test with the results obtained by high-performance liquid chromatography proposed by the European pharmacopoeia and circular dichroism spectroscopy. The results showed there was no significant difference between the methods at the 95% confidence level, indicating that the proposed method can be used as an alternative to standard procedures for chiral analysis.

Characterization of xenobiotic metabolizing enzymes in bovine small intestinal mucosa.

The intestinal mucosa plays a capital role in dictating the bioavailability of a large array of orally ingested drugs and toxicants. The activity and the expression of several xenobiotic metabolizing enzymes were measured in subcellular fractions from the duodenal mucosa of male veal calves and beef cattle displaying a functional rumen but differing in both age (about 8 months vs. 18 to 24 months) and dietary regimens (i.e., milk replacer plus hay and straw vs. corn and concentrated meal). Intestinal microsomes showed cytochrome P450 (CYP) 2B, 2C- and 3A-mediated activities and the presence of the corresponding immunorelated proteins, but no proof of CYP1A expression and/or functions could be provided. Intestinal microsomes were also active in performing reactions typically mediated by carboxylesterases (indophenylacetate hydrolysis), flavin-containing monooxygenases (methimazole S-oxidation), and uridindiphosphoglucuronyltransferases (1-naphthol glucuronidation), respectively. Cytosolic fractions displayed the glutathione S-transferase (GST)-dependent conjugation of 1-chloro-2,4-dinitrobenzene; besides, the GST-mediated conjugation of ethacrinic acid (GSTpi) or cumene hydroperoxide (GSTalpha) was matched by the presence of the corresponding immunorelated proteins. Conversely, despite the lack of measurable activity with 3,4-dichloronitrobenzene, a protein cross reacting with anti-rat GSTmu antibodies could be clearly detected. Although, as detected by densitometry, CYPs and GST isoenzymes tended to be more expressed in beef cattle than in veal calf preparations, there was a general poor correlation with the rate of the in vitro metabolism of the selected diagnostic probes.

Precision Printing of Customized Cylindrical Capsules with Multifunctional Layers for Oral Drug Delivery.

Advances in personalized medicine will require custom drug formulations and delivery mechanisms. Herein, we demonstrate a new type of personalized capsule comprising of printed concentric cylindrical layers with each layer having a distinctive functional drug component. Poly ε-caprolactone (PCL) with paracetamol (APAP) and chlorpheniramine maleate (CM), synergistic drugs commonly used to alleviate influenza symptoms, are printed as an inner layer and outer layer, respectively, via microscaled electrohydrodynamic (EHD) printing. Polyvinylpyrrolidone (PVP) nanofibers are embedded as interlayers between the two printed PCL-drug layers using electrospinning (ES) techniques. The complete concentric cylindrical capsule with a 6 mm inner diameter and 15 mm length can be swallowed for oral drug delivery. After dissolution of the PVP interlayer, the capsule separates in two, with inner and outer capsules for continuous drug dosing and targeting. Imaging was achieved using a 3T MRI system which allowed temporal observations of the targeted release through the incorporation of nanoparticles (Fe3O4). The morphology and structure, chemical composition, mechanical properties, and biocompatibility of the capsules were studied in vitro. In summary, this new type of custom printed and electrospun capsule that enabled component separation, targeted drug release may advance personalized medicine via multidrug oral delivery.

Development and evaluation of an oral fast disintegrating anti-allergic film using hot-melt extrusion technology.

The main objective of this novel study was to develop chlorpheniramine maleate orally disintegrating films (ODF) using hot-melt extrusion technology and evaluate the characteristics of the formulation using in vitro and in vivo methods. Modified starch with glycerol was used as a polymer matrix for melt extrusion. Sweetening and saliva-simulating agents were incorporated to improve palatability and lower the disintegration time of film formulations. A standard screw configuration was applied, and the last zone of the barrel was opened to discharge water vapors, which helped to manufacture non-sticky, clear, and uniform films. The film formulations demonstrated rapid disintegration times (6-11s) and more than 95% dissolution in 5min. In addition, the films had characteristic mechanical properties that were helpful in handling and storage. An animal model was employed to determine the taste masking of melt-extruded films. The lead film formulation was subjected to a human panel for evaluation of extent of taste masking and disintegration.

DNA-chlorpheniramine interaction studied by spectroscopic techniques.

It was previously studied that the antihistaminic chlorpheniramine elicits a biphasic response on cell growth and regulates polyamine metabolism, as described for polyamines. In part, polyamine effects on macromolecular synthesis and cell growth are attributed to nucleic acid:polyamine interactions. In this work, we have tested the hypothesis of a DNA:chlorpheniramine interaction, using fluorometry, FTIR and Raman spectroscopic techniques. The results indicate that DNA:chlorpheniramine interaction occurs inducing conformational changes in the macromolecule by affecting both phosphodiester bonds and bases. Results open new perspectives for characterization of action mechanisms of natural or synthetic diamines with pharmacological or physiological importance.

Carrier mediated transport of chlorpheniramine and chlorcyclizine across bovine olfactory mucosa: implications on nose-to-brain transport.

Delivery to the CNS via the nasal cavity has been pursued as a means to circumvent the blood-brain barrier (BBB), yet the mechanism of drug transport across this novel route is not well understood. Hydroxyzine and triprolidine have been reported to readily reach the CNS following nasal administration, whereas no measurable amounts of chlorcyclizine or chlorpheniramine, structurally similar antihistamines, were observed in the CSF. The permeation of chlorpheniramine and chlorcyclizine in vitro across the bovine olfactory mucosa was studied to investigate the biological and physicochemical characteristics that contribute to the limited CNS disposition of these compounds following nasal administration. The submucosal to mucosal fluxes (J(s-m)) of chlorcyclizine and chlorpheniramine across the olfactory mucosa were significantly greater than the mucosal to submucosal fluxes (J(m-s)). Moreover, the submucosal-mucosal permeability of both compounds was temperature dependent and saturable. In the presence of metabolic inhibitors (ouabain and 2,4-dinitrophenol) and P-glycoprotein (P-gp)/multidrug resistance protein 1 (MRP1) inhibitors (quinidine and verapamil), the J(m-s) increased and J(s-m) decreased significantly. These results indicate that chlorpheniramine and chlorcyclizine are effluxed from the olfactory mucosa by efflux transporters such as P-gp and MRP1. Transport studies across inert polymeric membranes demonstrated that the permeability of chlorpheniramine and chlorcyclizine decreased at donor concentrations higher than 3 mM suggesting that physicochemical properties such as self-aggregation also play a role in the reduced olfactory mucosal permeability of these compounds at higher concentrations.

Chlorpheniramine binding to human serum albumin by fluorescence quenching measurements.

The binding of chlorpheniramine to human serum albumin has been studied by fluorescence quenching, as a function of temperature; the experimental data could only be fitted to the Stern-Volmer modified equation. A statistical analysis of the results was performed in order to determine the significance of the constants calculated by this equation, as well as their thermodynamic parameters. The chlorpheniramine binding to human serum albumin accounts for almost half of the binding of this antihistaminic agent to human plasma proteins.

Sedation and histamine H1-receptor antagonism: studies in man with the enantiomers of chlorpheniramine and dimethindene.

1. The effects of 10 mg (+)- and (-)-chlorpheniramine and 5 mg (+)- and (-)-dimethindene on daytime sleep latencies, digit symbol substitution and subjective assessments of mood and well-being were studied in 6 healthy young adult humans. Each subject also took 5 mg triprolidine hydrochloride as an active control and two placebos. 2. Daytime sleep latencies were reduced with triprolidine, (+)-chlorpheniramine and (-)-dimethindene, and subjects also reported that they felt more sleepy after (+)-chlorpheniramine and (-)-dimethindene. Performance on digit symbol substitution was impaired with (+)-chlorpheniramine. 3. Changes in measures with (-)-chlorpheniramine and (+)-dimethindene were not different from changes with placebo. 4. In the present study, changes in measures of drowsiness and performance were limited to the enantiomers with high affinity for the histamine H1-receptor. These findings strongly suggest that sedation can arise from H1-receptor antagonism alone, and provide further support for the belief that the histaminergic system is concerned with the regulation of alertness in man.

In vitro metabolism of chlorpheniramine in the rabbit.

The in vitro metabolism of 3-(p-chlorophenyl)-3-(2-pyridyl)-N, N-dimethylpropylamine (chlorpheniramine, I) by rabbit liver microsomes was examined. The metabolites, tentatively identified by gas-liquid chromatography-mass spectrometry, included the mono- and didemethyl metabolites, the aldehyde that results from deamination, and further metabolites of this aldehyde including its intramolecular cyclization product, an indolizine, and its reduction product, the alcohol. Inhibition of metabolism of I by N2, CO, SKF-525A, 2,4-dichloro-6-phenylphenoxyethylamine (DPEA), or deletion of NADPH implies some involvement of cytochrome P-450 in the metabolic reactions. Quantitation of metabolism in these studies accounted for only 69% of the dose, so that binding and/or other undetected metabolic pathways were operative.

Characteristics of histamine H1 receptors on HeLa cells.

The affinities of antagonists at histamine H1 receptors on HeLa cells have been determined from inhibition of histamine-induced inositol phosphate formation in intact and from inhibition of [3H]mepyramine binding to HeLa cell membranes. The dissociation constants of mepyramine and (+)-chlorpheniramine were similar to values for binding to H1 receptors in other mammalian tissues, but much lower than the values reported in an earlier study with [3H]mepyramine and HeLa cell membranes. Evidence is presented that under conditions employed in the earlier study the binding of [3H]mepyramine is largely to secondary, non-H1 receptor sites.

Histamine H1-receptors labeled in vivo: antidepressant and antihistamine interactions.

3H-Mepyramine labels specific histamine H1-receptors in brains of mice after intravenous injection. The potencies of H1-antihistamines in reducing 3H-mepyramine binding in vivo correspond to their pharmacological activities and show parallels with their affinities for 3H-mepyramine binding sites in isolated brain membranes. Several antidepressants are potent in competing for 3H-mepyramine binding in vivo as well as in vitro.

Affinities of brompheniramine, chlorpheniramine, and terfenadine at the five human muscarinic cholinergic receptor subtypes.

Anticholinergic effects are presumed to be the mechanism for the efficacy of chlorpheniramine in symptomatic relief of the common cold. Terfenadine, a second-generation antihistamine, reportedly lacks anticholinergic side effects. We evaluated affinities of two commonly used over-the-counter antihistamines, brompheniramine and chlorpheniramine, as well as terfenadine in comparison with atropine at the five human muscarinic cholinergic receptor subtypes using CHO cells stably transfected with the individual subtypes. Atropine was more potent than all three drugs at m1-m5 (p<0.01). No significant difference was observed between chlorpheniramine and brompheniramine. Atropine, brompheniramine, and chlorpheniramine could not discriminate between m1-m5. Terfenadine demonstrated subtype selectivity at m3. In vitro comparisons in human muscarinic receptor subtypes could potentially be used to predict clinical anticholinergic effects of antihistamines and to target receptor-specific effects of such agents.

Separation of enantiomers on a chiral stationary phase based on ovoglycoprotein. II. Comparison of chiral recognition properties with crude ovomucoid.

Chiral stationary phases based on ovoglycoprotein from chicken egg whites (OGCHI) and crude ovomucoid from chicken egg whites (OMCHI) were compared with regard to the bound amounts of OGCHI and chiral recognition abilities. Crude OMCHI included 11% OGCHI, by weight. Since pure OMCHI had no appreciable chiral recognition ability, the chiral recognition ability of crude OMCHI originated from OGCHI, which was present in crude OMCHI preparations as an impurity. However, a chiral stationary phase based on crude OMCHI showed good chiral recognition ability, despite the 11% OGCHI content in crude OMCHI preparations. When crude OMCHI was reacted with N,N'-disuccinimidylcarbonate (DSC)-activated aminopropyl-silica gels, the ratio of bound OGCHI to that of totally bound protein was 0.23. These results reveal that the good chiral recognition ability of a stationary phase based on crude OMCHI is due to OGCHI being preferentially bound to DSC-activated aminopropyl-silica gels rather than the OMCHI. In addition, OMCHI did not contribute to the enantioselectivity of the solute at all and made little contribution to the retention characteristics.

Analysis of the binding of chlorpheniramine to human serum albumin by spectroscopic techniques.

The binding of chlorpheniramine (CFA) to human serum albumin (HSA) has been studied by absorption and fluorescence techniques. By deconvolution of the UV-spectra into five Gaussian bands it can be observed that the band at 214 nm is the most sensitive for following the interaction CFA-HSA. Such interaction causes a redshift in the band at 227 nm to 235 nm, and an isosbestic point surges at 236 nm. Moreover, the fluorescence quenching depends on the excitation wavelength. By excitation at 278 nm, 25% of the native fluorescence is quenched, but only 6% is quenched by excitation at 290 nm. From these spectroscopic studies our results are compatible with the possibility that the interaction could take place mainly on the subdomain IIIA.

Pharmacokinetics of intravenous chlorpheniramine in children.

The disposition of chlorpheniramine was examined in seven children, 6-14 years of age, following a 0.1 mg/kg iv dose. Postinjection serum chlorpheniramine levels in each subject declined biexponentially, with the greatest intersubject variability occurring in the initial distribution of the drug. The volume of distribution at steady state ranged from 1.20 to 5.46 liters/kg. The chlorpheniramine serum clearance varied approximately twofold (234-470 ml/hr/kg) and generally decreased with age. The chlorpheniramine elimination half-life in children (mean of 9.6 hr) appeared shorter than that in adults, probably due to higher chlorpheniramine serum clearance in children.

Bioavailability of regular and controlled-release chlorpheniramine products.

The bioavailability of chlorpheniramine regular-release versus controlled-release products was compared using 15 human subjects. The dosage forms evaluated were an 8-mg barrier coated-bead capsule, an 8-mg repeat action tablet, two 4-mg tablets, and 4- and 8-mg syrups. Single doses of each product were administered orally in a 5-way crossover study, plasma samples were collected at specific time intervals, and chlorpheniramine levels assayed by HPLC. Pharmacokinetic analysis was based on a two-compartment open model. The average plasma elimination half-life of chlorpheniramine was calculated to be approximately 18.3 hr. The controlled-release products gave a higher Cmax than the 4-mg syrup, but less than two 4-mg tablets. The controlled-release products also extended the time necessary to attain peak drug levels compared to the 4- and 8-mg syrups. The area under the curve (AUC) data for the controlled-release products was not equivalent to equal amounts of the regular-release products. The study indicated that while the controlled-release chlorpheniramine products were successful in prolonging the time course of absorption, this was at the expense of incomplete bioavailability of the drug.