Palladium (Pd) is extensively used in pharmaceutical small molecule drug substance processes, however it must be removed prior to release of the active pharmaceutical ingredient (API). Evaluation of four TXRF instruments and configurations were compared to ICP-MS instrumentation for trace metal analysis, most importantly for Pd. Standards and six pharmaceutical drug substances, triprolidine HCl, diphenhydramine HCl, chlorpheniramine maleate, pseudoephedrine HCl, ephedrine sulfate, and scopolamine HBr, were analyzed to determine linearity, sensitivity, accuracy, and precision for Pd plus Cr, Fe, Cu, Rh, and Pt versus interferences, particularly from Cl, S, and Ar, on the various X-ray fluorescence lines. Irrespective of instrument platform, in general X-ray sources capable of accessing Pd-K lines were found to be most effective in determination of Pd in APIs.

Human ether-a-go-go-related gene (hERG) channels play a critical role in cardiac action potential repolarization. The unintended block of hERG channels by compounds can prolong the cardiac action potential duration and induce arrhythmia. Several compounds not only block hERG channels but also enhance channel activation after the application of a depolarizing voltage step. This is referred to as facilitation. In this study, we tried to extract the property of compounds that induce hERG channel facilitation. We first examined the facilitation effects of structurally diverse hERG channel blockers in Xenopus oocytes. Ten of 13 assayed compounds allowed facilitation, suggesting that it is an effect common to most hERG channel blockers. We constructed a pharmacophore model for hERG channel facilitation. The model consisted of one positively ionizable feature and three hydrophobic features. Verification experiments suggest that the model well describes the structure-activity relationship for facilitation. Comparison of the pharmacophore for facilitation with that for hERG channel block showed that the spatial arrangement of features is clearly different. It is therefore conceivable that two different interactions of a compound with hERG channels exert two pharmacological effects, block and facilitation.

A novel non-stabilised aqueous suspension polymerisation methodology for the preparation of spherical molecularly imprinted polymers is described with chlorpheniramine (CP), d-chlorpheniramine (d-CP), brompheniramine (BP) and d-brompheniramine (d-BP) as the templates, respectively. Using this rapid and simple technique, controlled polymer beads in the low micron range with narrow size distributions were generated by photo-polymerisation. The use of agitation speed as a method of controlling bead size distribution was demonstrated. Enantioselective properties of the imprinted beads were examined and the polymers prepared using d-chlorpheniramine and d-brompheniramine were capable of discriminating between the enantiomers of the template. Cross-selectivity studies were performed by batch rebinding with the influence of template size and functional group orientation of analytes on the recognition properties of the imprinted polymers investigated. Physical characteristics of all polymers were studied by nitrogen sorption porosimetry, particle size analysis and scanning electron microscopy (SEM) in order to gain an insight into the role of such properties on retention behaviour.

N, N-nitrosodimethylamine (NDMA) is an emerging disinfection by-product (DBP) that has been widely detected in many drinking water systems and commonly associated with the chloramine disinfection process. Some amine-based pharmaceuticals have been demonstrated to form NDMA during chloramination, but studies regarding the reaction kinetics are largely lacking. This study investigates the NDMA formation kinetics from ranitidine, chlorphenamine, and doxylamine under practical chloramine disinfection conditions. The formation profile was monitored in both lab-grade water and real water matrices, and a statistical model is proposed to describe and predict the NDMA formation from selected pharmaceuticals in various water matrices. The results indicate the significant impact of water matrix components and reaction time on the NDMA formation from selected pharmaceuticals, and provide fresh insights on the estimation of ultimate NDMA formation potential from pharmaceutical precursors.

Nasal administration has been of special interest in the last decade due to its feasibility and relative high bioavailability compared to the oral rout of administration. Our study aimed to develop a nasal gel formulation for an antihistaminic drug, Chlorpheniramine maleate (CPM), which suffers from poor oral bioavailability (25-45%) due to its first-pass metabolism in the liver. Different formulations of CPM nasal gels were prepared using different polymers in different concentrations, these gels were evaluated for their in vitro (physico-chemical properties, release, permeability and stability) to select the best formulation which subject to in vivo tests including mucociliary clearance and bioavailability, both in comparison to the solution and commercial tablet Allergyl.

To develop the dual-drug resinate complexes containing codeine and chlorpheniramine with a novel batch processing, characterize the dual-drug resinate complexes, and study its drug release behavior in vitro. A procedure of simultaneous dual-drug loading using combination solutions composed of different proportions of codeine phosphate and chlorpheniramine maleate was performed to achieve the specific resinate, and the dual-drug loading content was determined by high-performance liquid chromatography method. The dual-drug resinate complexes were characterized by a scanning electron microscope, and the formation mechanisms were confirmed with X-ray diffraction analyses and differential scanning calorimetric analyses. The release behavior of the two drugs from the dual-drug resinate complexes in vitro was studied in the media simulating in vivo environments (simulated gastric fluid: pH = 1.2 HCl, simulated in vivo ionic strength: 0.15 M NaCl, and simulated intestinal fluid: pH = 6.8 buffer solution containing KH2PO4-NaOH). Scanning electron microscopic analyses proved that the dual-drug resinate complexes had the same appearance and characters as the initiative ion exchange resins (IERs). Via X-ray diffraction and differential scanning calorimetric analyses, it is found that the two drugs in dual-drug resinate complexes were combined with IERs by chemical bond. The drug-resinate complex, like IER, was in amorphous state. More than 90% of codeine phosphate was released in 15 minutes in three different media, whereas little amount of chlorpheniramine maleate was released in all the release time in the medium pH = 1.2 HCl, and the release equilibrium time was about 5 minutes, only 40% was released in the medium 0.15 M NaCl, and the equilibrium time was 40 minutes, and about 90% was released in the medium pH = 6.8 KH2PO4-NaOH. The increased ionic strength generally accelerated the release of the two drugs from the dual-drug resinate complexes. The dual-drug resinate complexes were formed through the reaction between the drugs and the IERs by chemical bond. The release behavior of the drug from the dual-drug resinate complexes in vitro was mainly correlated with the drug molecular structure, the eluting ionic strength, composition, and ionic strength of the release media. The novel dual-drug resinate complexes could be used to deliver two drugs in one therapeutic dose.

A sensitive and selective high performance liquid chromatography-peroxyoxalate chemiluminescence (PO-CL) method has been developed for the simultaneous determination of chlorpheniramine (CPA) and monodesmethyl chlorpheniramine (MDCPA) in human serum. The method combines fluorescent labeling with 4-(4,5-diphenyl-1H-imidazole-2-yl)phenyl boronic acid using Suzuki coupling reaction with PO-CL detection. CPA and MDCPA were extracted from human serum by liquid-liquid extraction with n-hexane. Excess labeling reagent, which interfered with trace level determination of analytes, was removed by solid-phase extraction using a C18 cartridge. Separation of derivatives of both analytes was achieved isocratically on a silica column with a mixture of acetonitrile and 60 mM imidazole-HNO(3) buffer (pH 7.2; 85:15, v/v) containing 0.015% triethylamine. The proposed method exhibited a good linearity with a correlation coefficient of 0.999 for CPA and MDCPA within the concentration range of 0.5-100 ng/mL. The limits of detection (S/N = 3) were 0.14 and 0.16 ng/mL for CPA and MDCPA, respectively. Using the proposed method, CPA could be selectively determined in human serum after oral administration.

The objectives of this study were to assess the utility of near infrared (NIR) spectroscopy for simultaneous in-line quantification of the contents of drug and excipients in tablets and to monitor the tabletting process in real time. Direct compression tablet formulations comprising micronized chlorpheniramine maleate, lactose, microcrystalline cellulose and magnesium stearate were used. A custom built NIR setup was used for in-line spectral acquisition (980-1900nm with 1nm resolution) during the tabletting process. Calibration models using dynamic spectral acquisition were prepared and validated using design of experiment approach. During tabletting, stratified sampling of tablets was also carried out to compare the NIR prediction results and subsequent UV analysis results for drug content. The results obtained with calibration and validation statistics confirmed the accuracy of models used to predict contents of tablet components. Stratified sampling results for drug content did not exhibit any significant statistical variation. However, in-line quantification enabled the content analysis of individual tablets in the production batch and detection of content uniformity problems towards the end of the tabletting process. Furthermore, it provided the assurance of in-process content uniformity monitoring of the individual excipients during the tabletting process.

The objective of this study was to illustrate the sampling paradox resulting from the different strategies of spectral acquisition while preparing and implementing the calibration models for prediction of blend components in multi-component cohesive blends. A D-optimal mixture design was used to create 24 blending runs of the formulation consisting of chlorpheniramine maleate, lactose, microcrystalline cellulose and magnesium stearate. Three strategies:(a) laboratory mixing and static spectral acquisition,(b) IBC mixing and static spectral acquisition and (c) IBC mixing and dynamic spectral acquisition were investigated for obtaining the most relevant and representative calibration samples. An optical head comprising a sapphire window mounted on the lid of the IBC was used for static and dynamic NIR spectral acquisition of the powder blends. For laboratory mixed samples, powders were blended for fixed period of 30 min and later on scanned for NIR spectra. For IBC mixed blends, the spectral acquisition was carried out in-line for 2 min and stopped for static spectral acquisition. The same cycle was repeated for the next 28 min. Partial least square (PLS) calibration models for each component were built and ranked according to their calibration statistics. Optimal calibration models were selected from each strategy for each component and used for in-line prediction of blend components of three independent test runs. Although excellent statistics were obtained for the PLS models from the three strategies, significant discrepancies were observed during prediction of the independent blends in real time. Models built using IBC mixed blends and dynamic spectral acquisition resulted in the most accurate predictions for all the blend components, whereas models prepared using static spectral acquisition (laboratory mixed and IBC) showed erroneous prediction results. The prediction performance differences between the models obtained using the different strategies could be explained in the context of relevancy and representative sample collection at the initial stage of calibration model building.

The application of chemical-modified gold nanoparticles (GNPs) as chiral selector for the enantioseparation based on pseudostationary phase-CEC (PSP-CEC) is presented. GNPs modified by thiolated beta-CD were characterized by NMR and FT-IR. The nanoparticle size was determined to be of 9.5 nm (+2.5 nm) by Transmission Electron Microscopy (TEM) and UV spectra. Four pairs of dinitrophenyl-labeled amino acid enantiomers (DL-Val, Leu, Glu and Asp) and three pairs of drug enantiomers (RS-chlorpheniramine, zopiclone and carvedilol) were analyzed by using modified GNPs as the chiral selector in PSP-CEC. Good theoretical plate number (up to 2.4x10(5) per meter) and separation resolution (up to 4.7) were obtained even with low concentration of modified GNPs (0.8-1.4 mg/mL). The corresponding concentration of beta-CD in the buffer was only 0.30-0.53 mM, which was much lower than the optimum concentration of 15 mM if pure beta-CD was used as chiral selector. Our results showed that thiolated beta-CD modified GNPs have more sufficient interaction with the analytes, resulting in significant enhancement of enantioseparation. The study shed light on potential usage of chemical modified GNPs as chiral selector for enantioseparation based on PSP-CEC.

This study investigated the inclusion complexes of beta-cyclodextrin with pheniramine and its halogenated derivatives chlorpheniramine and brompheniramine both experimentally and theoretically to characterize the effects of a halogenated phenyl ring on the intermolecular interactions. Fourier transform infrared and nuclear magnetic resonance (NMR) experiments provided evidence of the formation of inclusion complexes and NMR were conducted to evaluate the apparent binding constants. The two-layered hybrid ONIOM method, ONIOM(B3LYP/6-31G(d):PM3), was adopted to optimize the geometry. The linear relationships between the calculated and experimental values for frequencies (with a scaling factor of 0.96) and for magnetic properties (with a scaling factor of 1.05) demonstrate that the quantum chemical calculations were consistent with the experimental spectra. Additionally, the calculated binding energies were consistent with the experimental results: the stability order of the complexes and the trend of the binding energy is: brompheniramine>chlorpheniramine>pheniramine; S-enantiomer>R-enantiomer. Natural Bond Orbital analysis further demonstrated three major electronic delocalizations--from the substituent on the phenyl moiety of pheniramine to beta-CD and from beta-CD to the phenyl and amine moieties in pheniramine--which were the dominant intermolecular forces that were responsible for the substantially different binding strengths. Geometrical data and the partial charge distribution obtained by NBO analysis are provided as supplementary data.

The differently sulfonated styrene-divinylbenzene cross-linked copolymer cationic exchange resins were prepared by oil-in-water polymerization and varied degrees of sulfonation. Several characteristics of the obtained resins were evaluated, i.e., Fourier transform infrared spectra, the ion-exchange capacity, microscopic morphology, size, and swelling. The resin characteristics were altered in relation to the degree of sulfonation, proving that differently sulfonated resins could be prepared. The behavior of chlorpheniramine (CPM) loading and in vitro release in the USP simulated gastric (SGF) and intestinal fluids (SIF) of the obtained resins were also evaluated. The CPM loaded in the resinates (drug-loaded resins) increased with the increasing degree of sulfonic group and hence the drug binding site in the employed resins. The CPM release was lower from the resins with the higher degree of sulfonic group due to the increase in the diffusive path depth. The CPM release was obviously lower in SGF than SIF because CPM, a weak base drug, ionized to a greater extent in SGF and then preferred binding with rather than releasing from the resins. In conclusion, the differently sulfonated resins could be utilized as novel carriers for drug delivery.

Using an achiral ionic liquid, 1-butyl-3-methylimidazolium chlorine ([ BMIM] Cl), as an additive and beta-cyclodextrin (beta-CD) as a chiral selector, the enantiomers of chlorpheniramine, the precursor of chloramphenicol and of loxacin were separated by capillary zone electrophoresis. This work was directed to the study of the association of [BMIM] Cl to the chiral selector beta-CD and the possible effects of [BMIM] Cl on chiral separation. Simultaneously, the separation performances were studied when only containing beta-CD in the buffer. The results showed that there are synergistic effects of [BMIM] Cl as an additive for the enantiomeric separations.[BMIM] Cl can not only remarkably increase the separation selectivity and resolution of the enantiomers, but also effectively restrain the adsorption of the sample molecules and improve the peak shape.[BMIM] Cl as an additive of chiral separation can provide a new method for the separation of chiral drugs which are hard separable under common electrophoresis conditions.

A computational approach was proposed to study monomer-template interactions in a molecularly imprinted polymer (MIP) in order to gain insight at the molecular level into imprinting polymer selectivity, regarding complex formation between template and monomer at the pre-polymerisation step. This is the most important step in MIP preparation. In the present work, chlorphenamine (CPA), diphenhydramine (DHA) and methacrylic acid (MAA), were chosen as the template, non-template, and monomer, respectively. The attained complexes were optimised, and changes in the interaction energies, atomic charges, IR spectroscopy results, dipole moment, and polarisability were studied. The effects of solvent on template-monomer interactions were also investigated. According to a survey of the literature, this is the first work in which dipole moment and polarisability were used to predict the types of interactions existing in pre-polymerisation complexes. In addition, the density functional tight-binding (DFTB) method, an approximate version of the density functional theory (DFT) method that was extended to cover the London dispersion energy, was used to calculate the interaction energy.

A sequential injection (SI) method was developed for the determination of chlorpheniramine (CPA), based on the reaction of this drug with tris(1,10-phenanthroline)-ruthenium(II)[Ru(phen)(3)(2+)] and peroxydisulphate (S(2)O(8)(2-)) in the presence of light. The instrumental set-up utilized a syringe pump and a multiposition valve to aspirate the reagents [Ru(phen)(3)(2+) and S(2)O(8)(2-)] and a peristaltic pump to propel the sample. The experimental conditions affecting the chemiluminescence reaction were systematically optimized, using the univariate approach. Under the optimum conditions linear calibration curves of 0.1-10 microg/ml were obtained. The detection limit was 0.04 microg/ml and the relative standard deviation (RSD) was always < 5%. The procedure was applied to the analysis of CPA in pharmaceutical products and was found to be free from interferences from concomitants usually present in these preparations.

This article describes buccal permeation of chlorpheniramine maleate (CPM) and its transbuccal delivery using mucoadhesive buccal patches. Permeation of CPM was calculated in vitro using porcine buccal membrane and in vivo in healthy humans. Buccal formulations were developed with hydroxyethylcellulose (HEC) and evaluated for in vitro release, moisture absorption, mechanical properties, and bioadhesion, and optimized formulation was subjected for bioavailability studies in healthy human volunteers. In vitro flux of CPM was calculated to be 0.14 +/- 0.03 mg.h(-1).cm(-2) and buccal absorption also was demonstrated in vivo in human volunteers. In vitro drug release and moisture absorbed were governed by HEC content and formulations exhibited good tensile and mucoadhesive properties. Bioavailability from optimized buccal patch was 1.46 times higher than the oral dosage form and the results showed statistically significant difference.

Lamination of alginate matrix tablet at acidic pH can compromise its function as a sustained release carrier. This phenomenon is associated with the conversion of sodium alginate to alginic acid. An innovative approach for controlling the release of a highly water-soluble drug from such matrices is presented in this paper. Inclusion of pH-modifiers was employed to raise the micro-environmental pH within matrices undergoing dissolution at gastric pH. The changes in micro-environmental pH of hydrating alginate matrices were visualized with the aid of a pH-indicator and subsequently quantified using image analysis. Transient elevation in micro-environmental pH impeded alginate protonation and minimized or prevented matrix lamination, contributing to preservation of drug diffusion barrier. Significant reduction in the rate of drug release at pH 1.2 was achieved in the presence of such additives. The action of pH-modifiers was synergistically enhanced in the presence of a carbon dioxide barrier formed by effervescing sodium bicarbonate, reducing drug release in the acidic medium from 60 to 20%. Further insight into the influence of lamination on drug release from alginate compacts was given.

The aim of this research is to investigate the effects of sodium lauryl sulfate (SLS) on ionotropically cross-linked alginate beads. Different levels of SLS were mixed with sodium alginate and chlorpheniramine maleate (as loaded model drug). The resulting viscous solutions were dropped onto aqueous solutions of zinc or calcium ions for ionotropic curing. The generated beads were assessed by their drug releasing profiles, infrared and differential scanning colorimetery (DSC) traits. SLS was found to exert profound concentration-dependent impacts on the characteristics of zinc-crosslinked alginate beads such that moderate modifications in the levels of SLS switched drug release from enteric coating-like behavior to a biphasic release modifiable to sustained-release by the addition of minute amounts of xanthan gum. Calcium cross-linking failed to reproduce the same behavior, probably due to the mainly ionic nature of calcium-carboxylate bonds compared to the coordinate character of their zinc-carboxylate counterparts. Apparently, moderate levels of SLS repel water penetration into the beads, and therefore minimize chlorpheniramine release. However, higher SLS levels seem to discourage polymeric cross-linking and therefore allow biphasic drug release.

The present study aims to investigate the behavior of melt agglomeration with a low-viscosity hydrophobic meltable binder by using a non-meltable additive. The size, crushing strength, and pore size distribution of resultant agglomerates, the rheological, surface tension, and wetting properties of the molten binder, as well as, the flow characteristics of preagglomeration powder blend were determined. The use of additive showed contradictory agglomerate growth-promoting and -retarding effects on the molten binder surface tension and the interparticulate frictional forces. Critical concentration effects of additive corresponded to threshold transition of agglomeration-promoting to -retarding behavior were discussed.

Uniformly sized molecularly imprinted polymers (MIPs) for d-chlorpheniramine have been prepared by a multi-step swelling and polymerization method using methacrylic acid (MAA) or 2-(trifluoromethyl)acrylic acid (TFMAA) as a functional monomer and toluene, phenylacetonitrile, benzylacetonitrile or chloroform as a porogen. From measurement of their scanning electron microscopy images and physical properties in the dry state, the MIP prepared using TFMAA and chloroform as the functional monomer and porogen, respectively, seemed to be non-porous and had extremely low specific surface areas and pore volumes, while the other MIPs were porous beads with high specific surface areas and pore volumes. All the MIPs prepared were evaluated using hydro-organic mobile phases in HPLC. As a result, they showed the similar retentive and enantioselective properties for chlorpheniramine, brompheniramine and pheniramine. This result suggests the presence of enantioselective binding sites in the swollen state for all the MIPs.