Concurrent chromatographic determination of pseudoephedrine and loratadine from combination syrups and tablets

Background Chromatographic separation of polar and nonpolar compounds when presented in combined dosage forms has always been considered as great analytical challenge. Separation and retention of both polar and nonpolar compounds by the same stationary phase can be a useful approach for analyses of complex samples with such a difference in chemical properties. Loratadine (nonpolar) and pseudoephedrine (polar) are typical examples of this situation. Results The Box–Behnken design was used to optimize the separation process, an efficient separation of loratadine and pseudoephedrine was achieved within 6 min; employing a mixture of 16.0 mM ammonium acetate buffer (pH 4.5) and acetonitrile (23:77, v/v) as isocratic mobile phase, pumped at 1.0 mL/min through a Zorbax cyanopropyl column (250 mm × 4.6 mm, 5 μm), the analytes were detected at 250 nm. Under the same conditions, separation of sodium benzoate preservative co-formulated with the two analytes in syrup formulation was also achieved. The calibration curve demonstrated excellent linearity in the range of 24.6–123.2 μg/mL and 594.8–2974.0 μg/mL for loratadine and pseudoephedrine, respectively with determination coefficient (r2) > 0.999. Conclusion The method’s accuracy bias < 2.0%, repeatability and intermediate precision (%RSD < 2.0%) were verified. In addition, system suitability parameters were found within the acceptable limits. Satisfactory results were obtained upon the application of the validated method to the analysis of commercial tablet and syrup formulations.

Detection of an IL-6 Biomarker Using a GFET Platform Developed with a Facile Organic Solvent-Free Aptamer Immobilization Approach

Aptamer-immobilized graphene field-effect transistors (GFETs) have become a well-known detection platform in the field of biosensing with various biomarkers such as proteins, bacteria, virus, as well as chemicals. A conventional aptamer immobilization technique on graphene involves a two-step crosslinking process. In the first step, a pyrene derivative is anchored onto the surface of graphene and, in the second step, an amine-terminated aptamer is crosslinked to the pyrene backbone with EDC/NHS (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide) chemistry. However, this process often requires the use of organic solvents such as dimethyl formamide (DMF) or dimethyl sulfoxide (DMSO) which are typically polar aprotic solvents and hence dissolves both polar and nonpolar compounds. The use of such solvents can be especially problematic in the fabrication of lab-on-a-chip or point-of-care diagnostic platforms as they can attack vulnerable materials such as polymers, passivation layers and microfluidic tubing leading to device damage and fluid leakage. To remedy such challenges, in this work, we demonstrate the use of pyrene-tagged DNA aptamers (PTDA) for performing a one-step aptamer immobilization technique to implement a GFET-based biosensor for the detection of Interleukin-6 (IL-6) protein biomarker. In this approach, the aptamer terminal is pre-tagged with a pyrene group which becomes soluble in aqueous solution. This obviates the need for using organic solvents, thereby enhancing the device integrity. In addition, an external electric field is applied during the functionalization step to increase the efficiency of aptamer immobilization and hence improved coverage and density. The results from this work could potentially open up new avenues for the use of GFET-based BioMEMS platforms by broadening the choice of materials used for device fabrication and integration.

Ethyl Acetate and Aqueous Fractions of Ziziphus jujuba Prevent Acute Hypertension Induced by Angiotensin II in Rats

Background: The effect of hydroalcoholic extract of Ziziphus jujuba (ZJ) on hypertension has been reported previously. Objective: This experiment investigates the effect of two ethyl acetate (EA, a polar and semi-polar compound) and aqueous fractions (AQ, a polar compound) of ZJ extract on cardiovascular parameters in acute hypertension induced by angiotensin II (AngII). Methods: Rats were randomly divided into following groups (n=7 in each group): 1) Control; 2) AngII (50 ng/kg); 3) Losartan (LOS, 30 mg/kg) + AngII; 4, 5) ethyl acetate fraction (EA150 and EA300 mg/kg) + AngII and 6, 7) aqueous fraction (AQ150 and AQ300 mg/kg) + AngII. Rats were treated with both fractions and LOS orally for four weeks and in the experiment day (28th) AngII intravenously injected and cardiovascular parameters (Systolic Blood Pressure (SBP), Mean Arterial Pressure (MAP) and Heart Rate (HR)) directly were recorded by a power lab system. Results: AngII could significantly increase SBP and MAP (P<0.001) and decrease HR with respect to the control and these responses were attenuated by LOS. The SBP and MAP in both doses of EA+ AngII and the higher dose of AQ fractions + AngII were significantly lower than the AngII group (P<0.05 to P<0.001). Bradycardia induced by AngII was also reduced by LOS and both fractions. The comparison of two fractions also showed that the effect of EA fraction is greater than the AQ. Conclusion: This study indicates that both fractions of the ZJ extract have a beneficial effect on hypertension. Because effect of EA was greater than AQ, we suggested that antihypertensive effects of ZJ mediated polar and nonpolar compounds.

Development and Evaluation of Antimicrobial and Modulatory Activity of Inclusion Complex of Euterpe oleracea Mart Oil and β-Cyclodextrin or HP-β-Cyclodextrin

The development of inclusion complexes is used to encapsulate nonpolar compounds and improve their physicochemical characteristics. This study aims to develop complexes made up of Euterpe oleracea Mart oil (EOO) and β-cyclodextrin (β-CD) or hydroxypropyl-β-cyclodextrin (HP-β-CD) by either kneading (KND) or slurry (SL). Complexes were analyzed by molecular modeling, Fourier-transform infrared spectroscopy, scanning electron microscopy, powder X-ray diffraction, thermogravimetry analysis and differential scanning calorimetry. The antibacterial activity was expressed as Minimum Inhibitory Concentration (MIC), and the antibiotic resistance modulatory activity as subinhibitory concentration (MIC/8) against Escherichia coli, Streptomyces aureus, Pseudomonas aeruginosa and Enterococcus faecalis. Inclusion complexes with β-CD and HP-β-CD were confirmed, and efficiency was proven by an interaction energy between oleic acid and β-CD of −41.28 ± 0.57 kJ/mol. MIC values revealed higher antibacterial activity of complexes compared to the isolated oil. The modulatory response of EOO and EOO-β-CD prepared by KND as well as of EOO-β-CD and EOO-HP-β-CD prepared by SL showed a synergistic effect with ampicillin against E. coli, whereas it was not significant with the other drugs tested, maintaining the biological response of antibiotics. The antimicrobial response exhibited by the complexes is of great significance because it subsidizes studies for the development of new pharmaceutical forms.

Detection of terpenes of Iraqi Artemisia abrotanum L. by GC/MS in hexane extract

Artemisia abrotanum L. is recently introduced plant in Iraq, in this study we conducted GS/MS for detection of terpene that are group of constituents abundant in this species qualitatively and quantatively. We used hexane extract for the detection depending on the like dissolve like proce- dure of extraction since they are mostly nonpolar compounds, they dissolve in nonpolar solvent like hexane thus the extraction procedure is conducted with this solvent. New compound was detected with hexane extract that wasn't present in previous studies.

Variation in Chemical Composition of Cuticular and Nonpolar Compounds of Venom of Apoica pallens and Polistes versicolor

Although cuticular hydrocarbons and venom are important to the evolutionary success of social behavior, studies that investigated these compounds in tropical social wasps are rare. Thus, the aim of this study was to compare the cuticular chemical composition and the nonpolar portion of venom of Apoica pallens, a swarm-founding wasp and Polistes versicolor an independent-founding wasp. Gas chromatography coupled to mass spectrometry (GC/MS) technique was used. In the samples of A. pallens, 66 compounds were identified on the cuticle and 87 in venom, 13 are unique of the cuticle and 26 of venom. In the samples of P. versicolor, 85 compounds were identified on the cuticle and 60 in venom, 10 are exclusive of the cuticle and 5 of venom. The results show that, although they present different foundation types and organize in colonies with significantly different population number, the variation in chain length of compounds is relatively similar. In addition, in both types of samples of both species, the most representative class of compounds in content and number are the branched alkanes, which are recognized as the most effective during interactions between nestmates. However, there is greater similarity in content of shared compounds between samples of cuticle and venom of A. pallens, suggesting that because it is a species that is organized in more populous colonies, it may have a more elaborate signaling system based on volatile compounds of venom.