Antimicrobial gelatin-based films with cinnamaldehyde and ZnO nanoparticles for sustainable food packaging.

Cinnamaldehyde (CIN), a harmless bioactive chemical, is used in bio-based packaging films for its antibacterial and antioxidant properties. However, high amounts can change food flavor and odor. Thus, ZnO nanoparticles (NPs) as a supplementary antimicrobial agent are added to gelatin film with CIN. The CIN/ZnO interactions are the main topic of this investigation. FTIR-Attenuated Total Reflection (ATR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were utilized to investigate CIN/ZnO@gelatin films. Transmission electron microscope (TEM) images revealed nanospheres morphology of ZnO NPs, with particle sizes ranging from 12 to 22 nm. ZnO NPs integration increased the overall activation energy of CIN/ZnO@gelatin by 11.94%. The incorporation of ZnO NPs into the CIN@gelatin film significantly reduced water vapour permeability (WVP) of the CIN/ZnO@gelatin film by 12.07% and the oxygen permeability (OP) by 86.86%. The water sorption isotherms of CIN/ZnO@gelatin were described using Guggenheim-Anderson-de Boer (GAB) model. The incorporation of ZnO NPs into the CIN@gelatin film reduced monolayer moisture content (M0) by 35.79% and significantly decreased the solubility of CIN/ZnO@gelatin by 15.15%. The inclusion of ZnO into CIN@gelatin film significantly decreased tensile strength of CIN/ZnO@gelatin by 13.32% and Young`s modulus by 18.33% and enhanced elongation at break by 11.27%. The incorporation of ZnO NPs into the CIN@gelatin film caused a significant decrease of antioxidant activity of CIN/ZnO@gelatin film by 9.09%. The most susceptible organisms to the CIN/ZnO@gelatin film included Candida albicans, Helicobacter pylori, and Micrococcus leutus. The inhibition zone produced by the CIN/ZnO@gelatin film versus Micrococcus leutus was 25.0 mm, which was comparable to the inhibition zone created by antibacterial gentamicin (23.33 mm) and cell viability assessment revealed that ZnO/CIN@gelatin (96.8 ± 0.1%) showed great performance as potent biocompatible active packaging material.

Potential antimicrobial cotton fabrics treated with cinnamaldehyde/chitosan-alginate nanocapsules for food packaging purposes.

In this study, cotton fabric was treated with chitosan/alginate nanocapsules containing cinnamaldehyde (CINA) as a natural antibacterial and antioxidant. Cinnamaldehyde was encapsulated into chitosan/alginate complex coacervate (CINA@CH/ALG). FTIR, XRD, TEM, and SEM were utilized to investigate the formation of CINA@CH/ALG nanocapsules. The weight ratios of chitosan, alginate, and the volume fractions of cinnamaldehyde have a considerable impact on the particle size of the CINA@CH/ALG nanocapsules but no significant effect on the zeta potential. The lowest particle size was 549.8 nm at a weight ratio of 1/1 and 712.6 nm for CH/ALG nanocapsules containing cinnamaldehyde oil fractions of 0.025 mL. The maximum encapsulation (91.4 %) and loading percentage (12.0 %) were achieved with 0.025 mL of cinnamaldehyde. The highest cumulative release was 50.76 % with 0.025 mL of cinnamaldehyde over 300 min. The releasing mechanism of CINA from CINA(0.025)@CH/AG follows the bi-exponential model. The maximum radical scavenging activity was 72.91 % with 0.1 mL of CINA. CINA@CH/ALG nanocapsules were applied to cotton fabric. All tested pathogen strains were sensitive to CINA@CH/ALG, with a CINA volume fraction of 0.025 representing the minimum inhibitory concentration (MIC). Salmonella Typhimurium is the pathogen most prone to cinnamaldehyde with an inhibition zone of 18 mm. The coating of cotton fabric with CINA@CH/ALG has implanted antibacterial and antifungal properties.

Fabrication of multifunctional ZnO@tannic acid nanoparticles embedded in chitosan and polyvinyl alcohol blend packaging film.

The current study explores biodegradable packaging materials that have high food quality assurance, as food deterioration is mostly caused by UV degradation and oxidation, which can result in bad flavor and nutrition shortages. Thus, new multifunctional zinc oxide nanoparticles/tannic acid (ZnO@TA) with antioxidant and antibacterial activities were incorporated into polyvinyl alcohol/chitosan (PVA/CH) composite films with different ratios (1%, 3%, and 5% based on the total dry weight of the film) via a solution blending method in a neutral aqueous solution. Additionally, ZnO nanoparticles have unique antibacterial mechanisms through the generation of excessive reactive oxygen species (ROS) that may lead to intensify pathogen resistance to conventional antibacterial agents. Thus, minimizing the negative effects caused by excessive levels of ROS may be possible by developing unique, multifunctional ZnO nanoparticles with antioxidant potential via coordination bond between tannic acid and ZnO nanoparticles (ZnO@TA). ZnO@TA nanoparticles were examined using Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The effect of the incorporation of ZnO@TA nanoparticles on the barrier, mechanical, thermal, antioxidant, antimicrobial, and UV blocking characteristics of chitosan/polyvinyl alcohol (ZnO@TA@CH/PVA) films was investigated. The lowest water vapor and oxygen permeability and the maximum antioxidant capacity% are 31.98 ± 1.68 g mm/m2 kPa day, 0.144 ± 5.03 × 10-2 c.c/m2.day, and 69.35 ± 1.6%, respectively, which are related to ZnO@TA(50)@CH/PVA. Furthermore, ZnO@TA(50)@CH/PVA film exhibits the maximum UV shielding capacity of UVB (99.994). ZnO@TA(50) @PVA/CH films displayed better tensile strength and Young`s modulus of 48.72 ± 0.23 MPa and 2163.46 ± 61.4 MPa, respectively, than the other film formulations. However, elongation % at break exhibited the most reduced value of 19.62 ± 2.3%. ZnO@TA@CH/PVA film exhibits the largest inhibition zones of 11 ± 1.0, 12.3 ± 0.57, and 13.6 ± 0.57 mm against Staphylococcus aureus, Aspergillus flavus, and Candida albicans, respectively. In accordance with these results, ZnO@TA@CH/PVA films could be utilized for food preservation for the long-term.

Sustained-release nitrogen fertilizer delivery systems based on carboxymethyl cellulose-grafted polyacrylamide: Swelling and release kinetics.

Sustained or controlled-release delivery systems can enhance functions such as nutrient usage; minimize soil contamination, and reduce the required fertilizer dose. This paper reports the development of a carboxymethyl cellulose-g-polyacrylamide copolymer (CMC-g-PAM) as a sustained and slow-release fertilizer carrier for urea. The developed copolymer was characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and thermo gravimetric analysis (TG). The grafting process increased the activation energy of CMC from 0.1521 to 0.5952 J/mol with a higher loading percentage of 72.140.85% using a 15% urea solution. The swelling ratio is significantly dependent on the pH. The maximum swelling ratio of 1199.58% at pH 9. However, Swelling follows a pseudo-first-order reaction with the maximum swelling ratio in a saline of 349.76%. The CMC-g-PAM copolymer loaded with urea exhibited sustained and slow release, with the maximum cumulative percentage of 69.12% at pH 9 and 38.94% in saline. Urea release from the CMC-g-PAM copolymer followed the first-order, Fickian, and biexponential biphasic release mechanisms. The release of the CMC-g-PAM copolymer loaded with urea is a complicated process governed by diffusion and a biphasic releasing profile.

Dialdehyde cellulose/gelatin hydrogel as a packaging material for manganese oxides adsorbents for wastewater remediation: Characterization and performance evaluation.

The dialdehyde cellulose (DC) was used to synthesize gelatin-cellulose dialdehyde by Schiff base as a packaging material to manganese oxides nanoparticles adsorbents (Mn oxides@DC/Gel) for wastewater remediation and support the antimicrobial behavior of gelatin and DC. The crystallinity index% of microwave-synthesized DC prepared from cellulose II decreased from 43.18% to 34.11% and its oxidation degree was 143.77%. The greenly-produced Mn oxides were studied by XRD and TEM. XRD verified the presence of two different phases of α-MnO2 and α-Mn2O3 in the form of nanorods and nanocubes. Mn oxides@DC/Gel was investigated by FT-IR, XRD, XPS, SEM, swelling absorptivity, and thermal analysis. The optimal swelling ratio% of Mn oxides@DC/Gel nanocomposite was 1494.04±16.65%. The influence of pH on swelling ratios verified the instability of the imine group in acid and basic media. Mn oxides@DC/Gel nanocomposite hydrogel causes approximately two-fold greater inhibitory zones than gentamicin. The optimal adsorption conditions were adsorbent dose (0.05g), pH (9.0), contact time (120 min), and methylene blue dye concentration (30mg/L). The maximum adsorption capacity of Mn oxides@DC/Gel nanocomposite was 51.06±1.0 mg/g. The adsorption by Mn oxides@DC/Gel nanocomposite agrees with Langmuir, Redlich-Peterson, and Freundlich mechanisms.

Fabrication and evaluation of antimicrobial cellulose/Arabic gum hydrogels as potential drug delivery vehicle.

This article aims to assess the highly potent antimicrobial hydrogels composed of cellulose and Arabic gum containing sulfadiazine drug (sulfadiazine-loaded Cel/AG) as drug-targeting carriers. ATR-IR, SEM/ EDS, XRD, and XPS methods were used to investigate the hydrogel. The highest water absorption % was 489.93 ± 4.5 at pH 7.4. Pseudo-second order and Fickian diffusion govern the swelling behavior. The maximal sulfadiazine loading percent was 82.291 ± 74. The in-vitro drug release exhibited significant responses in physiologically simulated pH values. The maximum cumulative release percent was 66.42 ± 0.6 % at pH 7.4. The drug release is predicted by the first order and Korsmeyer-Peppas models. The first diffusion coefficient was (Di = 9.207 ± 47 × 10-3 cm2/h) and the late one was (DL = 5.64 ± 9.0 × 10-2 cm2/h) at pH 7.4. That hydrogel is well-thought-out a potential drug delivery vehicle. The thermal stability of the Cel/AG hydrogel drug carrier has been enhanced by the incorporation of sulfadiazine which is evidenced by increasing the total activation approximately two-fold. The total activation energy of Cel/AG and sulfadiazine-loaded Cel/AG hydrogels were -0.07362 and -0.2092 J/mol. The sulfadiazine medication's inhibitory effect was markedly enhanced when it was incorporated into the Cel/AG hydrogel films.

Sensitive and effective electrochemical determination of butenafine in the presence of itraconazole using titanium nanoparticles-ionic liquid based nanocomposite sensor.

The evaluation of the bioavailability of topically applied medications that act inside or under the skin is a challenging task. Herein, the current study describes a simple, quick, and low-cost electrochemical platform for determining butenafine hydrochloride (BTH) that is mainly prescribed as a treatment of dermatophytosis, applying titanium nanoparticles and an ionic liquid as outstanding mediators. In terms of low detection limits (61.63 nM) and extensive range of 2.21 × 10-7-13.46 × 10-5 M, the established electrochemical technique provided worthy analytical performance for butenafine hydrochloride sensing. The suggested sensor's practical applicability was effectively demonstrated in pharmaceutical preparations, actual stratum corneum samples, and simultaneous detection of butenafine hydrochloride and Itraconazole in pharmaceutical preparation for the first time. All of the experimental factors, like the pH and scan rate, have been investigated and optimized. Diffusion coefficients of butenafine hydrochloride at bare and modified sensors were calculated. Supplementary Information: The online version contains supplementary material available at 10.1007/s11696-022-02593-3.

Quality assessment of lemon (Citrus aurantifolia, swingle) coated with self-healed multilayer films based on chitosan/carboxymethyl cellulose under cold storage conditions.

The polyelectrolyte multilayer self-healing coating film of chitosan and carboxymethyl cellulose (PEM-SH) tended to maintain high sensory quality and control physiological and pathological decay of lemon fruits under cold storage. The PEM-SH film was characterized by ATR-IR, XRD, X-ray photoelectron spectroscopy, SEM analysis, swelling ratio, self-healing, and mechanical characteristics. The 3-layered film (3L) exhibited the optimum barrier properties; WVP: 3.32 ± 0.06 g. mm. k Pa-1.h-1.m-2 and GTR: 0.256 ± 0.032 cc.M-2.day-1. The moisture sorption isotherm data were fitted with BET, GAB, and Peleg models and three models showed applicability. The coated fruits exhibit superior features of fruit quality such as reduced weight loss %, respiration rate, and decay symptoms appearance. The 3L-coated fruit showed the lower pectinase enzyme activity (0.689 Ug-1 FW) up to 60 days. As well as, increased total soluble solids, keeping vitamin C of loss and decreasing percentage acidity of juice up to 60 days.

Physically-crosslinked hydroxyethyl cellulose-g-poly (acrylic acid-co-acrylamide)-Fe3+/silver nanoparticles for water disinfection and enhanced adsorption of basic methylene blue dye.

In this study, we report the development of physically cross-linked hydroxyethyl cellulose grafted polyacrylic acid-co-polyacrylamide/silver nanocomposite [Ag@HEC-g-P(AA-co-AM)-Fe3+] possesses excellent antimicrobial and enhanced MB adsorption. A green in-situ reduction process was used to prepare silver nanoparticles. UV-Vis spectroscopy, TEM, ATR-IR, XRD, SEM-EDS were used to analyze the green produced silver nanoparticles and Ag@HEC-g-P(AA-co-AM)-Fe3+. The swelling ratio of Ag@HEC-g-P(AA-co-AM)-Fe3+ is dependent on AgNPs content and pH. The swelling kinetics fitted with Pseudo-second order. The cumulative release#% of AgNPs was 29.63 ± 1.7%, respectively up to 10 h and its kinetics obey Korsmeyer-Peppas model. The grafting to HEC and incorporation of AgNPs into HEC-g-P(AA-co-AM)-Fe3+ enhances the thermal stabilities and increases total activation energies from 19,122.2 to 66,287.1 KJ mol. Ag@HEC-g-P(AA-co-AM)-Fe3+ has powerful antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Micrococcus leutus, Staphyllococus aureus. The maximum adsorption capacity of MB was 133.38 ± 1.25 mg/g at nanocomposite concentration (300 mg/L), pH (9.0), and MB concentration (5 mg/L). To anticipate the adsorption mechanism, Pseudo-first and second-order models, as well as three isotherm models (Langmuir, Freundlich, and Temkin) were used to model adsorption kinetics. The nonlinear Langmuir models and second-order kinetics were the most appropriate.

Development of Arabic gum-based AgTiO2 nanocomposite hydrogel as high efficient adsorbent of cationic dye methylene blue from water.

The chemically crosslinked silver titanium dioxide embedded Arabic gum grafted polyacrylamide-polyacrylonitrile nanocomposite AgTiO2@AG-g-P(AM-co-AN)was successfully synthesized and investigated by ATR-IR, XRD, and SEM. The synthesis optimization parameters of AG-g-P(AM-co-AN)were 5% AG, 1/0.5 AM/AN monomer molar ratio, 0.5 mg MBA cross-linker, and AgTiO2 content (1%) gives AgTiO2@AG-g-P(AM-co-AN) nanocomposite. While adsorption studies for AgTiO2@AG-g-P(AM-co-AN) exhabited the maximum adsorption capacity (104.50 ± 3.02 mg/g) at concentration (150 mg/L), MB concentration (15 mg/L) and pH (8.0). The adsorption nonlinear kinetics models were used. Pseudo-second order governs the adsorption process, and the Langmuir model is more suited than Freundlich and Temkin.

Simultaneous determination of dantrolene and paracetamol in human plasma by liquid chromatography tandem mass spectrometry.

A simple, sensitive, rapid and specific method based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the simultaneous quantification of dantrolene (DAN) and paracetamol (PAR) in real human plasma was developed and validated. The preparation of sample was achieved by liquid-liquid extraction with tertiary butyl methyl ether. The analysis was performed on a reversed-phase C18column (1.7 µm, 2.1 × 30 mm) using acetonitrile: 0.1% formic acid (80:20, v/v) as the mobile phase and pumped in an isocratic mode at a flow rate of 0.3 mL/min using citalopram (CIT) as an internal standard. Tandem mass spectrometric detection was carried out by both positive and negative electrospray ionization (ESI) in the multiple-reaction monitoring mode (MRM). The analysis was carried out within 1 min for each sample which made it possible to analyze more than 350 human samples per day. Validation of the method was performed according to FDA guidelines for bio-analytical method. The method was found to be linear in the range of 25-2500 ng/mL and 100-10,000 ng/mL for DAN and PAR, respectively. The method was applied successfully for the determination of the two analytes in the plasma after oral administration of Dantrelax® compound capsules to healthy volunteers. The study was accomplished after approval of the ethics committee.

Smart edible coating films based on chitosan and beeswax-pollen grains for the postharvest preservation of Le Conte pear.

Smart edible coating films can be used in food packaging. For this application, they must have good physical and mechanical properties. Herein, chitosan-beeswax based film is used to preserve Le Conte pears postharvest. The chitosan-beeswax films were characterized using XRD, FT-IR, and SEM analysis. Moreover, all films showed good self-healing aptitudes ranging from 86.7 to 96.3. The film treated with pollen grains showed an enhanced water contact angle compared with the chitosan film. The chitosan-beeswax/pollen grain film exhibited a two-fold lower WVTR value compared to the chitosan film, and showed the tendency to increase the stiffness of the film. The elongation% at break was reduced from 35.81 to 14.09. Fruit quality parameters were determined in cold storage for 105 days during shelf life after a simulated marketing period of 7 days. All coated fruits successfully showed decrease in weight loss, decay and rate of softening. Therefore, chitosan-beeswax/pollen grains can be considered safe and effective coating for the fruit preservation.

Novel Application of Pentabromobenzyl Column for Simultaneous Determination of Eight Antifungal Drugs Using High-performance Liquid Chromatography.

AIM: A new, accurate and sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) as an analytical method for the quantitative determination of eight antifungal drugs in spiked human plasma has been described optimized and validated. MATERIALS AND METHODS: The analyzed compounds were voriconazole (VOR), luliconazole (LUL), clotrimazole (CLO), tioconazole (TIO), posaconazole (POS), ketoconazole (KET), sertaconazole (SER) and terconazole (TER). RESULTS: The separation of the analyzed compounds was conducted using a novel pentabromobenzyl column known as COSMOSIL PBB-R (150 mm × 4.6 mm I.D., particle size 5 µm). The analysis of the studied drugs was determined within 14 min using a diode array detector and the mobile phase consisted of: 10 mM potassium dihydrogen phosphate buffer (pH 2.1): Methanol (2: 98 v/v). A linear response was observed for all compounds in the range of concentration studied. Sample preparation was done through liquid-liquid extraction using diethyl ether. CONCLUSION: This proposed method was validated in terms of linearity, limit of quantification, limit of detection, accuracy, precision and selectivity. The method was successfully applied for the determination of these drugs in their pharmaceutical formulations and in human plasma samples.

Detection and quantification of warfarin in pharmaceutical dosage form and in spiked human plasma using surface enhanced Raman scattering.

Analytical approaches for the quantitation of warfarin in plasma are high in demand. In this study, a novel surface enhanced Raman scattering (SERS) technique for the quantification of the widely used anticoagulant warfarin sodium in pharmaceutical dosage form and in spiked human plasma was developed. The colloidal-based SERS measurements were carefully optimized considering the laser wavelength, the type of metal nanoparticles, their surface functionalization and concentration as well as the time required for warfarin to associate with the metal surface. Poly(diallyldimethylammonium chloride) coated silver nanoparticles (PDDA-AgNPs) were established as a substrate which greatly enhanced the weak warfarin Raman signal with high reproducibility. The limit of detection was calculated in both water and human plasma to be 0.56 nM (0.17 ngmL-1) and 0.25 nM (0.08 ngmL-1) respectively, with a high degree of accuracy and reproducibility. The proposed method is simple, economical, and easily applied for routine application requiring only small plasma samples and also could be potentially useful for pharmacokinetic research on warfarin.

Development and validation of liquid chromatography-electrospray-tandem mass spectrometry method for determination of flibanserin in human plasma: Application to pharmacokinetic study on healthy female volunteers.

A novel rapid and highly sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) bioanalytical method was established for the analysis of flibanserin in human plasma. Flibanserin d4 was used as internal standard (IS). Flibanserin and the internal standard (IS) were extracted from the plasma using protein precipitation technique with acetonitrile. A Kinetex C18 (2.6 µm, 2.1 × 50 mm) column was used for chromatographic separation and the mobile phase was a mixture of 20 mm ammonium acetate buffer (pH 4.5)-acetonitrile (50:50, v/v) with an isocratic elution mode and a flow rate of 0.3 mL/min. The analysis was performed on a Xefo TQD Waters mass spectrometer in multiple reaction monitoring mode with a positive electrospray ionization interface. The US Food and Drug Administration guidelines were followed during the bio-analytical methods validation regarding linearity, precision, accuracy, carryover, selectivity, dilution integrity and stability. The analysis run time was carried out within 2 min over a wide linear concentration range of 5-1000 ng mL-1 . Finally, the proposed method was successfully used in a pharmacokinetic study that measured flibanserin concentration in healthy, non-pregnant female volunteers after a single 100 mg oral dose of flibanserin.

Stability-indicating micellar enhanced spectro-fluorometric determination of Daclatasvir in its tablet and spiked human plasma.

A fast, simple and sensitive micellar enhanced spectrofluorimetric method is performed for the determination of Daclatasvir dihydrochloride (DAC) in its pharmaceutical dosage form and in spiked human plasma. The fluorescence intensity (FI) was measured at 367 nm after excitation at 300 nm. In aqueous solution, the FI of DAC was greatly enhanced by >110% in the presence of sodium dodecyl sulphate (SDS). The detection method was linear over the range of 12.93 to 161.60 ng/mL, with a limit of detection of 1.75 ng/mL. The proposed method was successfully applied to the determination of DAC in its pharmaceutical dosage form and the mean % recovery of DAC in spiked human plasma was 95.42 ±â€¯2.52. The developed methodology was also extended to stress studies of DAC after exposure to different forced degradation conditions including acidic, alkaline, photolytic, thermal and oxidative environments.

Optimized polydopamine coating and DNA conjugation onto gold nanorods for single nanoparticle bioaffinity measurements.

Gold nanorods (NRs) have attracted a great deal of interest for a variety of biomedical and sensing applications. However, developing robust methods for biofunctionalizing NRs has continued to be challenging, especially for NR-DNA conjugates. This is due to the presence of cetyltrimethylammonium bromide (CTAB), which plays an essential role in controlling the anisotropic particle growth. In this article, we systematically explore the growth of a polydopamine (PDA) layer on a range of NR surfaces, comparing different polyelectrolyte and alkanethiol coatings as well as direct CTAB displacement. This revealed that the PDA layer thickness and growth rate is strongly dependent on the underlying nanorod functionalization chemistry and allowed us to establish a preferred route for the creation of stable, non-aggregated suspensions of PDA-coated NRs. The utility of this platform was then demonstrated by self-assembling packed monolayers of single-stranded DNA on the outer surface. Both the surface attachment and bioactivity of the resulting NR-DNA conjugates was then demonstrated by performing bulk solution and single nanoparticle imaging fluorescence measurements.

Validated stability-indicating capillary electrophoresis method for the separation and determination of a fixed-dose combination of carvedilol and hydrochlorothiazide in tablets.

A novel, fast, sensitive, and specific capillary electrophoresis (CE) technique coupled to a diode array detector has been developed for the separation and simultaneous determination of carvedilol (CRV) and hydrochlorothiazide (HCT) in two combination formulations. The proposed method utilized a fused silica capillary (55 cm x75 microm id) and the background electrolyte solution phosphate buffer (12.5 mM, pH 7.4)-methanol (95+5, v/v). The separation was achieved at 30 kV applied voltage and 24 degree C. Atorvastatin (80 microg/mL) was chosen as the internal standard. The described method was linear over the range of 1-200 and 0.2-150 microg/mL for CRV and HCT, respectively. Intraday and interday RSD (n = 6) was < or =1.4%. The LOD values of CRV and HCT were 0.26 and 0.07 microg/mL, respectively. The validated CE method was successfully applied to the analysis of two commercial tablet dosage forms. Forced degradation studies were performed on bulk samples of the two drugs using thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. Degradation products produced as a result of stress studies did not interfere with the determination of CRV and HCT; the assay could, therefore, be considered stability-indicating.

Analytical study for the charge-transfer complexes of rosuvastatin calcium with π-acceptors.

Studies were carried out to investigate the charge-transfer (CT) reaction of ROS-Ca, as a n-electron donor with various p-acceptors: tetracyanoethylene, p-chloranilic acid, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, 2,3,5,6-tetrabromo-1,4-benzoquinone, 1,3,5-trinitrobenzene, 2,3,5,6-tetrachloro-1,4-benzoquinone, 7,7,8,8-tetracyano-quinodimethane, and 2,4,7-trinitro-9-fluorenone. Different colored CT complexes were obtained. The reaction mechanism and site of interaction were determined by ultraviolet-visible spectrophotometric techniques and computational molecular modeling. The formation of the colored complexes was utilized in the development of simple, rapid and accurate spectrophotometric methods for the determination of ROS-Ca. Under the optimum reaction conditions, linear relationships with good correlation coefficients (0.9984-0.9995) were found between the absorbances and the concentrations of ROS-Ca in the range of 2-200 mg mL⁻¹. The limits of detection ranged from 0.41 to 12.24 mg mL⁻¹. No interference could be observed from the additives commonly present in the tablets or from the drugs that are co-formulated with ROS-Ca in its combined formulations. The methods were successfully applied to the analysis of tablets with good accuracy and precision; the recovery percentages ranged from 99.54-100.46 ± 1.58-1.82%. The results were compared favorably with the reported method. The proposed methods are practical and valuable for routine application in quality control laboratories for determination of ROS-Ca in its bulk form and tablets.

Capillary electrophoretic determination of antimigraine formulations containing caffeine, ergotamine, paracetamol and domperidone or metoclopramide.

A novel, fast, sensitive and specific technique using capillary electrophoresis coupled to a diode array detector has been developed for the separation and simultaneous determination of two antimigraine mixtures in tablet formulation. The two combinations are ergotamine tartrate (ERG), caffeine (CAF) and paracetamol (PAR) with either domperidone (DOM), combination (I) or metoclopramide (MET), combination (II). The proposed method utilized a fused silica capillary (55 cm × 75 µm i.d.) and background electrolyte composed of phosphate buffer (25 mM, pH 9.8). The separation was achieved at 20 KV applied voltage and at 25°C. The described method was linear over the range of 1-80 and 2-100 µg/mL for CAF and MET, respectively, and 1-80 µg/mL for DOM, ERG and PAR. Intra-day and inter-day relative standard deviation (n = 5) was ≤1.10%. The limits of detection of CAF and PAR were 0.20 and 0.10 µg/mL, respectively, and 0.50 µg/mL for MET, DOM and ERG. Other aspects of analytical validation were also evaluated. The proposed method was successfully applied to the analysis of the two combinations in their tablets. Therefore, the proposed method is suitable for the routine control of these ingredients in multicomponent dosage forms.