Concentrations Of Hydrochloride Research Articles

Protein Stability Depends Critically on the Surface Hydrogen-Bonding Network: A Case Study of Bid Protein.

Understanding how proteins retain structural stability is not only of fundamental importance in biophysics but also critical to industrial production of antibodies and vaccines. Protein stability is known to depend mainly on two effects: internal hydrophobicity and H-bonding between the protein surface and solvent. A challenging task is to identify their individual contributions to a protein. Here, we investigate the structural stability of the apoptotic Bid protein in solutions containing various concentrations of guanidinium hydrochloride and urea using a combination of recently developed methods including the QTY (glutamine, threonine, and tyrosine) code and electron spin resonance-based peak-height analysis. We show that when the internal hydrophobicity of Bid is broken down using the QTY code, the surface H-bonding alone is sufficient to retain the structural stability intact. When the surface H-bonding is disrupted, Bid becomes sensitive to the temperature-dependent internal hydrophobicity such that it exhibits a reversible cold unfolding above water's freezing point. Using the combined approach, we show that the free-energy contributions of the two effects can be more reliably obtained. The surface H bonds are more important than the other effect in determining the structural stability of Bid protein.

Micellization, acoustic and thermodynamic study of procaine in aqueous solution at different temperatures

Critical micelle concentrations (CMC) of procaine hydrochloride (PHCl) in aqueous solution has been determined from conductivity (κ), density (ρ) and speed of sound (u) measurements using Williams and Philips methods at the temperature range 298.15–318.15 K intervals of 5 K.The CMC values found by these two methods using the speed of sound, density and conductivity data were in good agreement at all temperature. As the applied temperature increases, the CMC increases, owing to the lower probability of hydrogen bond formation at higher temperatures.The obtained values of the standard Gibbs energy of micellization (ΔGmo) and the standard enthalpy of micellization (ΔHmo) are negative at all investigated temperatures. Thus, one can say that the micellization process and the relationship between drug-water interactions and solute-solute interactions occur at different temperatures. Negative ΔGmo values were recorded when the systems become more hydrophobic. The negative increase in ΔHmo by the increased temperatures can be explained by the exothermic nature of the micellization process. The obtained values of the entropy for micellization (ΔSmo) are positive at all temperatures. The ΔSmo values decrease with temperature increase, this result interpreted as micellazation tend to be energy driven at higher temperatures.Apparent molar volume (V∅), apparent molal volumes at ınfinite dilution (V∅0), micellar apparent molal volumes (V∅mic), changes in apparent molal volumes upon aggregation (ΔVm), apparent molar isentropic compressibilities (K∅(S)), isentropic apparent molal adiabatic compressibilities at infinite dilution (K∅(S)0), micellar ısentropic apparent molal adiabatic compressibilities (K∅(S)m) and changes in isentropic apparent molal adiabatic compressibilities (ΔK∅(S)) of procaine in aqueous solution have been calculated by combining the speed of sound and density measurements. ΔVm are estimated and found to be negative except for 0.43 m3mol−1 (maximum value) at 318.15 K. The variations in these parameters were discussed for micellization process and drug-water interactions and solute-solute interactions at different temperatures.

Chlorpromazine hydrochloride plays a tumor suppressive role in diffuse large B lymphoma by promoting the expression of S1PR2

Objective: To investigate the effect of chlorpromazine hydrochloride on proliferation, apoptosis and cell cycle arrest of human diffuse large B lymphoma cells and its possible mechanism. Methods: In January 2019, OCI-LY3 and TMD8 cells were treated with different concentrations of chlorpromazine hydrochloride for 72 h, the proliferations were detected by Alamar Blue assay. The apoptosis and cell cycle arrest of OCI-LY3 and TMD8 cells were detected by flow cytometry with FITC annexin V/PI (propidium iodide) double staining and PI, respectively. The mRNA levels of cyclin-dependent kinase inhibitor P21, P27, CyclinD1 and S1PR2 were detected by RTqPCR. The protein levels of P21, P27 and S1PR2 were detected by Western blot. Results: With the increase of chlorpromazine hydrochloride concentration, the proliferation inhibition rates of OCI-LY3 and TMD8 cells increased at 72 hours, apoptosis and G1 cell cycle arrest increased at 24 hours. Compared with the control group, the expression levels of P21, P27 and SIPR2 mRNA in OCI-LY3 and TMD8 cells were increased at 10 μmol/L chlorpromazine after 12 hours treatment (P<0.05) . And there was no significant difference in the expression of CyclinD1 mRNA (P>0.05) . There was a similar increase in protein levels of P21, P27 and SIPR2 in OCI-LY3 and TMD8 cells after 24 hours of treatment (P<0.05) . Conclusion: Chlorpromazine hydrochloride at a specific concentration may inhibit the proliferation of ABC diffuse large B lymphoma cells by promoting the expression of S1PR2, and promote cell apoptosis and G1 phase cell cycle arrest.

The fate of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) from livestock wastewater (dominated by quinolone antibiotics) treated by microbial fuel cell (MFC)

The removal characteristics of antibiotic resistance genes and mobile genetic elements from livestock wastewater (dominated by quinolone antibiotics) treated with MFC were evaluated by High-throughput quantitative (HT-qPCR). The results showed that 144 ARGs and 8 MEGs were detected in the livestock wastewater. After MFC treatment, the number of AGRs decreased as a whole, and the relative abundance of macrolide-lincosamide-streptogramin group B (MLSB) and aminoglycosider decreased by 62.7% and 92.9%, respectively. MGEs decreased by 57.3% and multidrug genes decreased by 90%. After MFC treatment, the absolute abundance of tetracycline in raw sewage decreased by two orders of magnitude from 5.8 × 105 copies L−1 to 5.1.× 103 copies L−1. However, MFC was less efficient in the removal of vancomycin and beta-lactamase genes. It was also found that chloramphenicol resistance genes slightly increased. Illumina sequencing showed that Syntrophobacterales and Synergistales were predominant in MFCs. Desulfovibrio was resistant to high concentration of moxifloxacin hydrochloride. The removal efficiency of MFC for moxifloxacin hydrochloride at a concentration of 5 mg L−1 was 86.55%. The maximum power density and coulomb efficiency were 109.3 mV·cm−3 and 41.97%, respectively. With the increase of antibiotic concentration, the sewage treatment efficiency and electrical performance were inhibited. This study shows that untreated livestock wastewater had a great risk of gene horizontal transfer. Although MFC had limited treatment capacity for high-concentration quinolone wastewater, it is an effective method to reduce ARGs and the risk of horizontal gene transfer.

Thiamine in Lipid Systems vs. the Antioxidant Activity of Epigallocatechin Gallate and Caffeine

The aim of this study was to determine correlations between the concentration of thiamine hydrochloride or thiamine pyrophosphate and the antioxidant activity of epigallocatechin gallate (EGCG) and caffeine, as well as thiamine stability. The study was conducted in model systems. Oxidation degree indices of soybean oil (peroxide value and anisidine value LAN) and concentrations of total thiamine were determined. To compare the dynamics of the changes in thiamine content during storage, half-life T1/2 was determined. There was a strong correlation between the stability of thiamine and the stability of the oil. Thiamine was particularly sensitive to secondary oxidation products. Higher losses of thiamine introduced in the form of thiamine pyrophosphate were found (4–6%). The addition of tea components increased fat stability and thus reduced thiamine losses. The dynamics of thiamine loss were found to be lower with EGCG than caffeine. The antioxidant activity of these components was significantly reduced when the content of thiamine (1.0–20.0 mg/100 g) was higher than the natural level in foods. In order to maintain thiamine stability and the high activity of the active tea ingredients, it is necessary to consider their simultaneous addition to the systems in concentrations that limit their interactions.

Effective factors on iontophoretic transdermal delivery of memantine and donepezil as model drugs

The purpose of this study is to compare in vitro and in vivo release characteristics of memantine hydrochloride and donepezil hydrochloride in monolayer films those prepared by the solvent evaporation method. Eudragit EPO (EPO), hydroxypropyl methylcellulose (HPMC), and ethylcellulose (EC) were used as polymer matrix; polyethylene glycol (PEG) was used as a plasticizer, and glycerol (Gl) was used to give balanced monolayer film moisture content. The same matrix were used to load the same concentrations of the model drugs to compare their characteristic release properties and to minimalize the effect of formulation that may affect their specific release properties. Drug-loaded monolayer films were surrounded with cellophane membranes as a barrier on in vitro release studies. The in vivo studies were performed on the shaved (hairless) dorsal region of Wistar albino rats. Anodal iontophoresis was applied as a physical penetration enhancement method for a constant time of 1 h. Linear regression applied to calculate the correlation between the in vivo and in vitro results.Anodal iontophoresis were applied on drug-loaded monolayer films. Iontophoretic results were compared with passive diffusion results of drug-loaded monolayer films. Anodal iontophoresis studies were performed by applying two different current intensities to both lower and higher concentration drug-loaded monolayer films to evaluate the effect of concentration and intensity on the transported drug quantities.The transported average memantine hydrochloride (MEM) and donepezil hydrochloride (DON) concentrations after 24 h passive diffusion study were found as 166.13 ng/mL and, 73.56 ng/mL, respectively. These concentrations were increased to 10.59 μg/mL and, 636.81 ng/mL, respectively after 1 h 0.5 mA/cm2 anodal iontophoretic pre-treatment.The obtained results support the phenomenon; transported drug quantities through the skin from the selected matrix increased according to the concentration of the drug and, the current intensity that applied on iontophoretic pre-treatment. It was observed that the difference between the transported quantities of two drugs depends on mainly to the physicochemical properties of the drugs. Iontophoretic pre-treatment found more effective on transported quantities of memantine hydrochloride through the skin. This supports that the selected matrix and penetration enhancer is sufficient for memantine hydrochloride but not for donepezil hydrochloride. This suggests that the transported donepezil hydrochloride quantities through the skin may increase by the selection of suitable penetration enhancers or combination thereof in a suitable matrix.

Stability of Six Drugs in Total Parenteral Nutrition Solution

Elneopa NF No. 1 and No. 2 infusions are total parenteral nutrition solutions packaged in four-chambered infusion bags. They have been used as home parenteral nutrition, with various drugs injected into the infusion bags, for treating patient symptoms. In this study, we investigated the stability of six drugs, including famotidine, scopolamine butylbromide, furosemide, bromhexine hydrochloride, betamethasone sodium phosphate, and metoclopramide hydrochloride in the infusion bags under dark conditions at 4℃ for 7 days. Additionally, we developed a high-performance liquid chromatography method to determine drug concentrations in the infusions. The concentrations of injected famotidine, scopolamine butylbromide, and betamethasone sodium phosphate remained unchanged when the four chambers of Elneopa NF No. 1 and No. 2 were opened and the infusions were mixed. Their respective concentrations in the upper and lower chambers also remained unchanged. The concentration of furosemide in the upper chamber of the No. 1 infusion bag decreased after 5 days, although no change was observed in the other chambers and the mixed infusions with the four chambers opened. The concentration of bromhexine hydrochloride slightly decreased in the upper chambers (approximately 3%) after the co-infusion but decreased significantly in the other chambers and the mixed infusions with the four chambers opened. The concentration of metoclopramide hydrochloride significantly decreased in the upper chambers after the co-infusion; however, no change in concentration was observed in the other chambers and the mixed infusion with the four chambers opened. The results of this study provide useful information on home-based parenteral nutrition.

Influence of 2-Ethyl-6-Methyl-3-Hydroxypyridine on the Functional State of Rat Liver Mitochondria In Vitro

The influence of 2-ethyl-6-methyl-3-hydroxypyridine hydrochloride on the in vitro free-radical oxidation and respiration of intact rat liver mitochondria was studied. The drug used at a concentration within the pharmacokinetic range had a modulating effect on lipid peroxidation and oxidative modification of mitochondrial proteins. Emoxypine hydrochloride caused transient accumulation of lipid peroxidation products at relatively high concentrations in the incubation mixture (~10–3 M) and redistribution of free-radical oxidation substrates in favor of proteins with a gradual restriction of oxidative phosphorylation, a decrease in affinity of the respiratory chain to ADP, and an impaired intactness of mitochondrial structures reaching the most significant values at emoxypine hydrochloride concentrations of 10–8 and 10–9 M.

Solvolysis Thermodynamic Parameters of Phenyl Hydrazine Hydrochloride

AbstractThe present work deals with studying the effect of solvent and temperature on the solvolysis process using both the pH-metric and the conductometric measurements. The pH and the conductivity of different concentrations of the phenyl hydrazine hydrochloride in water (H2O), ethanol (EtOH) and in (EtOH-H2O) mixtures with different percentages of EtOH; 30%, 50%, 70%, 100% (v/v) and at different temperatures from 293.15 to 308.15 K with a step of 5 K were measured experimentally. The conductivity of different concentrations of the phenyl hydrazine hydrochloride in aniline at the same temperatures was also measured. Depending on the measured pH and conductivity data, the solvolysis constant of phenyl hydrazine chloride was estimated. The thermodynamic parameters (free energy change, , enthalpy change, , entropy change, , and activation energy, ) of the solvolysis process were evaluated from the temperature dependence of solvolysis constant. Positive values of the standard enthalpy change ( ), indicate that the solvolysis process is endothermic process. The solvolysis constant is increase as the alcohol percentage increase from 30% - 100%, which attributed to the higher solute-solvent interaction.

Unidirectional Water-Transport Antibacterial Trilayered Nanofiber-Based Wound Dressings Induced by Hydrophilic-Hydrophobic Gradient and Self-Pumping Effects

Excessive wound exudates often cause infection and hinder wound repair and regeneration. It is therefore urgently needed to develop an ideal wound dressing for pumping the excessive biofluids and inhibiting bacterial infection in the wound healing process. Herein, we demonstrate a facile and efficient strategy to fabricate the unidirectional water-transport antibacterial wound dressings by embedding macromolecular antimicrobials into a multilayer nanofibrous membrane featured with hydrophobic-to-hydrophilic gradient structure and self-pumping effect using an electrospinning technique. Thanks to these features, the obtained nanofibrous dressings achieved excellent unidirectional water-transport performance, which could drive wound exudates to flow spontaneously from inside to outside and prevent pumped biofluids rewetting the wounds. In addition, the designed trilayered dressing exhibited approximately 100% antibacterial ability against Staphylococcus aureus and Escherichia coli when the concentration of antibacterial agents polyhexamethylene guanidine hydrochloride (PHGC) was 0.06 wt%. Moreover, the trilayered dressings revealed excellent water absorption performance, air and moisture permeability, mechanical strength, biocompatibility, and low cell adhesion behavior, indicating the potential applications for the trilayered nanofibrous wound dressings in wound care.

P0660 / #2106: COMPATIBILITY BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY OF VANCOMYCIN HYDROCHLORIDE AND SODIUM HEPARIN USED IN CENTRAL LINES ANTIMICROBIAL LOCK THERAPY

Aims & Objectives: To verify compatibility of vancomycin hydrochloride in association with sodium heparin, according to the influence of time and temperature. Methods: Experimental study, simulating the clinical practice of antimicrobial lock in central intravenous lines performed in severely ill children. The concentration was analyzed in triplicate by High Performance Liquid Chromatography (HPLC). The analytical method was validated. Drugs concentrations were 5mg/mL of vancomycin hydrochloride and 100U.I./mL of sodium heparin in saline solutions. The sample consisted of 06 solutions (03 at 22°C and 03 at 37°C) maintained in the absence of light. The HPLC analyzes occurred at times zero (T0), 3 (T3), 8 (T8) and 24 (T24) hours resulting in 72 chromatograms. Results: The vancomycin hydrochloride and sodium heparin solutions at 22°C resulted in a reduction (p < 0.001) of vancomycin hydrochloride concentration in 24 hours (4.82±0.08mg/mL; 96.34±1.70%); the same solution at 37°C resulted in vancomycin hydrochloride lower concentrations (p=0.001) since the initial moment of drugs association (T0=4.75±0.09mg/mL or 94.91±1.76%; T3=4.76±0.06mg/mL or 95.12±1.29%; T8=4.75±0.16mg/mL or 95.05±3.15%; T24=4.85±0.06mg/mL or 96.94±1.23%). During drugs association, at both temperatures, precipitate formation was observed after three hours. Conclusions: The concentration of vancomycin hydrochloride associated to sodium heparin presented variations below 10% leading to the conclusion of chemical compatibility until 24 hours. The solutions showed physical incompatibility after 3 hours of drugs association.

Simultaneous Determination of Chloroquine and Pyrimethamine with Cetirizine in an Active Form and Human Serum by RP-HPLC.

A simple, accurate and precise RP-HPLC method was developed for the simultaneous determination of chloroquine, pyrimethamine and cetirizine hydrochloride concentrations in bulk drug and human serum. The assay was performed using a mobile phase of methanol: water (70:30) at pH of 2.8±0.05 on the Purospher C-18 column with UV detection at 230nm and rosuvastatin used as an internal standard. The retention times observed for chloroquine, pyrimethamine and cetirizine hydrochloride were 3.5, 2.5 and 5.5minutes, respectively. The method was found to be specific for the assayed drugs showing a linear response in the concentration range of 1-100μg mL-1 with coefficients of determination values of (r=0.999). The method was developed and validated according to ICH guidelines. The method was used to monitor the serum samples and was found to be sensitive for therapeutic purposes, showing the potential to be a useful tool for routine analysis in laboratories.

Topical administration of ambroxol eye drops augments tear secretion in rabbits.

To investigate if topical administration of ambroxol promotes tear secretion and to compare with Diquas ophthalmic eye drop. Two consecutive studies were conducted using sixteen (32 eyes) New Zealand White rabbits. The first study compared the efficacy of ambroxol hydrochloride (0.05%, 0.2%, and 1.0%) on tear and mucin secretion when administered twice daily. Tear secretion was assessed by Schirmer test I and mucin production by conjunctival impression cytology and PAS stain. The second study compared 0.2% ambroxol hydrochloride with Diquas. A human goblet cell line and human conjunctival tissue were used to test the effect of ambroxol hydrochloride on the expression of aquaporin 5 (AQP5) and MUC5AC, using reverse transcriptase-quantitative polymerase chain reaction and immunoblotting. All three concentrations of ambroxol hydrochloride demonstrated significant efficacy on tear stimulation within 2 weeks of treatment and total mucin component appeared increased. When administered topically twice daily, 0.2% ambroxol hydrochloride was more effective in augmenting tear secretion than Diquas. With 24 h of treatment, 5 μM of ambroxol hydrochloride upregulated AQP5 and MU5AC mRNA and MUC5AC protein in a goblet cell line. When tested on preserved human conjunctiva tissue, a trend of increased production of MUC5AC protein was seen (P = 0.26). Ambroxol is effective in augmenting tear secretion at the ocular surface in rabbits. With actions desirable of a candidate dry eye drug, further investigation of ambroxol and related compounds is warranted to explore their value toward clinical application.

Unidirectional water-transport antibacterial trilayered nanofiber-based wound dressings induced by hydrophilic-hydrophobic gradient and self-pumping effects

Excessive wound exudates often cause infection and hinder wound repair and regeneration. It is therefore urgently needed to develop an ideal wound dressing for pumping the excessive biofluids and inhibiting bacterial infection in the wound healing process. Herein, we demonstrate a facile and efficient strategy to fabricate the unidirectional water-transport antibacterial wound dressings by embedding macromolecular antimicrobials into a multilayer nanofibrous membrane featured with hydrophobic-to-hydrophilic gradient structure and self-pumping effect using an electrospinning technique. Thanks to these features, the obtained nanofibrous dressings achieved excellent unidirectional water-transport performance, which could drive wound exudates to flow spontaneously from inside to outside and prevent pumped biofluids rewetting the wounds. In addition, the designed trilayered dressing exhibited approximately 100% antibacterial ability against Staphylococcus aureus and Escherichia coli when the concentration of antibacterial agents polyhexamethylene guanidine hydrochloride (PHGC) was 0.06 wt%. Moreover, the trilayered dressings revealed excellent water absorption performance, air and moisture permeability, mechanical strength, biocompatibility, and low cell adhesion behavior, indicating the potential applications for the trilayered nanofibrous wound dressings in wound care.

Investigating the interaction of terbinafine with xanthenes dye for its feasible determination applying the resonance Rayleigh scattering technique.

Terbinafine hydrochloride is a potent antifungal drug indicated for oral and topical treatment of mycoses. A resonance Rayleigh scattering (RRS) method was developed for the determination of terbinafine hydrochloride through a feasible complexation reaction with erythrosine B. In a weakly acidic medium (acetate buffer, pH 5.0), terbinafine hydrochloride can react with erythrosine B through the electrostatic attraction and virtue of hydrophobic force to form an ion-association complex. The reaction resulted in the appearance of a new RRS peak at 369 nm. The RRS peak was increased by increasing the concentration of terbinafine hydrochloride in the linear range of 0.1–1.5 µg ml−1. All the reaction conditions (erythrosine B concentration, buffer volume, diluting solvent and pH) were optimized. The detection limit was 0.029 µg ml−1 while the quantitation limit was 0.089 µg ml−1. The suggested method after its validation was successfully applied for the determination of terbinafine hydrochloride in different pharmaceutical formulations (tablets and cream) with sufficient recovery.

Histological assessment of the local effect of different concentrations of aminoguanidine hydrochloride on bone healing in rats

Nitric oxide (NO) has several functions in bone healing and affects bone metabolism. Selective inducible NO synthase (iNOS) inhibitors can be used to assess the efficacy of NO for healing of bone defects. This study sought to assess the local effect of different concentrations of aminoguanidine hydrochloride (AG), a selective iNOS inhibitor, on bone healing in rats. In this animal experimental study, 72 rats were divided into six groups of control, placebo, 5% AG, 10% AG, 15% AG, and 20% AG. A bone defect measuring 5 mm × 5 mm was created in the femur. The defect remained empty in the control group. In the placebo group, neutral gel was placed in the bone defect, and in the remaining four AG groups, different concentrations of AG were applied to the defects. Bone healing was assessed histologically. The healing score in the six groups was analyzed by the Kruskal-Wallis test. A P < 0.05 was considered statistically significant. The healing score in 20%, 15%, 10%, and 5% AG groups was significantly higher than that in the neutral gel and control groups (P < 0.01). Among the four groups of AG, 20% concentration showed better results, but the difference was not significant. Four concentrations of AG caused greater bone healing compared to the other two groups. Selective iNOS inhibitors such as AG can be used to promote local bone healing.

Effect of berberine hydrochloride on cell wall integrity of Candida albicans hypha

The aim of this paper was to investigate the effect of berberine hydrochloride on the cell wall integrity of Candida albicans hypha. The minimal inhibitory concentration(MIC) of berberine hydrochloride against clinical and standard C. albicans strains was detected by micro liquid-based dilution method; the effect of berberine hydrochloride on the colony formation of C. albicans SC5314 was investigated by spot assay; the effect of berberine hydrochloride on the metabolism of C. albicans SC5314 hypha was checked by XTT reduction assay, and the viability of C. albicans SC5314 hypha was tested by fluorescent staining assay. The effect of berberine hydrochloride on the morphology of C. albicans SC5314 hypha was examined by scanning electron microscope. The changes in the cell wall of C. albicans SC5314 hypha after berberine hydrochloride treatment were detected by transmission electron microscopy. The effect of berberine hydrochloride on β-glucan from C. albicans SC5314 was detected by flow cytometry. The effect of berberine hydrochloride on hypha-specific gene ECE1 and β-glucan synthase genes FKS1 and FKS2 in C. albicans was examined by qRT-PCR. The results showed that berberine hydrochloride showed a strong inhibitory effect on both clinical and standard strains of C. albicans, and the MIC was 64-128 μg·mL~(-1). Spot assay, XTT redunction assay and fluorescent staining assay showed that with the increase of berberine hydrochloride concentration, the viability of C. albicans SC5314 gradually decreased. The transmission electron microscopy scanning assay showed that this compound could cause cell wall damage of C. albicans. The flow cytometry analysis showed the exposure degree of C. albicans β-glucan. The qRT-PCR further showed that berberine hydrochloride could significantly down-regulate hypha-specific gene ECE1 and β-glucan synthase-related gene FKS1 and FKS2. In conclusion, this compound can down-regulate C. albicans and β-glucan synthase-related gene expressions, so as to destroy the cell wall structure of C. albicans, expose β-glucan and damage the integrity of the wall.

Transdermal iontophoresis delivery system for terazosin hydrochloride: an in vitro and in vivo study

This study aimed to construct a transdermal iontophoresis delivery system for terazosin hydrochloride (IDDS-TEH), which included a positive and negative electrode hydrogel prescription. Intact guinea pig skin was used as a model for the skin barrier function, and the current intensity, terazosin hydrochloride (TEH) concentration, pH, competitive salt, and transdermal enhancer properties were studied. The blood drug concentration was determined in Sprague–Dawley (SD) rats using HPLC, and the antihypertensive effects of IDDS-TEH were evaluated in spontaneously hypertensive rats (SHRs). The results showed that the steady-state penetration rate of TEH increased (from 80.36 µg·cm−2·h−1 to 304.93 µg·cm−2·h−1), followed by an increase in the current intensity (from 0.10 mA·cm−2 to 0.49 mA·cm−2). The pH values also had a significant influence on percutaneous penetration. The blood concentration of IDDS-TEH was significantly higher (p < .05) than with passive diffusion, which could not be detected. The main pharmacokinetic parameters of the high current group (0.17 mA·cm−2) and the low current group (0.09 mA·cm−2) were AUC0– t : 5873.0 ng·mL−1·h and 2493.7 ng·mL−1·h, respectively. Meanwhile, the pharmacodynamic results showed that IDDS-TEH significantly decreased the blood pressure of SHRs compared with the TEH hydrogel without loading current. Therefore, TEH could be successfully delivered by the transdermal iontophoresis system in vitro and in vivo, and further clinical studies should be explored to develop a therapeutically useful protocol.

Determination of tetracycline hydrochloride in pure and pharmaceutical samples via oxidative coupling reaction

Due to the importance of tetracycline hydrochloride in the medical field and in the pharmaceutical industry, a simple and sensitive spectrophotometric method was used to determine the trace amount of tetracycline hydrochloride (TCH) in this study by using oxidative coupling reactions. This work relied on the reaction of 2,4-dinitrophenylhydrazine (2,4-DNPH) with potassium periodate in a basic medium (pH 12.9) to form a diazonium salt that combined with tetracycline hydrochloride, resulting in a stable, water-soluble orange dye with an absorbance of 488 nm. When absorbance is plotted against the estimated substance concentration, this indicates that the method follows Beer’s law in the concentration rang of 2.0–50 μg.ml −1 of tetracycline hydrochloride (TCH) in a final volume of 25 ml with relative standard deviation percent (R.S.D) < 0.58% and accuracy, expressed by recovery percent (99.75%) for five levels of tetracycline hydrochloride (TCH) concentration. the molar absorptivity value is 1.2503 × 10 4 L. mol −1 .cm -1 and the Sandell’s sensitivity index is 3.8461 × 10 −2 μg. Cm −2 , this study was applied with success in the analysis of some pharmaceutical preparations containing tetracycline by standard addition method and for two levels of concentration.

An Innovative Spectrophotometric Method for the Estimation of H1 Receptor Antagonists in Pharmaceutical Formulations

An innovative, sensitive, simple and rapid method has been developed for estimation of selective H1 receptor antagonist. The method is based on bromination of drug. The proposed spectrophotometric method was developed using potassium bromate-potassium bromide mixture in acidic condition followed by the reaction of surplus bromine with methyl orange dye and measure the absorbance at 506 nm. Beer’s law was obeyed in the concentration range of 0.2-1.2 μg/ml, 0.3-1.7 μg/ml and 0.03-0.18 μg/ml for olopatadine hydrochloride, fexofenadine hydrochloride and azelastine hydrochloride respectively. The method was optimized for concentration of hydrochloride, ml of hydrochloride, ml of potassium bromate-potassium bromide mixture, ml of dye and reaction time. Developed method has been validated in accordance to International Council on Harmonisation guideline Q2R1. Statistical analysis proved that the method is accurate, sensitive, selective, precise and reproducible. The simple procedure with high accuracy, wide linearity range and sensitivity imply that the demonstrated method to be appropriate for routine estimation and quality control assay of pharmaceutical formulations.