Nitrite (NO2−), an important intermediate in the biological nitrogen cycle, can be considered as a life-threatening marker since it leads to the production of carcinogenic nitrosamines when it reacts with secondary amines in the digestive system, besides being a methemoglobinemia risk factor in the children. Herein, we reported a fluorescence detection method for rapid, selective, and sensitive detection of NO2− in water samples. The method is based on the modification of α-MnO2 nanorods with fluorescein dye (FLR@ α-MnO2 NR) where the former acts as a quencher and the latter acts as a fluorescence reporter. After the addition of NO2− to the FLR@ α-MnO2 NR system, it reduces α-MnO2 NR to soluble Mn2+ and liberates FLR, restoring the fluorescence of FLR (Turn On). The nanoprobe, with λex/λem at 490/518 nm, has a linear range of 0.83–67.0 µM with a limit of detection (LOD) of 0.27 µM, for analysis of NO2−. The proposed method was successfully applied to the determination of NO2− in natural water samples.

Nitrite (NO2−), an important intermediate in the biological nitrogen cycle, can be considered as a life-threatening marker since it leads to the production of carcinogenic nitrosamines when it reacts with secondary amines in the digestive system, besides being a methemoglobinemia risk factor in the children. Herein, we reported a fluorescence detection method for rapid, selective, and sensitive detection of NO2− in water samples. The method is based on the modification of α-MnO2 nanorods with fluorescein dye (FLR@ α-MnO2 NR) where the former acts as a quencher and the latter acts as a fluorescence reporter. After the addition of NO2− to the FLR@ α-MnO2 NR system, it reduces α-MnO2 NR to soluble Mn2+ and liberates FLR, restoring the fluorescence of FLR (Turn On). The nanoprobe, with λex/λem at 490/518 nm, has a linear range of 0.83–67.0 µM with a limit of detection (LOD) of 0.27 µM, for analysis of NO2−. The proposed method was successfully applied to the determination of NO2− in natural water samples.

Indigo carmine (IC) dye is hazardous and allergenic for humans even though it has been excessively used in a wide range of industries. Therefore, the quantitative determination of IC is still challenging. Herein, for the first time, we have developed fluorometric and colorimetric dual-mode nanoprobe derived from the ion-pair association complex between the negatively charged IC and positively charged N@C-dots in pH =3.0. Consequently, the binding between N@C-dots and IC resulted in cyan blue and quenching of N@C-dots fluorescence. The dependence of the fluorescence response on IC concentrations was linear over the range of 0.73 –10.0 µM (R2=0.9989) with LOD of 0.24 µM. On the other hand, the linearity of the colorimetric method ranged from 9.97 – 80.0 µM (R2=0.9986) with LOD of 3.3 µM. The sensor was applied for estimation of IC in fruit juice and soft drink without the need for exhaustive extraction steps.

Indigo carmine (IC) dye is hazardous and allergenic for humans even though it has been excessively used in a wide range of industries. Therefore, the quantitative determination of IC is still challenging. Herein, for the first time, we have developed fluorometric and colorimetric dual-mode nanoprobe derived from the ion-pair association complex between the negatively charged IC and positively charged N@C-dots in pH =3.0. Consequently, the binding between N@C-dots and IC resulted in cyan blue and quenching of N@C-dots fluorescence. The dependence of the fluorescence response on IC concentrations was linear over the range of 0.73 –10.0 µM (R2=0.9989) with LOD of 0.24 µM. On the other hand, the linearity of the colorimetric method ranged from 9.97 – 80.0 µM (R2=0.9986) with LOD of 3.3 µM. The sensor was applied for estimation of IC in fruit juice and soft drink without the need for exhaustive extraction steps.

The aim of this study was to enhance the dissolution rate of water-insoluble, weakly basic antiemetic drug; Domperidone (DMP), through the formulation of adsorbates and co-adsorbates. Adsorption of drug onto the surface of three different adsorbents; Avicel PH 101, Florite R and Aerosil 200 was studied and Langmuir adsorption isotherms were constructed. Adsorbates of drug with the used adsorbents were prepared in different weight ratios by physical mixing, grinding and solvent evaporation methods. Co-adsorbates of drug with Aerosil 200 and Tween 80 were prepared by solvent evaporation method in different weight ratios. The prepared systems were physico-chemically characterized by Fourier- transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and powder X-ray diffractometry (P-XRD). FT-IR data confirmed the absence of any chemical interaction between DMP and the used adsorbents. P-XRD results confirmed the transformation of some systems from the crystalline state to the amorphous state which aided in the dissolution rate enhancement. Furthermore, the in-vitro dissolution rate of drug from these systems was studied which showed marked enhancement of DMP dissolution rate at both pH 1.2 and pH 6.8 (7 fold and 5 fold, respectively) compared to drug alone .It can be concluded that the dissolution rate

The aim of this study was to enhance the dissolution rate of water-insoluble, weakly basic antiemetic drug; Domperidone (DMP), through the formulation of adsorbates and co-adsorbates. Adsorption of drug onto the surface of three different adsorbents; Avicel PH 101, Florite R and Aerosil 200 was studied and Langmuir adsorption isotherms were constructed. Adsorbates of drug with the used adsorbents were prepared in different weight ratios by physical mixing, grinding and solvent evaporation methods. Co-adsorbates of drug with Aerosil 200 and Tween 80 were prepared by solvent evaporation method in different weight ratios. The prepared systems were physico-chemically characterized by Fourier- transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and powder X-ray diffractometry (P-XRD). FT-IR data confirmed the absence of any chemical interaction between DMP and the used adsorbents. P-XRD results confirmed the transformation of some systems from the crystalline state to the amorphous state which aided in the dissolution rate enhancement. Furthermore, the in-vitro dissolution rate of drug from these systems was studied which showed marked enhancement of DMP dissolution rate at both pH 1.2 and pH 6.8 (7 fold and 5 fold, respectively) compared to drug alone .It can be concluded that the dissolution rate

The aim of this study was to enhance the dissolution rate of water-insoluble, weakly basic antiemetic drug; Domperidone (DMP), through the formulation of adsorbates and co-adsorbates. Adsorption of drug onto the surface of three different adsorbents; Avicel PH 101, Florite R and Aerosil 200 was studied and Langmuir adsorption isotherms were constructed. Adsorbates of drug with the used adsorbents were prepared in different weight ratios by physical mixing, grinding and solvent evaporation methods. Co-adsorbates of drug with Aerosil 200 and Tween 80 were prepared by solvent evaporation method in different weight ratios. The prepared systems were physico-chemically characterized by Fourier- transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and powder X-ray diffractometry (P-XRD). FT-IR data confirmed the absence of any chemical interaction between DMP and the used adsorbents. P-XRD results confirmed the transformation of some systems from the crystalline state to the amorphous state which aided in the dissolution rate enhancement. Furthermore, the in-vitro dissolution rate of drug from these systems was studied which showed marked enhancement of DMP dissolution rate at both pH 1.2 and pH 6.8 (7 fold and 5 fold, respectively) compared to drug alone .It can be concluded that the dissolution rate

The aim of this study was to enhance the dissolution rate of water-insoluble, weakly basic antiemetic drug; Domperidone (DMP), through the formulation of adsorbates and co-adsorbates. Adsorption of drug onto the surface of three different adsorbents; Avicel PH 101, Florite R and Aerosil 200 was studied and Langmuir adsorption isotherms were constructed. Adsorbates of drug with the used adsorbents were prepared in different weight ratios by physical mixing, grinding and solvent evaporation methods. Co-adsorbates of drug with Aerosil 200 and Tween 80 were prepared by solvent evaporation method in different weight ratios. The prepared systems were physico-chemically characterized by Fourier- transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and powder X-ray diffractometry (P-XRD). FT-IR data confirmed the absence of any chemical interaction between DMP and the used adsorbents. P-XRD results confirmed the transformation of some systems from the crystalline state to the amorphous state which aided in the dissolution rate enhancement. Furthermore, the in-vitro dissolution rate of drug from these systems was studied which showed marked enhancement of DMP dissolution rate at both pH 1.2 and pH 6.8 (7 fold and 5 fold, respectively) compared to drug alone .It can be concluded that the dissolution rate

The aim of this work was to enhance the oral bioavailability of water-insoluble, weaklybasic, anti-emetic drug; Domperidone (DMP), which has a poor oral bioavailability (13-17%). Adsorption of drug onto the surface of Aerosil 200 was achieved by solvent evaporation method to enhance the drug dissolution rate. Then, the adsorbates were formulated into gastro-retentive floating tablets to retain the drug in the acidic medium of stomach which is favorable for the drug dissolution. Different drug: adsorbent ratios were prepared and tested for their in-vitro dissolution rate to select the best ratio for the final formulation. Different concentrations of several polymers were used in the preparation of tablets matrices together with sodium bicarbonate to induce the floating effect via reaction with gastric HCl. Drug-excipient compatibility studies were performed using Fouriertransform Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC)which confirmed the absence of incompatibilities between the drug and the used excipients. The tablets were prepared by direct compression technique and evaluated for their weight uniformity, drug content, friability, hardness, thickness, floating properties, in-vitro dissolution rate and kinetics of drug release. Formulae F7 (containing 30% w/w sodium alginate) and F8 (containing 40% w/w sodium alginate) showed the best results and thus; they were selected for in-vivo studies in rabbits. The selected formulae showed marked enhancement of domperidone bioavailability compared with the commercial conventional immediate-release tablets; Motinorm®, with relative bioavailability values of 298.26±11.53% and 315.04±13.39% for F7 and F8, respectively and proved that the selected formulae successfully controlled the drug release.

The aim of this work was to enhance the oral bioavailability of water-insoluble, weaklybasic, anti-emetic drug; Domperidone (DMP), which has a poor oral bioavailability (13-17%). Adsorption of drug onto the surface of Aerosil 200 was achieved by solvent evaporation method to enhance the drug dissolution rate. Then, the adsorbates were formulated into gastro-retentive floating tablets to retain the drug in the acidic medium of stomach which is favorable for the drug dissolution. Different drug: adsorbent ratios were prepared and tested for their in-vitro dissolution rate to select the best ratio for the final formulation. Different concentrations of several polymers were used in the preparation of tablets matrices together with sodium bicarbonate to induce the floating effect via reaction with gastric HCl. Drug-excipient compatibility studies were performed using Fouriertransform Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC)which confirmed the absence of incompatibilities between the drug and the used excipients. The tablets were prepared by direct compression technique and evaluated for their weight uniformity, drug content, friability, hardness, thickness, floating properties, in-vitro dissolution rate and kinetics of drug release. Formulae F7 (containing 30% w/w sodium alginate) and F8 (containing 40% w/w sodium alginate) showed the best results and thus; they were selected for in-vivo studies in rabbits. The selected formulae showed marked enhancement of domperidone bioavailability compared with the commercial conventional immediate-release tablets; Motinorm®, with relative bioavailability values of 298.26±11.53% and 315.04±13.39% for F7 and F8, respectively and proved that the selected formulae successfully controlled the drug release.