Reversed phase high-performance liquid chromatography (RP-HPLC) and thin-layer chromatography (TLC)-spectrodensitometric methods have been developed and validated for the separation and quantitation of two binary mixtures: Ofloxacin (OFX) and dexamethasone (DXM) in eye preparation; ciprofloxacin hydrochloride (CIP) and hydrocortisone (HYD) in ear preparation. The linearity ranges of RP-HPLC methods were found to be (2.5–45 μg mL−1) for OFX, (2.5–50 μg mL−1) for DXM and (1–8 μg mL−1) for both CIP and HYD. The percentage recoveries/relative standard deviation (RSD) were found to be 100.36/1.38, 100.13/1.49, 99.98/0.61 and 100.28/1.27, respectively. The linearity ranges of TLC-spectrodensitometric methods were found to be (0.5–2 μg band−1), (0.5–3.5 μg band−1), (0.2–1.6 μg band−1), and (0.6–2 μg band−1) for OFX, DXM, CIP, and HYD, respectively. The percentage recoveries/RSD were found to be 99.98/1.06, 99.93/1.18, 99.74/1.27, and 99.94/1.54, respectively. A comparative study was conducted to show the advantages of the proposed methods which showed that the TLC-spectrodensitometric methods were simpler, more sensitive, and economic, while RP-HPLC methods were more precise and robust. The methods were validated in compliance with the ICH guidelines and were successfully applied for determination of the selected drugs in their laboratory-prepared mixtures and commercial dosage forms.

Abstract: A validated simple, rapid, and selective spectrofluorimetric method was developed for the determination of some non-sedating antihistamines (NSAs); namely cetirizine (CTZ), ebastine (EBS), fexofenadine (FXD), ketotifen (KET), and loratadine (LOR). The method is based on quenching effect of the cited drugs on the fluorescence intensity of erythrosine B (EB) by the formation of ion-pair complex measured without extraction at lex.. 311 nm/ lex.. 555 nm against a reagent blank. The fluorescence intensity of EB was diminished when the studied drugs were added. There was a linear relationship between the fluorescence quenching value of the system (ΔF = F EB – F Drug–EB) and the concentration of the investigated drug. Under the optimal conditions, the linear ranges of calibration curves for the determination of the studied NSAs were 0.25–2.0, 0.25–3.0, and 0.25–6.0
g/mL for (CTZ, KET, LOR), (EBS), and (FXD), respectively. The factors affecting the formation of the ion-pair complex were carefully studied and optimized. The method was validated according to ICH guidelines. The suggested method is applicable for the determination of the five investigated drugs in bulk and pharmaceutical dosage forms with excellent recoveries (98.23-103.77 %).

Abstract: A validated simple, rapid, and selective spectrofluorimetric method was developed for the determination of some non-sedating antihistamines (NSAs); namely cetirizine (CTZ), ebastine (EBS), fexofenadine (FXD), ketotifen (KET), and loratadine (LOR). The method is based on quenching effect of the cited drugs on the fluorescence intensity of erythrosine B (EB) by the formation of ion-pair complex measured without extraction at lex.. 311 nm/ lex.. 555 nm against a reagent blank. The fluorescence intensity of EB was diminished when the studied drugs were added. There was a linear relationship between the fluorescence quenching value of the system (ΔF = F EB – F Drug–EB) and the concentration of the investigated drug. Under the optimal conditions, the linear ranges of calibration curves for the determination of the studied NSAs were 0.25–2.0, 0.25–3.0, and 0.25–6.0
g/mL for (CTZ, KET, LOR), (EBS), and (FXD), respectively. The factors affecting the formation of the ion-pair complex were carefully studied and optimized. The method was validated according to ICH guidelines. The suggested method is applicable for the determination of the five investigated drugs in bulk and pharmaceutical dosage forms with excellent recoveries (98.23-103.77 %).

Abstract: A validated simple, rapid, and selective spectrofluorimetric method was developed for the determination of some non-sedating antihistamines (NSAs); namely cetirizine (CTZ), ebastine (EBS), fexofenadine (FXD), ketotifen (KET), and loratadine (LOR). The method is based on quenching effect of the cited drugs on the fluorescence intensity of erythrosine B (EB) by the formation of ion-pair complex measured without extraction at lex.. 311 nm/ lex.. 555 nm against a reagent blank. The fluorescence intensity of EB was diminished when the studied drugs were added. There was a linear relationship between the fluorescence quenching value of the system (ΔF = F EB – F Drug–EB) and the concentration of the investigated drug. Under the optimal conditions, the linear ranges of calibration curves for the determination of the studied NSAs were 0.25–2.0, 0.25–3.0, and 0.25–6.0
g/mL for (CTZ, KET, LOR), (EBS), and (FXD), respectively. The factors affecting the formation of the ion-pair complex were carefully studied and optimized. The method was validated according to ICH guidelines. The suggested method is applicable for the determination of the five investigated drugs in bulk and pharmaceutical dosage forms with excellent recoveries (98.23-103.77 %).

Abstract: A validated simple, rapid, and selective spectrofluorimetric method was developed for the determination of some non-sedating antihistamines (NSAs); namely cetirizine (CTZ), ebastine (EBS), fexofenadine (FXD), ketotifen (KET), and loratadine (LOR). The method is based on quenching effect of the cited drugs on the fluorescence intensity of erythrosine B (EB) by the formation of ion-pair complex measured without extraction at lex.. 311 nm/ lex.. 555 nm against a reagent blank. The fluorescence intensity of EB was diminished when the studied drugs were added. There was a linear relationship between the fluorescence quenching value of the system (ΔF = F EB – F Drug–EB) and the concentration of the investigated drug. Under the optimal conditions, the linear ranges of calibration curves for the determination of the studied NSAs were 0.25–2.0, 0.25–3.0, and 0.25–6.0
g/mL for (CTZ, KET, LOR), (EBS), and (FXD), respectively. The factors affecting the formation of the ion-pair complex were carefully studied and optimized. The method was validated according to ICH guidelines. The suggested method is applicable for the determination of the five investigated drugs in bulk and pharmaceutical dosage forms with excellent recoveries (98.23-103.77 %).

Ferutinin (1), the major constituent of Ferula hermonis and other Ferula species, is a sesquiterpene ester with remarkable estrogenic activity, beside other valuable medicinal properties. To investigate the influence of chemical modification of the ferutinin structure on its estrogenic effect and binding affinity toward the cannabinoid CB1 and CB2 receptors, twelve derivatives of 1 were prepared and evaluated in vitro, together with the parent compound, for the respective bioactivities, based on the recent evidence for estrogen–endocannabinoid interaction. Nine of the prepared derivatives (3–11) are new semisynthetic esters of 1. The parent compound ferutinin (1) exhibited the highest level of estrogenic activity (EC50 0.3 μM and a percent maximal 17β-estradiol response of 90 % at 1 µM). Compound 6 was found to be a selective agonist for CB2 receptor (EC50 0.051 μM, Ki 0.025 μM), with much less affinity for CB1 receptor (EC50 97 μM, Ki 48.5 μM). Compound 8 was a selective agonist for CB1 (EC50 62, Ki 0.031 μM) with no affinity toward CB2.

An endophyte Bartalinia pondoensis Marinc of Citrus aurantum L. var. dulcis was isolated and studied for its secondary metabolites and for their Mycobacterium tuberculosis shikimate kinase (MtSK) inhibitory activities. Using LC–MS metabolite fingerprinting of the constituents of the methanol extract, 19 compounds pertaining to various classes were identified: amino acids, proto-alkaloids, fatty acid amides and oxazole, aniline derivatives and aromatic compounds. We report here for the first time the presence of the [N-(ethyloxy, hydroxymethyl)phenylethylamine] as a new proto-alkaloid and 18 other known compounds are reported for the first time in the genus of Bartalinia. MtSK inhibitory activities of methanol extract and fractions obtained by solid phase extraction (SPE) at a concentration of 50 µg/mL may be attributed to the presence of aniline and oxazole derivatives present in all fractions in varying concentrations.