Aloe leaf latex is a commonly used plant preparation in traditional medicine. However, quality co... more Aloe leaf latex is a commonly used plant preparation in traditional medicine. However, quality control on the content of medicinally important constituents is often limited. Hence, establishing a reliable quality control method to identify and quantify bioactive markers is important to ensure safety and efficacy. In the present study, a novel liquid chromatographic (LC) method was developed and validated for efficient analysis of bioactive markers to evaluate the quality of aloe leaf latex. Quantification of marker compounds was possible in only 7 min on a monolithic column using gradient elution with 0.1 % formic acid in acetonitrile and water as mobile phases. The major compounds (aloins A and B) could be baseline separated together with related compounds within 10 min. The method showed excellent linearity with determination coefficients (r2) of 0.9999. Detection limits were 0.017 and 0.013 μg/mL, while quantification limits were 0.057 and 0.043 μg/mL for aloin A and aloin B, respectively. Relative standard deviation (RSD) values for intra- and inter-day precision were less than 2% and recoveries for both aloins were close to 100 %. The robustness was evaluated using an experimental design. The method was applied to some aloe leaf latex samples from Ethiopia. Aloin contents varied from 14 to 35 % and two unknown peaks were tentatively identified as aloinoside and microdontin.
Background: Khat chewing practice has increased over the years and chronic khat use is associated... more Background: Khat chewing practice has increased over the years and chronic khat use is associated with adverse health and socio-economic effects. Thus, this study was undertaken among khat chewers in Mekelle town, northern Ethiopia to investigate socio-economic and health-related effects of khat chewing. Methods: A cross-sectional study was conducted in Mekelle from April to May 2016 with the help of a structured questionnaire to collect data. Simple random sampling method was used to select the respondents. Descriptive statistics were employed for summarization and presentation of data. Results: Khat chewing was most commonly practiced among male gender (87.1%), productive age group (94.7%), Orthodox Christians (68.0%), unmarried (60.9%), employed (75.7%), educated (53.7%) and high-earned (59.4%) people. Majority of them initiated by peer pressure (34.4%) for academic good performance (24.1%) and continued the practice for entertainment (24.6%) and alertness purpose (24.3%). Just m...
Some easily applicable analytical methods were explored to evaluate the quality of personal care ... more Some easily applicable analytical methods were explored to evaluate the quality of personal care products containing aloe leaf gel. Aloins should be absent in these products in view of their side effects. To check this, liquid chromatography (LC) was applied.
Background: Type 2 diabetes is the predominant form of diabetes with increasing prevalence all ov... more Background: Type 2 diabetes is the predominant form of diabetes with increasing prevalence all over the world. Inadequate glycemic control in type 2 diabetic patients contributes to increased rates of macrovascular and microvascular diabetic complications. Objective: This study was conducted to determine the factors associated with poorly controlled type 2 diabetes. Methods: The institution-based cross-sectional study was conducted among type 2 diabetic patients investigated at Ayder Referral Hospital, Mekelle town, Ethiopia in February 2015. Patients were studied consecutively. Data were collected through interview using structured questionnaires and data collection form to extract data from patients medical records. Data were analyzed using SPSS version 20.0. Results: Of the total 384 patients, 48.7% had HbA1c ≥7%, indicating poor glycemic control. In the multivariate model, being under age 60 (<50 years: OR = 2.99, 95% CI 1.20-7.4; 50-59 years: OR = 4.7, 95% CI 2.0-11.0) and h...
A precise and reliable reversed-phase high-performance liquid chromatographic method with ultravi... more A precise and reliable reversed-phase high-performance liquid chromatographic method with ultraviolet detection was developed and validated to determine cinitapride in human plasma. After liquid-liquid extraction, chromatographic separation was achieved on a Nucleosil C18 (25 cm × 4.6 mm, 5 µm) column with an isocratic elution consisting of 10 mM ammonium acetate (pH 5.2), methanol, and acetonitrile, 40 : 50 : 10, v/v/v. The developed method was validated as per US FDA guidelines for its linearity, selectivity, sensitivity, precision, accuracy, and stability. Satisfactory findings were obtained from the validation studies. The linearity range of the method was 1 to 35 ng/mL while the extraction recovery of cinitapride in human plasma was more than 86%. The percent coefficient of variation of both intraday and interday precision was ≤7.1%.
This study aimed at determination of heavy metals (cadmium, lead, and zinc) in milk-based infant ... more This study aimed at determination of heavy metals (cadmium, lead, and zinc) in milk-based infant formulas collected from Mekelle, Ethiopia, and their associated health risks to the infants through consumption of these products. The infant feeding samples were dry-ashed in a muffle furnace followed by digestion in nitric acid and the resulting solutions were analyzed by flame atomic absorption spectrophotometer. Cadmium was not detected in the samples while the levels of lead and zinc ranged from not detected value to 0.103 mg/kg and from 27.888 to 71.553 mg/kg, respectively. The estimated daily intake values and the health risk indices of both metals were below their respective safety limits and the threshold of 1, respectively. These findings show low infant health risk of these metals through consumption of these products. Nevertheless, regular monitoring of infant formula for toxic metals is required since infants are potentially more susceptible to metals.
Evidence-Based Complementary and Alternative Medicine
Background. The highest prevalence and emergence of microbial infections coupled with the threat ... more Background. The highest prevalence and emergence of microbial infections coupled with the threat of antimicrobial resistance constitute a global concern, which entails searching for novel antimicrobial agents. Medicinal plants are among the major sources of medicines for novel drug discovery. Aloe adigratana is one of the endemic Aloe species in Ethiopia where the leaf latex of the plant is traditionally used for the treatment of various pathogenic conditions such as wound, dandruff, malaria, and diabetes. In spite of such claims, there was no scientific study done so far. The aim of the current study was, therefore, to evaluate the antimicrobial effect of leaf latex of A. adigratana and its thin layer chromatography (TLC) fractions. Methods. Thin layer chromatography (TLC) separation was employed for isolation of bioactive compounds. Agar well diffusion and microdilution assay method were used to evaluate the antimicrobial actions of the leaf latex and TLC fractions against six bac...
Advances in Pharmacological and Pharmaceutical Sciences
The treatment of type II DM involves the use of combination of drugs, especially at the chronic s... more The treatment of type II DM involves the use of combination of drugs, especially at the chronic stage. However, the pill burden of this combination therapy combined with swallowing difficulties, occurring at a later stage of DM, has been the major challenge for successful treatment outcomes. This study was aimed at formulating and optimizing a monolithic fixed-dose combination (FDC) of metformin (MET) and glibenclamide (GLB) orodispersible tablets (ODTs) to overcome both the pill burden and swallowing problems. The FDC ODTs were prepared by the melt granulation technique using polyethylene glycol (PEG) 6000 as a binding agent and crospovidone as a superdisintegrant. In the preliminary study, the effects of sodium lauryl sulphate (SLS), PEG 6000, crospovidone, and compression force on friability, disintegration time, and drug release of tablets were investigated. The FT-IR studies showed that there were no incompatibilities between MET and GLB as well as within excipients. The prelim...
A simple extractive spectrophotometric technique has been developed and validated for the determi... more A simple extractive spectrophotometric technique has been developed and validated for the determination of miconazole nitrate in pure and pharmaceutical formulations. The method is based on the formation of a chloroform-soluble ion-pair complex between the drug and bromocresol green (BCG) dye in an acidic medium. The complex showed absorption maxima at 422 nm, and the system obeys Beer’s law in the concentration range of 1–30 µg/mL with molar absorptivity of 2.285 × 104 L/mol/cm. The composition of the complex was studied by Job’s method of continuous variation, and the results revealed that the mole ratio of drug : BCG is 1 : 1. Full factorial design was used to optimize the effect of variable factors, and the method was validated based on the ICH guidelines. The method was applied for the determination of miconazole nitrate in real samples.
A multiple headspace extraction experiment coupled to gas chromatography (MHE-GC) is used for the... more A multiple headspace extraction experiment coupled to gas chromatography (MHE-GC) is used for the classification and qualification of different mesoporous silica (MPSi) materials used for drug delivery. In this MHE experiment, a pure liquid solvent probe is fully evaporated in a sealed headspace vial in the presence of the MPSi sample, leading to a gas-solid partitioning that is theoretically described. The obtained results matched with the known characteristics of the studied samples, such as adsorption capacity due to differences in porosity and passivation treatments. Moreover, it proves the effectiveness of a poly dimethyl siloxane (PDMS) coating treatment over a thermal one in reducing the specific interactions of the MPSi. In addition, it evidences the important role of confinement effects when the pore diameter is close to the microporosity range. Finally, a simple experiment for fast screening is proposed by comparison of the results obtained for four different probes used as a mixture.
HighlightsOff‐line and on‐line CE methods for the study of aldehyde oxidase with phthalazine.Opti... more HighlightsOff‐line and on‐line CE methods for the study of aldehyde oxidase with phthalazine.Optimization and validation of the incubation and separation methods.First TDLFP on‐line study of aldehyde oxidase with phthalazine.Easy, economical, time saving and eco‐friendly on‐line CE method. Abstract An optimized and economical capillary electrophoretic method for both off‐line and on‐line study of the enzyme aldehyde oxidase and its substrate phthalazine was developed. The separation of the substrate phthalazine and its metabolite 1‐phthalazinone was achieved using micellar electrokinetic chromatography (MEKC) with sodium dodecyl sulphate in the background electrolyte (BGE). The BGE consists of 25 mM sodium phosphate buffer containing 50 mM sodium dodecyl sulphate at pH 7.4. A bare‐fused‐silica capillary with a capillary length of 40 cm, 50 &mgr;m ID and effective length of 30 cm was used to develop the capillary electrophoresis method. Improved separation conditions were elaborated and the separation method was validated based on the ICH and EMA guidelines. The limit of detection for phthalazine and 1‐phthalazinone was 8 &mgr;M and 3 &mgr;M, respectively. The limit of quantification was 25 &mgr;M for phthalazine and 10 &mgr;M for 1‐phthalazinone. The linearity of the detector response was checked for 1‐phthalazinone at nine different concentrations in the range 10–500 &mgr;M and the determination coefficient was 0.9994. Accuracy was tested by comparing the corrected peak area of 1‐phthalazinone reference solution at 20 &mgr;M and 50 &mgr;M with the corrected peak area of 20 &mgr;M and 50 &mgr;M 1‐phthalazinone in the presence of human liver cytosol (HLC). Accuracy values of +5.3% and ‐2.5% were obtained at 20 &mgr;M and 50 &mgr;M, respectively. The on‐line enzymatic reaction was successful with the application of the method of transverse diffusion of laminar flow profiles (TDLFP), which enables the mixing as well as separation of the enzyme and substrate inside the nanoliter‐scale capillary. TDLFP is examined to be precise when performing 5 consecutive injections, with a relative standard deviation of 7.16% which is within the limitation of EMA standards. This miniaturized and low‐cost incubation and separation method could be further introduced into industry and extended to other substrates.
Journal of pharmaceutical and biomedical analysis, Jan 31, 2017
This article describes the development and validation of a liquid chromatographic method for spir... more This article describes the development and validation of a liquid chromatographic method for spiramycin using a column with superficially porous particles. Gradient elution was applied and the mobile phase consisted of phosphate buffer (0.2M; pH 8.3) - H2O - acetonitrile in a ratio 10:60:30 (v/v/v) for mobile phase A and 10:30:60 (v/v/v) for mobile phase B. UV detection was performed at 232nm. Compared to previous methods, the analysis time was about two times faster and impurities were better separated. Furthermore, impurities which were present above 0.25% were characterized using liquid chromatography coupled with mass spectrometry (LC/MS).
Journal of pharmaceutical and biomedical analysis, Jan 2, 2015
Misoprostol is a synthetic prostaglandin E1 analogue which is mainly used for prevention and trea... more Misoprostol is a synthetic prostaglandin E1 analogue which is mainly used for prevention and treatment of gastric ulcers, but also for abortion due to its labour inducing effect. Misoprostol exists as a mixture of diastereoisomers (1:1) and has several related impurities owing to its instability at higher temperatures and moisture. A simple and robust reversed phase liquid chromatographic (RPLC) method is described for the separation of the related substances and a normal phase (NP) LC method for the separation of misoprostol diastereoisomers. The RPLC method was performed using an Ascentis Express C18 (150mm×4.6mm, 5μm) column kept at 35°C. The mobile phase was a gradient mixture of mobile phase A (ACN-H2O-MeOH, 28:69:3 v/v/v) and mobile phase B (ACN-H2O-MeOH, 47:50:3 v/v/v) eluted at a flow rate of 1.5mL/min. UV detection was performed at 200nm. The NPLC method was undertaken by using an XBridge bare silica (150mm×2.1mm, 3.5μm) column at 35°C. The mobile phase contained 1-propanol...
Aloe leaf latex is a commonly used plant preparation in traditional medicine. However, quality co... more Aloe leaf latex is a commonly used plant preparation in traditional medicine. However, quality control on the content of medicinally important constituents is often limited. Hence, establishing a reliable quality control method to identify and quantify bioactive markers is important to ensure safety and efficacy. In the present study, a novel liquid chromatographic (LC) method was developed and validated for efficient analysis of bioactive markers to evaluate the quality of aloe leaf latex. Quantification of marker compounds was possible in only 7 min on a monolithic column using gradient elution with 0.1 % formic acid in acetonitrile and water as mobile phases. The major compounds (aloins A and B) could be baseline separated together with related compounds within 10 min. The method showed excellent linearity with determination coefficients (r2) of 0.9999. Detection limits were 0.017 and 0.013 μg/mL, while quantification limits were 0.057 and 0.043 μg/mL for aloin A and aloin B, respectively. Relative standard deviation (RSD) values for intra- and inter-day precision were less than 2% and recoveries for both aloins were close to 100 %. The robustness was evaluated using an experimental design. The method was applied to some aloe leaf latex samples from Ethiopia. Aloin contents varied from 14 to 35 % and two unknown peaks were tentatively identified as aloinoside and microdontin.
Background: Khat chewing practice has increased over the years and chronic khat use is associated... more Background: Khat chewing practice has increased over the years and chronic khat use is associated with adverse health and socio-economic effects. Thus, this study was undertaken among khat chewers in Mekelle town, northern Ethiopia to investigate socio-economic and health-related effects of khat chewing. Methods: A cross-sectional study was conducted in Mekelle from April to May 2016 with the help of a structured questionnaire to collect data. Simple random sampling method was used to select the respondents. Descriptive statistics were employed for summarization and presentation of data. Results: Khat chewing was most commonly practiced among male gender (87.1%), productive age group (94.7%), Orthodox Christians (68.0%), unmarried (60.9%), employed (75.7%), educated (53.7%) and high-earned (59.4%) people. Majority of them initiated by peer pressure (34.4%) for academic good performance (24.1%) and continued the practice for entertainment (24.6%) and alertness purpose (24.3%). Just m...
Some easily applicable analytical methods were explored to evaluate the quality of personal care ... more Some easily applicable analytical methods were explored to evaluate the quality of personal care products containing aloe leaf gel. Aloins should be absent in these products in view of their side effects. To check this, liquid chromatography (LC) was applied.
Background: Type 2 diabetes is the predominant form of diabetes with increasing prevalence all ov... more Background: Type 2 diabetes is the predominant form of diabetes with increasing prevalence all over the world. Inadequate glycemic control in type 2 diabetic patients contributes to increased rates of macrovascular and microvascular diabetic complications. Objective: This study was conducted to determine the factors associated with poorly controlled type 2 diabetes. Methods: The institution-based cross-sectional study was conducted among type 2 diabetic patients investigated at Ayder Referral Hospital, Mekelle town, Ethiopia in February 2015. Patients were studied consecutively. Data were collected through interview using structured questionnaires and data collection form to extract data from patients medical records. Data were analyzed using SPSS version 20.0. Results: Of the total 384 patients, 48.7% had HbA1c ≥7%, indicating poor glycemic control. In the multivariate model, being under age 60 (<50 years: OR = 2.99, 95% CI 1.20-7.4; 50-59 years: OR = 4.7, 95% CI 2.0-11.0) and h...
A precise and reliable reversed-phase high-performance liquid chromatographic method with ultravi... more A precise and reliable reversed-phase high-performance liquid chromatographic method with ultraviolet detection was developed and validated to determine cinitapride in human plasma. After liquid-liquid extraction, chromatographic separation was achieved on a Nucleosil C18 (25 cm × 4.6 mm, 5 µm) column with an isocratic elution consisting of 10 mM ammonium acetate (pH 5.2), methanol, and acetonitrile, 40 : 50 : 10, v/v/v. The developed method was validated as per US FDA guidelines for its linearity, selectivity, sensitivity, precision, accuracy, and stability. Satisfactory findings were obtained from the validation studies. The linearity range of the method was 1 to 35 ng/mL while the extraction recovery of cinitapride in human plasma was more than 86%. The percent coefficient of variation of both intraday and interday precision was ≤7.1%.
This study aimed at determination of heavy metals (cadmium, lead, and zinc) in milk-based infant ... more This study aimed at determination of heavy metals (cadmium, lead, and zinc) in milk-based infant formulas collected from Mekelle, Ethiopia, and their associated health risks to the infants through consumption of these products. The infant feeding samples were dry-ashed in a muffle furnace followed by digestion in nitric acid and the resulting solutions were analyzed by flame atomic absorption spectrophotometer. Cadmium was not detected in the samples while the levels of lead and zinc ranged from not detected value to 0.103 mg/kg and from 27.888 to 71.553 mg/kg, respectively. The estimated daily intake values and the health risk indices of both metals were below their respective safety limits and the threshold of 1, respectively. These findings show low infant health risk of these metals through consumption of these products. Nevertheless, regular monitoring of infant formula for toxic metals is required since infants are potentially more susceptible to metals.
Evidence-Based Complementary and Alternative Medicine
Background. The highest prevalence and emergence of microbial infections coupled with the threat ... more Background. The highest prevalence and emergence of microbial infections coupled with the threat of antimicrobial resistance constitute a global concern, which entails searching for novel antimicrobial agents. Medicinal plants are among the major sources of medicines for novel drug discovery. Aloe adigratana is one of the endemic Aloe species in Ethiopia where the leaf latex of the plant is traditionally used for the treatment of various pathogenic conditions such as wound, dandruff, malaria, and diabetes. In spite of such claims, there was no scientific study done so far. The aim of the current study was, therefore, to evaluate the antimicrobial effect of leaf latex of A. adigratana and its thin layer chromatography (TLC) fractions. Methods. Thin layer chromatography (TLC) separation was employed for isolation of bioactive compounds. Agar well diffusion and microdilution assay method were used to evaluate the antimicrobial actions of the leaf latex and TLC fractions against six bac...
Advances in Pharmacological and Pharmaceutical Sciences
The treatment of type II DM involves the use of combination of drugs, especially at the chronic s... more The treatment of type II DM involves the use of combination of drugs, especially at the chronic stage. However, the pill burden of this combination therapy combined with swallowing difficulties, occurring at a later stage of DM, has been the major challenge for successful treatment outcomes. This study was aimed at formulating and optimizing a monolithic fixed-dose combination (FDC) of metformin (MET) and glibenclamide (GLB) orodispersible tablets (ODTs) to overcome both the pill burden and swallowing problems. The FDC ODTs were prepared by the melt granulation technique using polyethylene glycol (PEG) 6000 as a binding agent and crospovidone as a superdisintegrant. In the preliminary study, the effects of sodium lauryl sulphate (SLS), PEG 6000, crospovidone, and compression force on friability, disintegration time, and drug release of tablets were investigated. The FT-IR studies showed that there were no incompatibilities between MET and GLB as well as within excipients. The prelim...
A simple extractive spectrophotometric technique has been developed and validated for the determi... more A simple extractive spectrophotometric technique has been developed and validated for the determination of miconazole nitrate in pure and pharmaceutical formulations. The method is based on the formation of a chloroform-soluble ion-pair complex between the drug and bromocresol green (BCG) dye in an acidic medium. The complex showed absorption maxima at 422 nm, and the system obeys Beer’s law in the concentration range of 1–30 µg/mL with molar absorptivity of 2.285 × 104 L/mol/cm. The composition of the complex was studied by Job’s method of continuous variation, and the results revealed that the mole ratio of drug : BCG is 1 : 1. Full factorial design was used to optimize the effect of variable factors, and the method was validated based on the ICH guidelines. The method was applied for the determination of miconazole nitrate in real samples.
A multiple headspace extraction experiment coupled to gas chromatography (MHE-GC) is used for the... more A multiple headspace extraction experiment coupled to gas chromatography (MHE-GC) is used for the classification and qualification of different mesoporous silica (MPSi) materials used for drug delivery. In this MHE experiment, a pure liquid solvent probe is fully evaporated in a sealed headspace vial in the presence of the MPSi sample, leading to a gas-solid partitioning that is theoretically described. The obtained results matched with the known characteristics of the studied samples, such as adsorption capacity due to differences in porosity and passivation treatments. Moreover, it proves the effectiveness of a poly dimethyl siloxane (PDMS) coating treatment over a thermal one in reducing the specific interactions of the MPSi. In addition, it evidences the important role of confinement effects when the pore diameter is close to the microporosity range. Finally, a simple experiment for fast screening is proposed by comparison of the results obtained for four different probes used as a mixture.
HighlightsOff‐line and on‐line CE methods for the study of aldehyde oxidase with phthalazine.Opti... more HighlightsOff‐line and on‐line CE methods for the study of aldehyde oxidase with phthalazine.Optimization and validation of the incubation and separation methods.First TDLFP on‐line study of aldehyde oxidase with phthalazine.Easy, economical, time saving and eco‐friendly on‐line CE method. Abstract An optimized and economical capillary electrophoretic method for both off‐line and on‐line study of the enzyme aldehyde oxidase and its substrate phthalazine was developed. The separation of the substrate phthalazine and its metabolite 1‐phthalazinone was achieved using micellar electrokinetic chromatography (MEKC) with sodium dodecyl sulphate in the background electrolyte (BGE). The BGE consists of 25 mM sodium phosphate buffer containing 50 mM sodium dodecyl sulphate at pH 7.4. A bare‐fused‐silica capillary with a capillary length of 40 cm, 50 &mgr;m ID and effective length of 30 cm was used to develop the capillary electrophoresis method. Improved separation conditions were elaborated and the separation method was validated based on the ICH and EMA guidelines. The limit of detection for phthalazine and 1‐phthalazinone was 8 &mgr;M and 3 &mgr;M, respectively. The limit of quantification was 25 &mgr;M for phthalazine and 10 &mgr;M for 1‐phthalazinone. The linearity of the detector response was checked for 1‐phthalazinone at nine different concentrations in the range 10–500 &mgr;M and the determination coefficient was 0.9994. Accuracy was tested by comparing the corrected peak area of 1‐phthalazinone reference solution at 20 &mgr;M and 50 &mgr;M with the corrected peak area of 20 &mgr;M and 50 &mgr;M 1‐phthalazinone in the presence of human liver cytosol (HLC). Accuracy values of +5.3% and ‐2.5% were obtained at 20 &mgr;M and 50 &mgr;M, respectively. The on‐line enzymatic reaction was successful with the application of the method of transverse diffusion of laminar flow profiles (TDLFP), which enables the mixing as well as separation of the enzyme and substrate inside the nanoliter‐scale capillary. TDLFP is examined to be precise when performing 5 consecutive injections, with a relative standard deviation of 7.16% which is within the limitation of EMA standards. This miniaturized and low‐cost incubation and separation method could be further introduced into industry and extended to other substrates.
Journal of pharmaceutical and biomedical analysis, Jan 31, 2017
This article describes the development and validation of a liquid chromatographic method for spir... more This article describes the development and validation of a liquid chromatographic method for spiramycin using a column with superficially porous particles. Gradient elution was applied and the mobile phase consisted of phosphate buffer (0.2M; pH 8.3) - H2O - acetonitrile in a ratio 10:60:30 (v/v/v) for mobile phase A and 10:30:60 (v/v/v) for mobile phase B. UV detection was performed at 232nm. Compared to previous methods, the analysis time was about two times faster and impurities were better separated. Furthermore, impurities which were present above 0.25% were characterized using liquid chromatography coupled with mass spectrometry (LC/MS).
Journal of pharmaceutical and biomedical analysis, Jan 2, 2015
Misoprostol is a synthetic prostaglandin E1 analogue which is mainly used for prevention and trea... more Misoprostol is a synthetic prostaglandin E1 analogue which is mainly used for prevention and treatment of gastric ulcers, but also for abortion due to its labour inducing effect. Misoprostol exists as a mixture of diastereoisomers (1:1) and has several related impurities owing to its instability at higher temperatures and moisture. A simple and robust reversed phase liquid chromatographic (RPLC) method is described for the separation of the related substances and a normal phase (NP) LC method for the separation of misoprostol diastereoisomers. The RPLC method was performed using an Ascentis Express C18 (150mm×4.6mm, 5μm) column kept at 35°C. The mobile phase was a gradient mixture of mobile phase A (ACN-H2O-MeOH, 28:69:3 v/v/v) and mobile phase B (ACN-H2O-MeOH, 47:50:3 v/v/v) eluted at a flow rate of 1.5mL/min. UV detection was performed at 200nm. The NPLC method was undertaken by using an XBridge bare silica (150mm×2.1mm, 3.5μm) column at 35°C. The mobile phase contained 1-propanol...
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