A stability-indicating reversed-phase high-performance liquid chromatography method using a photo... more A stability-indicating reversed-phase high-performance liquid chromatography method using a photodiode array detector has been developed for simultaneous estimation of chlorthalidone (CLR) and azilsartan medoxomil (AZL) in combined solid dosage form. The method was developed based on statistical design of experiments (DoE) followed by optimization using the response surface methodology. Separation was achieved on a double end-capped C18 column (150 mm × 4 mm, 5 μm). The effects of % acetonitrile (v/v) and buffer salt concentrations on the retention time of the two drugs and on their resolution were investigated and optimized. A robust design space was created by the overlay contour plot method. The optimum chromatographic condition within the design space was found to be isocratic mobile phase consisting of 10 mM Tris(hydroxymethyl)aminomethane buffer (pH 7.7) and acetonitrile at ratio of 60:40 (v/v) with flow rate of 1 mL min−1 for 7 min. The retention times of CLR and AZL were found to be 2.6 and 4.9 min, respectively. The method was validated according to International Conference on Harmonization (ICH) and Food and Drug Administration (FDA) guidelines, and various validation parameters were determined. Forced degradation studies were also carried out in acid, base, oxidation, and reduction media with a view to establishing the specificity and stability-indicating property. The practical applicability of the method was confirmed by determining CLR and AZL in combined dosage form. This reliable and validated stability-indicating method for simultaneous estimation of CLR and AZL is available for routine analysis in the pharmaceutical industry as well as research laboratories.
A stability-indicating reversed-phase high-performance
liquid chromatography method using a photo... more A stability-indicating reversed-phase high-performance liquid chromatography method using a photodiode array detector has been developed for simultaneous estimation of chlorthalidone (CLR) and azilsartan medoxomil (AZL) in combined solid dosage form. The method was developed based on statistical design of experiments (DoE) followed by optimization using the response surface methodology. Separation was achieved on a double end-capped C18 column (150 mm × 4 mm, 5 μm). The effects of % acetonitrile (v/v) and buffer salt concentrations on the retention time of the two drugs and on their resolution were investigated and optimized. A robust design space was created by the overlay contour plot method. The optimum chromatographic condition within the design space was found to be isocratic mobile phase consisting of 10 mM Tris(hydroxymethyl)aminomethane buffer (pH 7.7) and acetonitrile at ratio of 60:40 (v/v) with flow rate of 1 mL min−1 for 7 min. The retention times of CLR and AZL were found to be 2.6 and 4.9 min, respectively. The method was validated according to International Conference on Harmonization (ICH) and Food and Drug Administration (FDA) guidelines, and various validation parameters were determined. Forced degradation studies were also carried out in acid, base, oxidation, and reduction media with a view to establishing the specificity and stability-indicating property. The practical applicability of the method was confirmed by determining CLR and AZL in combined dosage form. This reliable and validated stability-indicating method for simultaneous estimation of CLR and AZL is available for routine analysis in the pharmaceutical industry as well as research laboratories.
A simple RP-HPLC method has been developed for simultaneous estimation of fexofenadine and pseudo... more A simple RP-HPLC method has been developed for simultaneous estimation of fexofenadine and pseudoephedrine in their extended release tablet. The method was developed based on statistical design of experiments (DoE) and Response Surface Methodology. Separation was achieved on double end-capped C 18 column (250 mm × 4 mm, 5 í µí¼m). In this experiment, two components of mobile phase, namely, acetonitrile (% v/v) and methanol (% v/v), were the factors whereas retention and resolution of the chromatographic peaks were the responses. The effects of different composition of factors on the corresponding responses were investigated. The optimum chromatographic condition for the current case was found as an isocratic mobile phase consisting of 20 mM phosphate buffer (pH 6.8) and acetonitrile and methanol in a ratio of 50 : 36 : 14 (% v/v) at a flow rate of 1 mL/min for 7 minutes. The retention of pseudoephedrine and fexofenadine was found to be 2.6 min and 4.7 min, respectively. The method was validated according to the ICH and FDA guidelines and various validation parameters were determined. Also, forced degradation studies in acid, base, oxidation, and reduction media and in thermal condition were performed to establish specificity and stability-indicating property of this method. Practical applicability of this method was checked in extended release tablets available in Bangladeshi market.
A rapid, sensitive and stability indicating ion-pair reversed-phase high-performance liquid chrom... more A rapid, sensitive and stability indicating ion-pair reversed-phase high-performance liquid chromatographic method was developed for simultaneous estimation of naproxen (NPX) and esomeprazole (ESP) in pharmaceutical preparations. In our study, this new method was used to overcome the instability problem of ESP during high-performance liquid chromatographic analysis in the presence of acidic drugs such as NPX. The method was validated according to ICH, FDA and USP guidelines with respect to accuracy, precision, specif-icity, linearity, solution stability, robustness, sensitivity and system suitability. The method was developed by using an isocratic condition of mobile phase comprising buffer [tetrabutylammonium hydroxide (0.0077 M) and n-heptane sulfonic acid –Na salt (0.002 M), pH 7.6], acetonitrile and methanol in a 60 : 20 : 20 v/v/v ratio at a flow rate of 1.5 mL/min over a C-18 (Octadecyl-silica, 5 mm, 250 3 4.6 mm) column at ambient temperature. The recovery for both drugs was found to be >99% which demonstrated the accuracy of this method. Intra-and inter-day precision studies of the new method were less than the maximum allowable limit [% relative standard deviation (RSD) 2.0 according to FDA]. The method showed linear response with a correlation coefficient (r 2) value of 0.999 for both drugs. More importantly, ESP was quite stable in diluting solvent and mobile phase in the presence of NPX for >3 days. Therefore, it was found to be an accurate, reproducible, sensitive and highly stability-indicating method and can be successfully applied for routine analysis of simultaneous assay of NPX and ESP in pharmaceutical dosage forms.
The aim of our current research was to synthesize some transition metal complexes of Naproxen, de... more The aim of our current research was to synthesize some transition metal complexes of Naproxen, determine their physical properties, and examine their relative stability under various conditions. Characterizations of these complexes were done by 1H-NMR, Differential Scanning Calorimetry (DSC), FT-IR, HPLC, and scanning electron microscope (SEM). Complexes were subjected to acidic, basic, and aqueous hydrolysis as well as oxidation, reduction, and thermal degradation. Also the reversed phase high-performance liquid chromatography (RP-HPLC) method of Naproxen outlined in USP was verified for the Naproxen-metal complexes, with respect to accuracy, precision, solution stability, robustness, and system suitability. The melting points of the complexes were higher than that of the parent drug molecule suggesting their thermal stability. In forced degradation study, complexes were found more stable than the Naproxen itself in all conditions: acidic, basic, oxidation, and reduction media. All the HPLC verification parameters were found within the acceptable value. Therefore, it can be concluded from the study that the metal complexes of Naproxen can be more stable drug entity and offer better efficacy and longer shelf life than the parent Naproxen.
A rapid and stability-indicating reversed phase high-performance liquid chromatography (RP-HPLC) ... more A rapid and stability-indicating reversed phase high-performance liquid chromatography (RP-HPLC) method was developed for simultaneous quantification of paracetamol and ibuprofen in their combined dosage form especially to get some more advantages over other methods already developed for this combination. The method was validated according to United States Pharmacopeia (USP) guideline with respect to accuracy, precision, specificity, linearity, solution stability, robustness, sensitivity, and system suitability. Forced degradation study was validated according to International Conference on Harmonisation (ICH). For this, an isocratic condition of mobile phase comprising phosphate buffer (pH 6.8) and acetonitrile in a ratio of 65:35, v/v at a flow rate of 0.7 mL/minute over RP C18 (octadecylsilane (ODS), 150 × 4.6 mm, 5 μm, Phenomenex Inc.) column at ambient temperature was maintained. The method showed excellent linear response with correlation coefficient (R2) values of 0.999 and 1.0 for paracetamol and ibuprofen respectively, which were within the limit of correlation coefficient (R2 0.995). The percent recoveries for two drugs were found within the acceptance limit of (97.0–103.0%). Intraand inter-day precision studies of the new method were less than the maximum allowable limit percentage of relative standard deviation (%RSD) 2.0. Forced degradation of the drug product was carried out as per the ICH guidelines with a view to establishing the stability-indicating property of this method and providing useful information about the degradation pathways, degradation products, and how the quality of a drug substance and drug product changes with time under the influence of various stressing conditions. The degradation of ibuprofen was within the limit (5–20%, according to the guideline of ICH), while paracetamol showed 20% degradation in oxidation and basic condition.
A stability-indicating reversed-phase high-performance liquid chromatography method using a photo... more A stability-indicating reversed-phase high-performance liquid chromatography method using a photodiode array detector has been developed for simultaneous estimation of chlorthalidone (CLR) and azilsartan medoxomil (AZL) in combined solid dosage form. The method was developed based on statistical design of experiments (DoE) followed by optimization using the response surface methodology. Separation was achieved on a double end-capped C18 column (150 mm × 4 mm, 5 μm). The effects of % acetonitrile (v/v) and buffer salt concentrations on the retention time of the two drugs and on their resolution were investigated and optimized. A robust design space was created by the overlay contour plot method. The optimum chromatographic condition within the design space was found to be isocratic mobile phase consisting of 10 mM Tris(hydroxymethyl)aminomethane buffer (pH 7.7) and acetonitrile at ratio of 60:40 (v/v) with flow rate of 1 mL min−1 for 7 min. The retention times of CLR and AZL were found to be 2.6 and 4.9 min, respectively. The method was validated according to International Conference on Harmonization (ICH) and Food and Drug Administration (FDA) guidelines, and various validation parameters were determined. Forced degradation studies were also carried out in acid, base, oxidation, and reduction media with a view to establishing the specificity and stability-indicating property. The practical applicability of the method was confirmed by determining CLR and AZL in combined dosage form. This reliable and validated stability-indicating method for simultaneous estimation of CLR and AZL is available for routine analysis in the pharmaceutical industry as well as research laboratories.
A stability-indicating reversed-phase high-performance
liquid chromatography method using a photo... more A stability-indicating reversed-phase high-performance liquid chromatography method using a photodiode array detector has been developed for simultaneous estimation of chlorthalidone (CLR) and azilsartan medoxomil (AZL) in combined solid dosage form. The method was developed based on statistical design of experiments (DoE) followed by optimization using the response surface methodology. Separation was achieved on a double end-capped C18 column (150 mm × 4 mm, 5 μm). The effects of % acetonitrile (v/v) and buffer salt concentrations on the retention time of the two drugs and on their resolution were investigated and optimized. A robust design space was created by the overlay contour plot method. The optimum chromatographic condition within the design space was found to be isocratic mobile phase consisting of 10 mM Tris(hydroxymethyl)aminomethane buffer (pH 7.7) and acetonitrile at ratio of 60:40 (v/v) with flow rate of 1 mL min−1 for 7 min. The retention times of CLR and AZL were found to be 2.6 and 4.9 min, respectively. The method was validated according to International Conference on Harmonization (ICH) and Food and Drug Administration (FDA) guidelines, and various validation parameters were determined. Forced degradation studies were also carried out in acid, base, oxidation, and reduction media with a view to establishing the specificity and stability-indicating property. The practical applicability of the method was confirmed by determining CLR and AZL in combined dosage form. This reliable and validated stability-indicating method for simultaneous estimation of CLR and AZL is available for routine analysis in the pharmaceutical industry as well as research laboratories.
A simple RP-HPLC method has been developed for simultaneous estimation of fexofenadine and pseudo... more A simple RP-HPLC method has been developed for simultaneous estimation of fexofenadine and pseudoephedrine in their extended release tablet. The method was developed based on statistical design of experiments (DoE) and Response Surface Methodology. Separation was achieved on double end-capped C 18 column (250 mm × 4 mm, 5 í µí¼m). In this experiment, two components of mobile phase, namely, acetonitrile (% v/v) and methanol (% v/v), were the factors whereas retention and resolution of the chromatographic peaks were the responses. The effects of different composition of factors on the corresponding responses were investigated. The optimum chromatographic condition for the current case was found as an isocratic mobile phase consisting of 20 mM phosphate buffer (pH 6.8) and acetonitrile and methanol in a ratio of 50 : 36 : 14 (% v/v) at a flow rate of 1 mL/min for 7 minutes. The retention of pseudoephedrine and fexofenadine was found to be 2.6 min and 4.7 min, respectively. The method was validated according to the ICH and FDA guidelines and various validation parameters were determined. Also, forced degradation studies in acid, base, oxidation, and reduction media and in thermal condition were performed to establish specificity and stability-indicating property of this method. Practical applicability of this method was checked in extended release tablets available in Bangladeshi market.
A rapid, sensitive and stability indicating ion-pair reversed-phase high-performance liquid chrom... more A rapid, sensitive and stability indicating ion-pair reversed-phase high-performance liquid chromatographic method was developed for simultaneous estimation of naproxen (NPX) and esomeprazole (ESP) in pharmaceutical preparations. In our study, this new method was used to overcome the instability problem of ESP during high-performance liquid chromatographic analysis in the presence of acidic drugs such as NPX. The method was validated according to ICH, FDA and USP guidelines with respect to accuracy, precision, specif-icity, linearity, solution stability, robustness, sensitivity and system suitability. The method was developed by using an isocratic condition of mobile phase comprising buffer [tetrabutylammonium hydroxide (0.0077 M) and n-heptane sulfonic acid –Na salt (0.002 M), pH 7.6], acetonitrile and methanol in a 60 : 20 : 20 v/v/v ratio at a flow rate of 1.5 mL/min over a C-18 (Octadecyl-silica, 5 mm, 250 3 4.6 mm) column at ambient temperature. The recovery for both drugs was found to be >99% which demonstrated the accuracy of this method. Intra-and inter-day precision studies of the new method were less than the maximum allowable limit [% relative standard deviation (RSD) 2.0 according to FDA]. The method showed linear response with a correlation coefficient (r 2) value of 0.999 for both drugs. More importantly, ESP was quite stable in diluting solvent and mobile phase in the presence of NPX for >3 days. Therefore, it was found to be an accurate, reproducible, sensitive and highly stability-indicating method and can be successfully applied for routine analysis of simultaneous assay of NPX and ESP in pharmaceutical dosage forms.
The aim of our current research was to synthesize some transition metal complexes of Naproxen, de... more The aim of our current research was to synthesize some transition metal complexes of Naproxen, determine their physical properties, and examine their relative stability under various conditions. Characterizations of these complexes were done by 1H-NMR, Differential Scanning Calorimetry (DSC), FT-IR, HPLC, and scanning electron microscope (SEM). Complexes were subjected to acidic, basic, and aqueous hydrolysis as well as oxidation, reduction, and thermal degradation. Also the reversed phase high-performance liquid chromatography (RP-HPLC) method of Naproxen outlined in USP was verified for the Naproxen-metal complexes, with respect to accuracy, precision, solution stability, robustness, and system suitability. The melting points of the complexes were higher than that of the parent drug molecule suggesting their thermal stability. In forced degradation study, complexes were found more stable than the Naproxen itself in all conditions: acidic, basic, oxidation, and reduction media. All the HPLC verification parameters were found within the acceptable value. Therefore, it can be concluded from the study that the metal complexes of Naproxen can be more stable drug entity and offer better efficacy and longer shelf life than the parent Naproxen.
A rapid and stability-indicating reversed phase high-performance liquid chromatography (RP-HPLC) ... more A rapid and stability-indicating reversed phase high-performance liquid chromatography (RP-HPLC) method was developed for simultaneous quantification of paracetamol and ibuprofen in their combined dosage form especially to get some more advantages over other methods already developed for this combination. The method was validated according to United States Pharmacopeia (USP) guideline with respect to accuracy, precision, specificity, linearity, solution stability, robustness, sensitivity, and system suitability. Forced degradation study was validated according to International Conference on Harmonisation (ICH). For this, an isocratic condition of mobile phase comprising phosphate buffer (pH 6.8) and acetonitrile in a ratio of 65:35, v/v at a flow rate of 0.7 mL/minute over RP C18 (octadecylsilane (ODS), 150 × 4.6 mm, 5 μm, Phenomenex Inc.) column at ambient temperature was maintained. The method showed excellent linear response with correlation coefficient (R2) values of 0.999 and 1.0 for paracetamol and ibuprofen respectively, which were within the limit of correlation coefficient (R2 0.995). The percent recoveries for two drugs were found within the acceptance limit of (97.0–103.0%). Intraand inter-day precision studies of the new method were less than the maximum allowable limit percentage of relative standard deviation (%RSD) 2.0. Forced degradation of the drug product was carried out as per the ICH guidelines with a view to establishing the stability-indicating property of this method and providing useful information about the degradation pathways, degradation products, and how the quality of a drug substance and drug product changes with time under the influence of various stressing conditions. The degradation of ibuprofen was within the limit (5–20%, according to the guideline of ICH), while paracetamol showed 20% degradation in oxidation and basic condition.
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Papers by Ruhul Kayesh
liquid chromatography method using a photodiode
array detector has been developed for simultaneous
estimation of chlorthalidone (CLR) and azilsartan medoxomil
(AZL) in combined solid dosage form. The method
was developed based on statistical design of experiments
(DoE) followed by optimization using the response surface
methodology. Separation was achieved on a double
end-capped C18 column (150 mm × 4 mm, 5 μm). The
effects of % acetonitrile (v/v) and buffer salt concentrations
on the retention time of the two drugs and on their
resolution were investigated and optimized. A robust
design space was created by the overlay contour plot
method. The optimum chromatographic condition within
the design space was found to be isocratic mobile phase
consisting of 10 mM Tris(hydroxymethyl)aminomethane
buffer (pH 7.7) and acetonitrile at ratio of 60:40 (v/v)
with flow rate of 1 mL min−1 for 7 min. The retention
times of CLR and AZL were found to be 2.6 and 4.9 min,
respectively. The method was validated according to
International Conference on Harmonization (ICH) and
Food and Drug Administration (FDA) guidelines, and various
validation parameters were determined. Forced degradation
studies were also carried out in acid, base, oxidation,
and reduction media with a view to establishing the specificity and stability-indicating property. The practical
applicability of the method was confirmed by determining
CLR and AZL in combined dosage form. This reliable
and validated stability-indicating method for simultaneous
estimation of CLR and AZL is available for routine
analysis in the pharmaceutical industry as well as research
laboratories.
quantification of paracetamol and ibuprofen in their combined dosage form especially to get some more advantages over other methods already developed
for this combination. The method was validated according to United States Pharmacopeia (USP) guideline with respect to accuracy, precision, specificity,
linearity, solution stability, robustness, sensitivity, and system suitability. Forced degradation study was validated according to International Conference on
Harmonisation (ICH). For this, an isocratic condition of mobile phase comprising phosphate buffer (pH 6.8) and acetonitrile in a ratio of 65:35, v/v at a flow
rate of 0.7 mL/minute over RP C18 (octadecylsilane (ODS), 150 × 4.6 mm, 5 μm, Phenomenex Inc.) column at ambient temperature was maintained. The
method showed excellent linear response with correlation coefficient (R2) values of 0.999 and 1.0 for paracetamol and ibuprofen respectively, which were
within the limit of correlation coefficient (R2 0.995). The percent recoveries for two drugs were found within the acceptance limit of (97.0–103.0%). Intraand
inter-day precision studies of the new method were less than the maximum allowable limit percentage of relative standard deviation (%RSD) 2.0.
Forced degradation of the drug product was carried out as per the ICH guidelines with a view to establishing the stability-indicating property of this method
and providing useful information about the degradation pathways, degradation products, and how the quality of a drug substance and drug product changes
with time under the influence of various stressing conditions. The degradation of ibuprofen was within the limit (5–20%, according to the guideline of ICH),
while paracetamol showed 20% degradation in oxidation and basic condition.
liquid chromatography method using a photodiode
array detector has been developed for simultaneous
estimation of chlorthalidone (CLR) and azilsartan medoxomil
(AZL) in combined solid dosage form. The method
was developed based on statistical design of experiments
(DoE) followed by optimization using the response surface
methodology. Separation was achieved on a double
end-capped C18 column (150 mm × 4 mm, 5 μm). The
effects of % acetonitrile (v/v) and buffer salt concentrations
on the retention time of the two drugs and on their
resolution were investigated and optimized. A robust
design space was created by the overlay contour plot
method. The optimum chromatographic condition within
the design space was found to be isocratic mobile phase
consisting of 10 mM Tris(hydroxymethyl)aminomethane
buffer (pH 7.7) and acetonitrile at ratio of 60:40 (v/v)
with flow rate of 1 mL min−1 for 7 min. The retention
times of CLR and AZL were found to be 2.6 and 4.9 min,
respectively. The method was validated according to
International Conference on Harmonization (ICH) and
Food and Drug Administration (FDA) guidelines, and various
validation parameters were determined. Forced degradation
studies were also carried out in acid, base, oxidation,
and reduction media with a view to establishing the specificity and stability-indicating property. The practical
applicability of the method was confirmed by determining
CLR and AZL in combined dosage form. This reliable
and validated stability-indicating method for simultaneous
estimation of CLR and AZL is available for routine
analysis in the pharmaceutical industry as well as research
laboratories.
quantification of paracetamol and ibuprofen in their combined dosage form especially to get some more advantages over other methods already developed
for this combination. The method was validated according to United States Pharmacopeia (USP) guideline with respect to accuracy, precision, specificity,
linearity, solution stability, robustness, sensitivity, and system suitability. Forced degradation study was validated according to International Conference on
Harmonisation (ICH). For this, an isocratic condition of mobile phase comprising phosphate buffer (pH 6.8) and acetonitrile in a ratio of 65:35, v/v at a flow
rate of 0.7 mL/minute over RP C18 (octadecylsilane (ODS), 150 × 4.6 mm, 5 μm, Phenomenex Inc.) column at ambient temperature was maintained. The
method showed excellent linear response with correlation coefficient (R2) values of 0.999 and 1.0 for paracetamol and ibuprofen respectively, which were
within the limit of correlation coefficient (R2 0.995). The percent recoveries for two drugs were found within the acceptance limit of (97.0–103.0%). Intraand
inter-day precision studies of the new method were less than the maximum allowable limit percentage of relative standard deviation (%RSD) 2.0.
Forced degradation of the drug product was carried out as per the ICH guidelines with a view to establishing the stability-indicating property of this method
and providing useful information about the degradation pathways, degradation products, and how the quality of a drug substance and drug product changes
with time under the influence of various stressing conditions. The degradation of ibuprofen was within the limit (5–20%, according to the guideline of ICH),
while paracetamol showed 20% degradation in oxidation and basic condition.