Development of an Convenient and Robust Analytical
Technique for HPLC-based Determination of Silodosin in Capsule Formulation
Md. Abid Hasan1,3*, Naima Helal1,2,
Sajia Azmi3, Nursad Jahan Sultana3,
Sumaya Sarmina Nasir3, Rehnuma Jafreen4, Md Shadman Khan3,
Zobayda Islam Juthi2,
Kazi Jannatun Nayeem3
1Department of Pharmacy, University of Asia
Pacific, Dhaka, 1205, Bangladesh.
2Department of Pharmacy, World University of
Bangladesh, Dhaka, 1230, Bangladesh.
3Department of Pharmacy, University of Science and
Technology, Chittagong, Chattogram, 4202, Bangladesh.
4Department of Pharmacy, Jahangirnagar University,
1342, Bangladesh.
*Corresponding Author E-mail:
mdabid780@gmail.com
ABSTRACT:
Benign prostatic hyperplasia is commonly treated with
silodosin, a selective 1-adrenoreceptor antagonist. The goal is to create a
straightforward and accurate high performance liquid chromatographic technique
for silodosin detection and validate it in accordance with ICH standards.
Agilent HPLC 1260 Infinity series was used and empower software was utilized
for data processing. On a Cyano;
4.6mm × 25cm; 5mm, packing USP Octadecyl Silane column, silodosin was successfully separated by using
mobile phase, made up of a mixer of 4.0 pH ammonium acetate buffer: Acetonitrile:
Methanol (30:30:40) at 1.0ml/min flow rate and at a wavelength of 270 nm.The
silodosin responded at 3.9minutes. The validation parameters including
specificity, LOD/LOQ, linearity, accuracy, precision, robustness, and solution
stability, were verified for performance of the method. All the peaks were well
separated and there was no interference. Correlation coefficient of silodosin
was 1.00, which indicated the method maintain linearity at different
concentration. In precision study, the cumulative %RSD of silodosin was 0.88.
The percent recovery of the silodosin at different concentration was within the
(98.0-102.0) %. When the column temperature was increased/decreased by 3°C from
the real and the flow rate was increased/decreased by 0.2mL/min from the actual
rate, the system suitability resolution was still within the acceptable range.
The standard and sample solution were stable after 24 hours at both room
temperature and 5°C temperature. For the analysis of silodosin
in pharmaceutical goods, the confirmed HPLC method may be a workable analytical
approach.
KEYWORDS: Silodosin, HPLC, Benign prostatic hyperplasia,
Chromatography, Validation.
INTRODUCTION:
Beyond the age of 40, Benign Prostatic Hyperplasia
(BPH) affects many males. By the age of 60, BPH affects around 50% of men; by
the age of 85, it affects 90% of men1-3. 50% of BPH patients report
having symptoms of the urinary tract (lower) infection2.
One of the BPH therapies for mild Lower Urinary Tract
Syndrome (LUTS) is watchful waiting, whereas moderate to severe LUTS is treated
with pharmacologic therapy (such as 5-reductase inhibitors or 1-adrenergic
receptor antagonists), and severe LUTS is treated with surgery1.
Alpha-blockers are still the treatment for LUTS in
BPH. The FDA has authorized the new 1-Alpha-blocker silodosin since October
2008 at the recommended dose of 8 mg once daily. Clinical studies have shown
that this selective 1-Alpha-blocker is much more desirable and effectivefor
LUTS in BPH. Silodosin exhibits exceptional early efficacy and is as least as
effective as other 1-blockers4. It has been demonstrated that
silodosin inhibits the contraction of the prostate smooth muscle and has a
better selectivity for the dominant subtype of the Alpha-1-Adrenergic receptor
in prostate tissues. As a result, it is frequently utilized in therapeutic
settings to treat BHP5-7.
The goal of the research was to create a HPLC method
that would be cost effective, short process, and appropriate for daily
laboratory analysis of silodosin found in capsule formulation.Both qualitative
and quantitative testing of dosage forms is required for pharmaceutical
products quality. To ensure the stability and safety of the formulation
products, quantitative testing must be carried out during the course of its
lifecycle.
According to a literature study, many methods have
been employed to determine silodosin. Some of the methods were described in
HPLC8-15, Ultra Performance Liquid Chromatography (UPLC)16,
UV-Vis spectrophotometry17-19, spectrofluorimetric20, and
electrochemical methods21,22.
The most convenient instrumental analytical method for
determination of active pharmaceutical ingredients in pharmaceutical products
is RP-HPLC method23-35.
An effective, stability focused HPLC method was
developed, but the method was notreported all validation parameters, described
in ICH guidelines8. Two Liquid Chromatography-Mass Spectroscopy
(LC-MS) methods were developed and validated successfully for silodosin
detection in human plasma, not in capsule formulation9,12. By using
reverse phase HPLC techniques with DAD and UV detectors, silodosin was
separated successfully and the methods was validated successfully within the
short retention time, but these methods were applied in silodosin with others
active ingredients13-15. Another recently published study validated
Quality by Design (QbD) based method for silodosin in tablet dosage form, but
method was used florescence detector, which is not available in all laboratory11.
According to the literature study, there isn't a
single analytical easy, precise, and robust technique forevaluating silodosin
in capsuleformulation both qualitatively and quantitatively.
The intention of this work was to build a simple,
repeatable, linear, robust, and accurate single analytical approach for the
simultaneous measurement of silodosin in capsule formulation. According to a
thorough examination of the literature, for the rapid and simple detection of
silodosin in capsule formulations, the current method is the first robust
method ever created.
MATERIALS AND METHOD:
Instrument:
Agilent HPLC 1260 Infinity series for the
entire study was used along with DAD detector. The software, empower was used
for the processing of Chromatogram. Chromatographic Column for separation the
peak was used Zorbaz brand. Ultrasonic Bath was Power sonic 620, Hwashin, Korea
brand. Analytical balance for weighed the chemicals and reagents was Mettler
Toledo, Switzerland brand. pH meter was Mettler Toledo,
Switzerland brand. All the Instruments were calibrated with appropriate
instruction before use.
Chemical and Reagent:
Reagents were used from different reliable
resources. Silodosin was purchased from Lewens Lans pvt. Ltd. Gujarat, India.
Finished product, Silodosin capsule was purchased from local pharmacy.
Analytical grade Reagents, Acetonitrile from RCI labs can ltd, Thailand and
Methanol from Supelco Inc. Ammonium Acetate from Samchun, was used throughout
the study. Milli-Q was used to obtain purified water. Mannitol (DC grade),
Pregelatinised starch (starch 1500), Sodium Lauryl Sulfate, and Magnesium
Stearate were used as excipients in capsule formulation.
Solution Preparation:
Mobile Phase preparation: Taken 300mL of Bufferand 300mL
of Acetonitrile into 1L of beaker. Added 400mL of Methanol, sonicated for 5minutes,
after that filtered the solution through 0.22µ membrane filter and degassed 10minutes prior to
use. Mobile Phase was used as diluent.
Preparation of Buffer: Weighed1.156g of Ammonium Acetate into 1L of beaker containing 1L of water
and sonicated for 5 minutes then filtered through 0.22µm membrane filter and
degassed 10minutes before use.
Standard solution: 0.025mg/mL silodosin solution was prepared by transferring 25.0mg of silodosin working standard into a 100mL
volumetric flask. Pipetted out 5 mL of this solution in 50mL another volumetric
flask. Filtered the
preparation using 0.22µm PVDF syringe filter before injection.
Sample solution: 0.025mg/mL silodosin sample solution was prepared by transferring 781.25 mg crushed powder of capsule (equivalent to 25mg
of Silodosin) to a 100 mL volumetric flask. Accurately pipetted out 5mL of
solution in 50mL of volumetric flask. Filtered the preparation using 0.22µm PVDF syringe filter before
injection.
Chromatographic Condition:
The separation was done with Cyano; 4.6mm × 25cm; 5 mm,
packing USP Octadecyl Silane
columnand peak was detected at
270nm wavelength. The flow rate was 1.0 mL/min, Injection volume was 20µl, and
column oven temperature was 40°C.
Analytical Method Validation:
The method was validated according to ICH
guideline ICH-Q2 (R1)36 and United States of Pharmacopeia (USP)
general chapter 122537 with respect to system suitability,
specificity, LOD/LOQ, linearity, precision, accuracy, robustness and solution
stability.
System suitability study:
To check the system for suitability, the
Relative Standard Deviation (RSD) from five injections of standard solution,
tailing factor and USP theoretical plate count were checked. The %RSD of
Silodosin must be within the 2.0, Tailing factors not more than 2.0, and USP
theoretical plate must be not less than 2000.
Specificity:
To check the interference of diluent and
placebo with silodosin, specificity study was done. The separate 0.025 mg/mL
silodosin standard/sample solution andplacebo (mixture of excipients)were
prepared and injected individually. The chromatogram produced from the diluent
shouldn't have any interfering peaks at the retention time that corresponds to
the peak for silodosin. The retention time of peak due to silodosin in sample
solution shall be similar (±2%) to that of standard. Peak purity should pass
i.e.; Purity angle should be less than purity threshold.
LOD/LOQ:
Limit of Detection (LOD) and Limit of
Quantification (LOQ) were determined by using the signal to noise (S/N) ratio
method. Prepared silodosin standard solution at different low-level of
concentration as much as possible and injected. Determined the LOD and LOQ using equation: LOD = 3.3
σ/ s and LOQ = 10
σ/ s. [Where, σ =
the standard deviation of the response and S = the slope of the calibration
curve (estimated from the linearity curve)].
After determination
of LOD and LOQ Concentration, LOD and LOQ solution were prepared and injected.
In case of LOQ, S/N ratio of silodosin peaks must be greater than or equal to
10. The peak at LOD level should be detectable and S/N ratio must be more than
3.
Linearity:
Linearity of silodosin was demonstrated by
injecting silodosin standard solutionin concentration from LOQ concentration
level to 200% of 100% concentration of test solution (0.025mg/mL). The
correlation coefficient (R2) was calculated by using calibration
curve. The R2 must
not be less than 0.90.
Preparation of linearity stock solution: Transferred
25.00 mg of the Silodosin standard into a 100mL volumetric flask. Then, added
70mL of diluent, sonicate to dissolve it, and bring the volume up to the
desired level with the diluent. Finally, mixed well. The concentration of
silodosin was 0.25mg/mL. Table 1 represents the concentration of linearity
solution.
Table 1. Preparation of linearity solutions (LOQ to
200%)
|
Conc. (%)
|
Volume taken
from Linearity stock solution (mL)
|
Total volume
with diluent (mL)
|
Concentration
(mg/mL)
|
|
Silodosin
|
|
5%
|
1
|
250
|
0.001
|
|
10%
|
2
|
200
|
0.003
|
|
30%
|
3
|
100
|
0.008
|
|
50 %
|
5
|
100
|
0.013
|
|
80%
|
4
|
50
|
0.020
|
|
100 %
|
5
|
50
|
0.025
|
|
120 %
|
6
|
50
|
0.030
|
|
150 %
|
15
|
100
|
0.038
|
|
200 %
|
10
|
50
|
0.051
|
Precision:
Method Precision Study: Assess the repeatability by
performing six replicate measurements (n=6) of the assay of Silodosin 4 mg
Capsule as per test method at 100% of test concentration (0.025mg/mL) and
calculating the %RSD of the assay of Silodosin. The assay of Silodosin must be
within 98.0% - 102.0% of label claim and %RSD of assay of Silodosin must not be more than 2.0.
Intermediate Precision Study:
The intermediate
precision was done by another analyst with different HPLC at different day. Cumulative %RSD of each injection from 12
result of injections (method precision and intermediate precision) should be
not more than 10.0%.
Accuracy:
To
established the accuracy of the analytical method, prepared spiked sample
solution by spiking silodosin API and Placebo (Mixture of excipients) at LOQ,
50%, 100% and 150% of test concentration (0.025mg/mL). The recovery (%) should
be not less than 98.0% and should be not more than 102.0%.
Robustness:
Prepared the
standard solution at test concentration (0.025mg/mL). Inject the prepared
solution using different chromatographic conditions as shown below:
1.
By changing the Column
Temperature by +3°C from the actual column temperature (40°C).
2.
By changing the flow
rate by ± 0.2 mL/min from the actual flow rate (1.0
mL/min).
3. By changing the Mobile phase composition,
buffer and organic ratio by ±2%from
the actual ratio.
The %RSD for replicate injection must not be more than
2.0, theoretical plates more than 2000, and tailing must be with in 2.0.
Solution Stability:
To conducted solution stability, the
standard solution, sample solution and spiked sample solution were kept in room
temperature and refrigerator (5
) for 24 hours. After 24 hours, all
solution injected and compared with the initial results.
RESULTS AND DISCUSSION:
System Suitability:
The column
efficiency determined from Silodosin
peak was found 9224 theoretical
plates, tailing factor of the Silodosinpeakwas found 0.05, and the %RSD of five standard solution was
found 1.13%, indicate that the system is suitable for analysis.
Specificity study:
It was observed that after
all specific injection, silodosin
gave same response in sample (RT-3.992 minutes) and standard (RT-3.992
minutes) with respect to retention time (RT) and no interference due to diluent and placebo. The peak purity angle more than the purity
threshold in all the single injection.Therefore, the peak
response of method is considered as specific. Specificity study data are
presented in Table 2.
Table 2. Specificity Study
with peak purity angle and threshold
|
Name of the Solution
|
Name of Peak
|
Retention time (min)
|
Diluent
interference
|
Purity Angle
|
Purity Threshold
|
|
Diluent
|
-
|
-
|
Nil
|
-
|
-
|
|
Placebo
|
-
|
-
|
-
|
-
|
-
|
|
Standard Solution
|
Silodosin
|
3.992
|
-
|
3.86
|
4.25
|
|
Sample Solution
|
Silodosin
|
3.992
|
-
|
3.24
|
5.11
|
HPLC Chromatogram of
standard, sample, diluent, and placebo are given in the Figure 1-4.
Figure 1. Chromatogram of Standard
Figure 2. Chromatogram of Sample
Figure 3. Chromatogram of Diluent
Figure 4. Chromatogram of Placebo
LOD/LOQ:
The value of LOD was found 0.00036 mg/mL. The LOQ
value was found 0.00109 mg/mL.S/N
ratio of silodosin peaks was within the acceptance limit. The S/N ratio were
found greater than 3 in case of LOD, and greater than 10 in case of LOQ. The
peak at LOD level was detectable in all six replicates.
Linearity:
The correlation coefficient of silodosin was found
1.00.
Figure 3: Linearity graph for Silodosin (Concentration vs. Area)
The results were well within acceptance limit. Thus, the method is considered as linear. Linearity data are presented in Figure 3.
Precision:
Method Precision/Repeatability Study: % RSD of
silodosin was 0.52% in six sample solutions. Assay result in sample solution was found
98.92% of the level claim of silodosin, the method meets the requirement of
method precision.
Intermediate
Precision/Repeatability Study:
%RSD
of silodosin was 0.14% in six sample solutions. Assay result in sample solution was found 98.24% of
the level claim of silodosin, the method meets the requirement of
intermediate precision.
Cumulative % RSD of
silodosin was 0.88% in 12 injections (method precision and intermediate
precision). Hence, the method
meets the requirement of Precision study/Ruggedness.
Accuracy:
The accuracy in terms of
percent recovery of four different concentration (s) were well enough within
the acceptance limit (98.00-102.00) %. The %RSD was below 2.0. Hence, the
method meets the requirement of accuracy. The Accuracy study data are presented in Table 3.
Table 3. Silodosin Recovered in accuracy study
|
Sample Name
|
Amount of silodosin API taken (mg)
|
Area of Silodosin
|
Amount recovered (mg)
|
% Recovery
|
|
Accuracy LOQ -1
|
1.01
|
20643
|
0.99
|
98.46
|
|
Accuracy LOQ -2
|
1.04
|
21323
|
1.03
|
98.77
|
|
Accuracy LOQ -3
|
1.03
|
21324
|
1.30
|
99.73
|
|
Accuracy 80% -1
|
20.11
|
417248
|
20.10
|
99.95
|
|
Accuracy 80% -2
|
20.13
|
414962
|
19.99
|
99.31
|
|
Accuracy 80% -3
|
20.05
|
411537
|
19.83
|
98.88
|
|
Accuracy 100% -1
|
25.20
|
516264
|
24.87
|
98.69
|
|
Accuracy 100% -2
|
25.23
|
521925
|
25.14
|
99.66
|
|
Accuracy 100% -3
|
25.21
|
521035
|
25.10
|
99.57
|
|
Accuracy 120% -1
|
30.08
|
617353
|
29.74
|
98.87
|
|
Accuracy 120% -2
|
30.04
|
616947
|
29.72
|
98.94
|
|
Accuracy 120% -3
|
30.11
|
612812
|
29.52
|
98.05
|
|
|
|
Minimum
|
|
98.05
|
|
|
|
Maximum
|
|
99.95
|
|
|
|
Average
|
|
99.1
|
|
|
|
%RSD
|
|
0.59
|
Robustness Study:
The robustness study was
satisfactory with column oven temperature, flow rate, and mobile phase
composition variation. The %RSD of silodosin standard was found are given in
Table 4.
Table 4. %RSD at different condition from actual
condition in robustness study
|
Condition
|
%RSD
|
|
Column oven temperature at 37°C
|
0.43
|
|
Column oven temperature at 43°C
|
0.56
|
|
Flow rate at 0.8 mL/min
|
0.85
|
|
Flow rate at 1.2 mL/min
|
0.77
|
|
Mobile Phase ratio, Buffer: Acetonitrile:
Methanol (29.40: 30.30:40.30)
|
0.55
|
|
Mobile Phase ratio, Buffer: Acetonitrile:
Methanol (30.60:29.70:39.70)
|
0.53
|
Solution Stability Study:
The solution of standard,
sample, and spiked sample was stable up to 24 hours as they provided same
response as initially provided even if in the room temperature and refrigerator
(5°C). The
differences from initial to 24 hours result are presented in Table 5.
Table 5. % Difference of initial fresh solution and
solution after 24 hours
|
Sample Name
|
% Difference
at room temperature
|
% Difference
at 5°C temperature
|
|
Standard Solution
|
0.6
|
0.5
|
|
Sample Solution
|
0.4
|
0.5
|
|
Spiked Sample
Solution
|
0.5
|
0.4
|
CONCLUSION:
This work was aimed to developed short run
time, simple, easy to conduct, and cost-effective analytical HPLC method for
determination of silodosin in capsule dosage form. In pharmaceutical
manufacturing site, finished products required quantification before marketed.
The literature review concluded that there are no easy, robust validated
analytical methods for silodosin detection with less cost. Based on the
findings, the placebo interference, linearity, accuracy, precision, robustness,
and solution stabilitymet the criteria. The logical
conclusion is that silodosin can be detected using this analytical approach and
this method is convenient enough for daily analysis.
ACKNOWLEDGMENTS:
We are thankful to the respectful teacher of Department
of Pharmacy, World University of Bangladesh for providing facilities to conduct
this work. All co-authors are contributed equally in writing the manuscripts
and compared with published data.
CONFLICTS OF INTEREST:
The authors declare that there are no conflicts of
interest regarding the publication of this article.
FUNDING:
This work was conducted by self-fund.
REFERENCES:
1.
Committee AUA P G. AUA
guideline on management of benign prostatic hyperplasia (2003) Chapter 1:
Diagnosis and treatment recommendations. The Journal of Urology. 2003; Aug;
170(2 pt 1): 530-547. doi.org/10.1097/01.ju.0000078083.38675.79
2.
Wasserman N F. Benign
prostatic hyperplasia: A review and ultrasound classification. Radiologic Clinics
of North America. 2006; Sep; 44(5): 689-710.doi.org/10.1016/j.rcl.2006.07.005.
3.
Thorpe A, Neal P D.
Benign prostatic hyperplasia. The Lancet. 2003; 362(9366): 1359-1367.
doi.org/10.1016/S0140-6736(03)13073-5
4.
Rossi M, Roumeguere T.
Silodosin if the treatment of benign prostatic hyperplasia. Drug design,
development and therapy. 2010; 4: 291-297. doi.org/10.2147/DDDT.S10428
5.
Marks L S, Gittelman M
C, Hill L A, Volinn W, Hoel G. Silodosin in the Treatment of the Signs and
Symptoms of Benign Prostatic Hyperplasia: A 9-Month, Open-label Extension
Study. Urology. 2009; 74: 1318–1322. doi: 10.1016/j.urology.2009.06.072
6.
Roehrborn C G, Cruz F,
Fusco F. α1-Blockers in Men with Lower Urinary Tract Symptoms Suggestive
of Benign Prostatic Obstruction: Is Silodosin Different? Advances in Therapy.
2017; 33: 2110–2121. doi:10.1007/s12325-016-0423-5
7.
Yoshida M, Kudoh J,
Homma Y, Kawabe K. Safety and efficacy of silodosin for the treatment of benign
prostatic hyperplasia. Clinical Interventions in Aging. 2011; 6: 161–172. doi:
10.2147/cia.s13803
8.
Er E, Erk N. An
effective and sensitive stability-indicating chromatographic approach based on
HPLC for silodosin assay. Journal of Analytical Science and Technology. 2016;
7:20. doi.org/10.1186/s40543-016-0100-y
9.
Zhao X, Liu Y, Xu J,
Zhang D, Zhou Y, Gu J, Cui Y. Determination of silodosin in human plasma by
liquid chromatography-tandem mass spectrometry. Journal of Chromatography B.
2009; 877(29): 3724–3728. doi.org/10.1016/j.jchromb.2009.08.025
10.
Harischandran S, Shankar
L R, Raju R, Shibi A, Sayana P S. Method development and validation RP-HPLC
method for assay of silodosin in pharmaceutical dosage form. International
Journal of Pharmaceutical Sciences and Research. 2012; 1(4): 141–145.
11.
Yaman M E, Akman T C.
Optimization of HPLC-FLD Conditions Using Analytical Quality by Design Approach
for Quantification of Silodosin in Pharmaceutical Dosage Form. Erzincan
University Journal of Science and Technology. 2021; 14 (3): 993-1005.
doi.org/10.18185/erzifbed.955967
12.
Yadlapalli S S R, Katari
N K, Manabolu S B, Ravi V B. Simultaneous estimation of silodosin and silodosin
β-Dglucuronide in human plasma using LC-MS/MS for a pharmacokinetic study.
Journal of Taibah University for Science. 2018; 12 (4): 393-400.
doi.org/10.1080/16583655.2018.1490562
13.
Nataraj KS, Srinivasa R
A, Harshitha S, Pravallika K. Analytical Method Development and Validation for
the Estimation of Silodosin and Dutasteride in Capsule Dosage Form by RP-HPLC
Method. Journal of Drug Metabolism & Toxicology. 2020; 11(2): 245. 10.35248/2157-7609.20.11.245
14.
Shah H P, Khandar A,
Deshpande S, Bagade S. Novel RP-HPLC method for simultaneous estimation of
silodosin and dutasteride in multiunit solid dosage form. Research Journal of
Pharmaceutical, Biological and Chemical Sciences. 2014; 5(2): 801-810.
15.
Gupta A, Mishra S K. A
Novel Analytical Method for Simultaneous Quantification of Silodosin and
Tadalafil by RP-HPLC. Journal of Pharmaceutical Research International. 2021;
33(39B): 193-202. doi.org/10.9734/jpri/2021/v33i39B32195
16.
Shaik J V, Saladi S,
Sait S S. Development of Stability-Indicating UHPLC Method for the Quantitative
Determination of Silodosin and Its Related Substances. Journal of
Chromatographic Science. 2014; 52(7): 646–653. doi.org/10.1093/chromsci/bmt094
17.
Ahmed S, Abdelkawy M,
Mohamed T A, Nasser N. Validated stability-indicating spectrophotometric
methods for the determination of Silodosin in the presence of its degradation
products.Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy.
2018; 202: 131–145. doi.org/10.1016/j.saa.2018.04.046
18.
Mounika C H, Umadevi N,
Sudheerbabu I. New visible spectrophotometric for the estimation of silodosin
in pharmaceutical formulations. International Journal of Research in Pharmacy
and Chemistry. 2013; 3(3): 595–597.
19.
Aneesh T P, Aiyalu R.
Method development and validation for the estimation of silodosin in bulk and
pharmaceutical dosage forms using UV-VIS spectrophotometry. Asian Journal of
Pharmaceutical and Clinical Research. 2012; 5(4): 4–6.
20.
Bhamre P, Rajput S J.
Spectrofluorimetric method for the determination of silodosin in bulk and
pharmaceutical dosage form. Indo American Journal of Pharmaceutical Research.
2014; 4(10): 5106–5110.
21.
Toker B, Er E, Erk N.
Development of voltammetric techniques for the determination of silodosin in
pharmaceutical formulation at glassy carbon electrode. Revue Roumaine de
Chimie. 2014; 59(5): 311–316.
22.
Er E, Celikkan H, Erk,
N. An ultra-sensitive 2D electrochemical sensor based on a
PtNPs@graphene/Nafion nanocomposite for determination of α1-AR antagonist
silodosin in human plasma. Analytical Methods. 2017; 9: 3782–3789.
23.
Mahmoud M. Sebaiy,
Abdullah A. El-Shanawany, Sobhy M. El-Adl, Lobna M. Abdel-Aziz, Hisham A.
Hashem. Rapid RP-HPLC Method for Simultaneous Estimation of Norfloxacin and
Tinidazole in Tablet Dosage Form. Asian J. Pharm. Ana. 2011; 1(4): Oct. - Dec.
79-84.
24.
L. Satyanarayana, S.V.
Naidu, M. Narasimha Rao, Reddy Suma Latha. The Estimation of Nilotinib in
Capsule dosage form by RP-HPLC. Asian J. Pharm. Ana. 2011; 1(4): 100-102.
25.
Sharmin Reza Chowdhury,
Mahfuza Maleque, Mahbubul Hoque Shihan. Development and Validation of a Simple
RP-HPLC Method for Determination of Caffeine in Pharmaceutical Dosage Forms.
Asian J. Pharm. Ana. 2012; 2(1): 1-4.
26.
P. Janaki Pathi, N.
Appala Raju. The Estimation of Epalrestat in Tablet Dosage Form by RP-HPLC.
Asian J. Pharm. Ana. 2012; 2(2): 49-51.
27.
Y Rajendraprasad, KK
Rajasekhar, V Shankarananth, S Bharath kumar, G Dileep kumar, T Sreelekha.
RP-HPLC Method for the Estimation of Domperidone in Bulk and Pharmaceutical
Formulations. Asian J. Research Chem. 2009; 2(4): 561-564.
28.
K Ananda kumar, G
Kumaraswamy, T Ayyappan, ASK Sankar, D Nagavalli. Validated RP-HPLC Method for
the Estimation of Eszopiclone in Bulk and Tablet Dosage Form. Asian J. Research
Chem. 2010; 3(1): 63-66.
29.
Antakli S, Alahmad A,
Badingki H. Simultaneous Determination of Sodium Benzoate and Potassium Sorbate
Preservatives in Foodstuffs Using High-Performance Liquid Chromatography. Asian
J. Research Chem. 2010; 3(1): 178-182.
30.
Amrish Sharma, Mukul
Tailang, Bhaskar Gupta, Ashish Acharya. RP HPLC Determination of Amlodipine in
Its Pharmaceutical Dosage Forms. Asian J. Research Chem. 2010; 3(1): 129-131.
31.
Prabhu S, Vijay
Amirtharaj R, Senthilkumar N. Simultaneous RP-HPLC Method Development and
Validation of Cefixime and Ofloxacin in Tablet Dosage Form. Asian J. Research
Chem. 2010; 3(2): 367-369.
32.
T.M. Kalyankar, R.B.
Kakde. Reversed-Phase Liquid Chromatographic Method for Simultaneous
Determination of Metformin and Repaglinide in Pharmaceutical Preparations.
Research J. Pharma. Dosage Forms and Tech. 2011; 3(5): 233-237.
33.
Shalini Pant, Krishan
Pal. Development and Validation of a Simultaneous HPLC Method for Assay and
Dissolution of Bisoprolol fumarate and Amlodipine besylate in Pharmaceutical
Dosage. Research J. Pharma. Dosage Forms and Tech. 2012; 4(1): 62-66,
34.
N Appala Raju, Shabana
Begum. Simultaneous RP-HPLC Method for the Estimation of the Emtricitabine,
Tenofovir Disoproxil Fumerate and Efavirenz in Tablet Dosage Forms. Research J.
Pharm. and Tech. 2008; 1(4): 522-525.
35.
Akash Shelke, Someshwar
Mankar, Mahesh Kolhe. Development and Validation of RP-HPLC Method for
estimation of Secnidazole in API and Pharmaceutical Dosage Form. Research
Journal of Science and Technology. 2021; 13(2): 100-4.
36.
International Conference
on Harmonization (ICH) of Technical Requirements for Registration of
Pharmaceuticals for Human Use, Topic Q2 (R1). Validation of Analytical
Procedures: Text and Methodology. International Conference on Harmonization
(ICH), Geneva, Switzerland. 2005 November.
37.
U.S. Pharmacopeial
Convention. The U.S. Pharmacopoeia (USP 43), National Formulary (NF 38) General
Chapters: 1225. Validation of Compendial Procedures. Rockville. 2020.