4.A.1 Discussion. Assay method development and Validation of Ziprasidone Hydrochloride

Transcription

1 4.A.1 Discussion. Assay method development and Validation of Ziprasidone Hydrochloride 4.A.1.1. HPLC method development and optimization In the present study the main target for the development of chromatographic method was to get the reliable method for the quantification of Ziprasidone hydrochloride from bulk drug and can be applied for the degradable products,as very few researcher as carried and reported systematic study of HPLC and UV methods for estimation of Ziprasidone Hydrochloride Monohydrate which were sophisticated, but time consuming. Thus,the present study was aimed for development of speedy and cost effective HPLC technique for determination of Ziprasidone Hydrochloride Monohydrate as bulk and in dosage forms. The chromatographic method was optimized by changing various parameters, such as the mobile phase composition, ph of the buffer used in the mobile phase. Retention time and separation of peak of Ziprasidone Hydrochloride Monohydrate were dependent on ph of the buffer and the percentage of methanol. Various blends of solvent systems in varying proportions were tried as mobile phase by G.Srinubabu, 1-3 Different mobile phases were tried, but satisfactory separation and good symmetrical peak were obtained with mobile phases having triethylamine buffer P H = 3.0 with orthophosphuric acid.530 ml of buffer mixed with 150 ml acetonitrile and 320 ml of methanol,the volume was 53:15:32,v/v/v,it was filtered and degased. and Column used YMC pack C18, 250 x 4.6 mm, 5µm found to comparatively better and gave the graph with better gaussian shape at retention time 9.80 min. 4.A.1.2. Method validation Validation of an analytical method is the process by which it is established by laboratory studies, that the performance characteristics of the method meet the requirements for the intended analytical application. 4 Validation is required for any new or amended method to ensure that it is capable of giving reproducible and reliable results, when used by different operators employing the same equipment in the same or different laboratories. The type of validation programme required depends entirely on the particular method and its proposed applications. The proposed analytical method was validated for the parameters such as linearity, precision, accuracy, specificity, limit of quantification [LOQ], limit of detection [LOD],Forced degradation and robustness

2 4.A.1.3. System precision: Precision is the measure of the degree of repeatability of an analytical method under normal operation and is normally expressed as the percent relative standard deviation for a statistically significant number of samples. The two most common precision measures are 'repeatability' and 'reproducibility'.these are expression of two extreme measure of precision which can be obtained. In the present finding Standard solution of Ziprasidone Hydrochloride Monohydrate were prepared as per testing procedure and injected into the HPLC system in six replicates. The values of % relative standard deviation (NMT 2.0%) for peak area obtained in six replicate injections were reported in Table-3.A.1.1. thus showing that the equipment used for the study worked correctly for the developed analytical method, and being highly repetitive 8. Figure -4.A.1. A chromatogram of the Ziprasidone Hydrochloride standard 296

3 4.A.1.4. Linearity A linear study identifies a specified concentration range where analytes response is linearly proportional to the concentration. The present study reveals that standard curve found to be linear over the concentration range of ppm. The results are depicted in Table 3.A.1.2 of chapter -3. The equation of the standard curve relating the peak area to the Ziprasidone concentration in this range was y = 480x The drug showed good linearity in the range of ppm with coefficient of correlation value for peak area (Table-3.A.1.2) Figure-4. A.2. Linearity graph of Ziprasidone HCl y = 480x R² =

4 4.A.1.5.Accuracy Accuracy is popularly used to describe the measure of exactness of an analytical method, or the close of an agreement between the value, which is accepted as a conventional, true value or as an accepted reference value, and the value found.it is properly a qualitative concept and the correct term is 'bias'.the bias of a method is an expression of how close the mean of asset of results (produced by the method) is to the true value. Bias is usually determined by study of relevant reference materials or by spiking studies 9 Accuracy, sometimes also referred to as recovery is an indicator of the trueness of the test measurements. To determine the accuracy of the method three quality control samples were used. The samples chosen were such to represent the entire range of the standard curve i e lower, middle and higher concentration of the range. 10 In the present finding recovery studies were conducted after addition of standard drug solution at three different levels i.e. 50 %, 100 %, and 150 % to pre-analyzed sample solution and to check the accuracy of the method, Similar work as been also reported by Chudasama, The results of the finding are reported in chapter 3 and in Table-3.A A.1.6. Robustness The robustness of an analytical procedure refers to its capability to remain unaffected by small and deliberate variations in method parameters The percentage recovery of Ziprasidone Hydrochloride Monohydrate was good under most conditions and didn t show any significant change when the critical parameters were modified. The tailing factor for Ziprasidone Hydrochloride Monohydrate was always less than 2.0 and it was well separated under all the changes carried out. Considering the modifications in the system suitability parameters and the specificity of the method it can conclude that the method is robust. Similar result for other drugs were reported by Ahmed et.al 15 4.A.1.7. Forced degradation : Forced degradation studies are used to facilitate the development of analytical methodology, to gain a better understanding of active pharmaceutical ingredient (API) and drug product (DP) stability, and to provide information about degradation pathways and degradation products 16. In present finding Forced degradation studies of Ziprasidone Hydrochloride Monohydrate were carried under different stress condition such as acid, alkali, peroxide,thermal and water according to ICH guideline shown in table- 3.A % degradation observed in 1.0 N 298

5 HCl. The peaks of the degradation products were well resolved. 17 The degradation study showed that Ziprasidone Hydrochloride was stable to chemical oxidation study, dry heat and alkali hydrolysis where as it was highly susceptible to acid hydrolysis. Figure -4. A.3.A chromatogram of the degradation Ziprasidone Hydrochloride alkali 299

6 4.A.2. Assay method development and Validation of Duloxetine Hydrochloride. 4.A.2.1 HPLC method development and optimization In present investigation the main target was for the development of chromatographic method to get the reliable method for the quantification of Duloxetine hydrochloride from bulk drug and which is applicable for the degradable products, for that number of systematic trials were performed to optimize the chromatographic conditions for developing a sensitive, precise and accurate RP-HPLC method for the analysis of Duloxetine HCl in pharmaceutical dosage forms. Various blends of solvent systems in varying proportions were tried as mobile phase by O Neil and others The present method contains mobile phase 0.1% Orthophosphuric acid buffer as A and acetonitrile as mobile phase B, gradient program mention in expermential details and column used Kromasil C18, 250 x 4.6 mm, 5µm found to comparatively better and gave the graph with better gaussian shape at retention time min. 4.A.2.2 Method validation The validation of analytical procedures is based on the four most common types of analytical procedures:- Identification tests, Quantitative tests for impurities' content,limit tests for the control of impurities, Quantitative tests of the active moiety in samples of drug substance or drug product or other selected component(s) in the drug product 20 In the present study the developed method was validated, as described below, for various parameters like linearity and range, accuracy, precision, ruggedness, system suitability, specificity, LOQ,and LOD. 4.A.2.3 Precision The precision of an analytical procedure expresses the closeness of agreement (degree of scatter) between a series of measurements which is obtained from multiple sampling of the same homogeneous sample under the prescribed conditions. Precision may be considered at three levels: repeatability,intermediate precision and reproducibility. Precision should be investigated using homogeneous, authentic samples. However, if it is not possible to obtain a homogeneous sample, it may be investigated using artificially prepared samples or a sample solution. The precision of an analytical procedure is usually expressed as the variance, standard deviation or coefficient of variation of a series of measurements

7 In our study instrument precision was determined by performing repeatability test and the %RSD (NMT 2.0%) values for Doluxtine hydrochloride and are reported in Chapter 3, Table-3.A.2.2 Figure -3.A.4. A chromatogram of the Doluxetine Hydrochloride standard 4.A.2.4. LOD and LOQ The Quantitation limit of an individual analytical procedure is the lowest amount of analyte in a sample which can be quantitatively determined with suitable precision and accuracy. The Quantitation limit is a parameter of quantitative assays for low levels of compounds in sample matrices and is used particularly for the determination of impurities or degradation products. 21 The detection limit of an individual analytical procedure is the lowest amount of analyte in a sample which can be detected but not necessarily quantitated as an exact value. 21 LOD and LOQ of the drug were calculated using the following equations according to International Conference on Harmonization (ICH) guidelines. 22 LOD = 3.3 /S LOQ = 10 /S where = the standard deviation of the response and S = the slope of the regression equation and were found to be and µg/ml.(table-3.a.2.1). The present study reveals that the method is sensitive for the determination of Doluxtine hydrochloride. 4.A.2.5. Linearity and Range Linearity is the method's ability to obtain results which are either directly, or after mathematical transformation proportional to the concentration of the analyte within a given range. The range of the method is the interval between the upper and lower levels of an analyte that have been 301

8 determined with acceptable precision, accuracy and linearity. It is determined by calculating the regression line using a mathematical treatment of the results (ie least mean squares) vs analyte concentration.. 23 In present study linearity of the method was evaluated at five concentration levels by diluting the standard stock solution. The calibration curve for Doluxetine hydrochloride was prepared by plotting area v/s concentration. Calibration data for Doluxtine hydrochloride are given in Table Table-3.A.2.3. The linearity plot of Doluxetine hydrochloride was found to be linear and correlation coefficient for Doluxetine hydrochloride i.e y = x The present study reveals that linearity observed were in the expected concentration range, demonstrating suitability of the method for analysis, which may be attributed to the method linear in the specified range for the analysis of Doluxtine hydrochloride.our findings are in good aggrement with the earlier reported work on other drugs 24 Figure-4. A.5. Linearity graph of Duloxetine Hydrochloride y = 747.3x R² =

9 4.A.2.6. Accuracy The accuracy of an analytical procedure expresses the closeness of agreement between the value, which is accepted either as a conventional true value or an accepted reference value and the value found. This is sometimes termed trueness. Accuracy, sometimes also referred to as recovery is an indicator of the trueness of the test measurements. To determine the accuracy of the method three quality control samples were used. The samples chosen were such to represent the entire range of the standard curve i.e lower, middle and higher concentration of the range 10 The recovery experiments were carried out by the standard addition method. The recoveries obtained by the RPHPLC method for Doluxetine hydrochloride are depicted in Table 3.A.2.4. The method was found to be accurate with % recovery 99% % and found to be in acceptable %RSD of not more than 2% at each level. 4.A.2.7. Robustness The robustness of an analytical procedure is a measure of its capacity to remain unaffected by small, but deliberate variations in method parameters and provides an indication of its reliability during normal usage. 21. The present study reveals that the method found to be robust, which may be attributed to the small but deliberate changes in the method and low value of relative standard deviation. These parameters have no detrimental effect on the method performance. Similar results are also reported by different research during their study A.2.8. Forced degradation Stress testing of the active substance can help to identify the likely degradation products, which can in turn help to establish the degradation pathways and the intrinsic stability of the molecule and validate the stability indicating power of the analytical procedures used. The nature of the stress testing depends on the individual active substance and the type of Pharmaceutical product involved. 25 In our present investigation forced degradation study were carried out by subjecting the drug to acid and alkali hydrolysis, chemical oxidation, dry heat degradation and photolytic (sun light) conditions was carried.. The peaks of the degradation products were well resolved. The study reveals that chromatograms of alkali degraded sample showed % degradation in 0.2 N NaOH. The Doluxetine hydrochloride was found to be stable to rest of the conditions like oxidative stress degradation, dry heat degradation and acid hydrolysis. Our findings showed that 303

10 Doluxtine hydrochloride was stable to chemical oxidation study, dry heat and alkali hydrolysis while it was highly susceptible to alkali hydrolysis which is in good aggrement with the work published earlier. 26 Figure-4. A.6. A chromatogram of the Doluxetine Hydrochloride alkali degradation 304

11 4.A.3. Assay method development and Validation of carmustine 4.A.3.1. HPLC method development and optimization In our present work the main target was for the development of chromatographic method was to get the reliable method for the quantification of Carmustine from bulk drug and which will be also applicable for the degradable products. Few HPLC and UV methods have been reported for estimation of Carmustine which are sophisticated, but time consuming. The present study was aimed at development of speedy and cost effective HPLC technique for determination of Carmustine as bulk and in dosage forms. The chromatographic method was optimized by changing various parameters, such as the mobile phase composition, ph of the buffer used in the mobile phase. Retention time and separation of peak of Carmustine were dependent on ph of the buffer and the percentage of methanol. Various blends of solvent systems in varying proportions were tried as mobile phase by Nataranjan et al 27. The present study reveals that during use of different mobile phases 0.01 M Potassium dihydrogen phosphate at ph 3.2 with Orthophosphuric acid and acetonitrile in the ratio of (70:30,v/v) and column temperature 30 C showed better peak shap, finally mobile phase filtered and degased. The Column used YMC ODS-A C18, 250 x 4.6 mm, 5µm found to comparatively better and gave the graph with better gaussian shape at retention time min min. 4.A.3.2. Method validation The Method was validated based on the International Conference on Harmonization (ICH) Guidelines The method validation parameters checked were specificity, linearity, accuracy, precision, limit of detection, limits of quantitation and robustness. The analytical method was validated as per ICH guidelines with respect to parameters such as linearity, precision, accuracy, specificity,forced degradation and robustness. 4.A.3.3. System precision: The precision of an analytical method is the closeness of a series of individual measurements of an analyte when the analytical preocedure is applied repeatedly to multiple aliquots of a single homogeneous volume of biological matrix. The precision is calculated as coefficient of variation (C. V.), i.e., relative standard deviation (RSD). The measure RSD can be subdivided into three categories: repeatability (intra-day precision) and reproducibility (between laboratories precision)

12 In the present finding Standard solution of Carmustine were prepared as per testing procedure and injected into the HPLC system in six replicates.the study reveals that the values of % relative standard deviation 0.20 (NMT 2.0%) for peak area obtained in six replicate injections indicates that the equipment used for the study worked correctly for the developed analytical method, and being highly repetitive. It is in good agrrement with shinde et.al and others The results are reported in chapter 3, Table-3.A.3.1. Figure -4.A.7. A chromatogram of the carmustine standard 4.A.3.4. Linearity The linearity of an analytical procedure is its ability (within a given range) to obtain test results, which are directly proportional to the concentration (amount) of analyte in the sample The equation of the standard curve relating the peak area to the carmustine concentration were in the range of y = 751x In our findings the drug showed good linearity in the range of ppm with coefficient of correlation value for peak area (Table-3.A.3.2).. The standard curve found to be linear over the concentration range of ppm. 306

13 Figure-4. A.8. Linearity graph of Carmustine y = 751x R² = A.3.5. Accuracy Accuracy, sometimes also referred to as recovery is an indicator of the trueness of the test measurements. In our present study to determine the accuracy of the method by taking three samples were used. The samples chosen were such that they represent the entire range of the standard curve i.e lower, middle and higher concentration of the range. Recovery studies are carried after addition of standard drug solution at three different levels i.e. 50 %, 100 %, and 150 % to pre-analyzed sample solution to varify the accuracy of method similar study for different drugs was also carried by Susan et al and others The results are given in table-3.a.3.3, 3.A.3.4 and 3.A A.3.6. Robustness In the present findings the percentage recovery of Carmustine was good under most conditions and didn t show any significant change when the critical parameters were modified. The tailing factor for Carmustine was always less than 2.0 and it was well separated under all the changes carried out. The modifications made in the system suitability parameters and the specificity of the method shows that the method is robust. Robustness parameter flow plus,flow minus,ph plus and ph minus results are given in table-3.a.3.6, 3.A.3.7 and 3.A

14 4.A.3.7. Forced degradation : In present investigation the forced degradation of Carmustine under different stress condition such as acid, alkali, peroxide,thermal and water according to ICH guidline shown in table- 3.A % degradation observed in 0.1 N NaOH. The peaks of the degradation products were well resolved shown in fig-3a.17. The degradation study reveals that Carmustine was stable to chemical oxidation study, dry heat and acid hydrolysis while it was highly susceptible to alkali hydrolysis. Figure-4. A.9. A chromatogram of the carmustine alkali degradation. 308

15 4.A.4. Assay method development and Validation of Irinotecan Hydrochloride 4.A.4.1. HPLC method development and optimization In our present work the main target for the development of chromatographic method was to get the reliable method for the quantification of Irinotecan hydrochloride from bulk drug and which are also applicable for the degradable products. It was also observed that few HPLC and UV methods have been reported for estimation of Irinotecan hydrochloride which are sophisticated, but time consuming. The present study was aimed at development of speedy and cost effective HPLC technique for determination of Irinotecan hydrochloride as bulk and in dosage forms. The chromatographic method was optimized by changing various parameters, such as the mobile phase composition, ph of the buffer used in the mobile phase. Retention time and separation of peak of Irinotecan hydrochloride were dependent on ph of the buffer and the percentage of methanol. HPLC study carried out by using various blends of solvent systems in varying proportions were tried as mobile phase as reported earlier Different mobile phases were tried, but satisfactory separation and good symmetrical peak were obtained with the mobile 2.0gm Sodium dihydrogen phosphate and 1.0gm 1-Octane Sulphonic acid salt in 1000 ml 550 ml buffer,170 ml acetonitrile and 280 ml methanol mixed filtered and degased. The column temperature was maintained at 45 C have better peak shape. and Column used were Inertsil ODS 3V C18(250X4.6)mm,5µ found to comparatively better and gave the graph with better gaussian shape at retention time min. 4.A.4.2. Method validation Method validation of an analytical procedure is to demonstrate suitability for intended purpose. To meet current pharmaceutical regulatory guidelines i.e. USP, ICH and EP, a number of criteria such as specificity, linearity, precision, accuracy, sensitivity and robustness are determined investigated in order to validate analytical methods. 5 4.A.4.3. System precision: Precision which was an important aspect of method validation were carried and used to ensure adequate performance of the chromatographic system. Retention time (RT), number of theoretical plates (N) and tailing factor (T) Standard solution of Irinotecan hydrochloride was prepared as per testing procedure and injected into the HPLC system in six replicates. 171 The values of % relative standard deviation 0.14 (NMT 2.0%) for peak area obtained in six replicate injections are reported in Table-3.A.4.1. In our finding the the low value of relative standard 309

16 deviation attributes that the method is robust.similar results are also reported by different research during their study.thus showing that the equipment used for the study worked correctly for the developed analytical method, and being highly repetitive. 43 Figure -3.A.10. A chromatogram of the Irinotecan Hydrochloride standard prepration. 4.A.4.4. Linearity linearity is a highly successful parameter for method accuracy and defined as the method's ability to obtain results which are either directly, or after mathematical transformation proportional to the concentration of the analyte within a given range. It is determined by calculating the regression line using a mathematical treatment of the results (i.e least mean squares) vs analyte concentration.a linear study identifies a specified concentration range where analytes response is linearly proportional to the concentration. The standard curve found to be linear over the concentration range of ppm. The equation of the standard curve relating the peak area to the Irinotecan Hydrochloride concentration in this range was y = 813x The present study reveals that,the drug showed good linearity in the range of ppm with coefficient of correlation value for peak area (Table-3.A.4.2). 310

17 Figure- 4. A.11. Linearity graph of Irnotecan Hydrochloride y = 813x R² = A.4.5. Accuracy Accuracy methods have been described as a measure of the closeness of test results obtained by a method to the true value. Accuracy indicates the deviation between the mean value found and the true value. lt is determined by applying the method to samples to which known amounts of analyte have been added. It is analysed against standard and blank solutions to ensure that no interference exists. The accuracy is then calculated from the test results as a percentage of the analyte recovered by the assay. Accuracy,it is sometimes also referred to as recovery is an indicator of the trueness of the test measurements. In our present investigation to determine the accuracy of the method three quality control samples were used. The samples chosen were such to represent the entire range of the standard curve i.e. lower, middle and higher concentration of the range To check the accuracy of the method, recovery studies were conducted after addition of standard drug solution at three different levels i.e. 50 %, 100 %, and 150 % to pre-analyzed sample solution. Our findigs good aggrement with the earlier reported work on other drugs by Herben et al The results of the findings are given in table-3.a A.4.4 and 3.A

18 4.A.4.6. Robustness Robustness is the ability of a method to tolerate variations of parameters without significant change in the result 47.In the present findings recovery of Irinotecan hydrochloride was good under most conditions and didn t show any significant change when the critical parameters were modified. The tailing factor for Irinotecan hydrochloride was always less than 2.0 and it was well separated under all the changes carried out Considering the modifications in the system suitability parameters and the specificity of the method it can conclude that the method is robust. Robustness parameter flow plus,flow minus, Temperature plus and Temperature minus results are depicted in table-3.a.4.6, 3.A.4.7 and 3.A A.4.7. Forced degradation : In present investigation the forced degradation of Irinotecan hydrochloride under different stress condition such as acid, alkali, peroxide,thermal and water according to ICH guidline reported in table- 3.A The present study reveals that 15.88% degradation observed in 0.2 N NaOH. Which is an indicative of development of new chromatographic analytical method to resolve the problem. The chromatogram are shown in figure-4.a.8.the peaks of the degradation products were well resolved, shown in fig-3a.21 The degradation study thereby indicated that Irinotecan hydrochloride were stable to chemical oxidation study, dry heat and alkali hydrolysis while it was highly susceptible to alkali hydrolysis.acid and thermal degradation study tried by Kono et al and others Figure -4. A.12. A chromatogram of the Irinotecan Hydrochloride alkali degradation. 312

19 4.A.5. Assay method development and Validation of Cyclophosphamide 4.A.5.1. HPLC method development and optimization In present investigation the main target for the development of chromatographic method was to get the reliable method for the quantification of Cyclophosphamide from bulk drug and which will be also applicable for the degradable products. 55 It was also observed that few HPLC and UV methods have been reported for estimation of Cyclophosphamide from plasma which are sophisticated, but time consuming. The present study was aimed at development of speedy and cost effective HPLC technique for determination of Cyclophosphamide as bulk and in dosage forms. The chromatographic method was optimized by changing various parameters, such as the mobile phase composition, ph of the buffer used in the mobile phase. Retention time and separation of peak of Cyclophosphamide were dependent on ph of the buffer and the percentage of methanol. Various blends of solvent systems in varying proportions were tried as mobile phase by Alsarra et al and others Different mobile phases were tried, but satisfactory separation and good symmetrical peak were obtained with the mobile phases containg 800 ml of water and 200 ml methanol mixed filtered and degased and column temperature was maintained at 25 C have better peak shape. The Column used Hypersil BDS C8, 250 x 4.6 mm, 5µm found to comparatively better and gave the graph with a much better peak shape at retention time 6.21 min. 4.A.5.2. Method validation Validation is required for any new or amended method to ensure that it is capable of giving reproducible and reliable results, when used by different operators employing the same equipment in the same or different laboratories.the analytical method was validated as per ICH guidelines with respect to parameters such as linearity, precision, accuracy, specificity, Forced degradation and robustness. 4.A.5.3. System precision: "The precision of an analytical method is the degree of agreement among individual test results obtained when the method is applied to multiple sampling of a homogenous sample. It is a measure of the reproducibility of the whole analytical method (including sampling, sample preparation and analysis) under normal operating circumstances. It can be determined by using the method to assay a sample for a sufficient number of times to obtain statistically valid results 313

20 and is then expressed as the relative standard deviation. In the present study Standard solution of Cyclophosphamide was prepared as per testing procedure and injected into the HPLC system in six replicates. The values of % relative standard deviation 0.11 (NMT 2.0%) for peak area obtained in six replicate injections are reported in Table-3.A.5.1. In our finding the the low value of relative standard deviation attributes that the method is robust.similar results are also reported by different researchers Casale et al during their studywhich is an indicative of the equipment used for the study worked correctly for the developed analytical method, and being highly repetitive Figure -3.A.13. A chromatogram of the Cyclophosphamide Standard 4.A.5.4. Linearity Linearity is determined by calculating the regression line using a mathematical treatment of the results (ie least mean squares) vs analyte concentration. In our present investigation a linear study identifies a specified concentration range where analytes response is linearly proportional to the concentration. The standard curve found to be linear over the concentration range of ppm. The equation of the standard curve relating the peak area to the Cyclophosphamide concentration in this range was y = 699x The drug showed good linearity in the range of ppm with coefficient of correlation value for peak area (Table-3.A.5.2). Our findings are in good aggrement with the work published earlier by Compagnon et al

21 Figure : 4. A.14. Linearity graph of cyclophosphamide y = 699x R² = A.5.5. Accuracy Accuracy indicates the deviation between the mean value found and the true value. lt is determined by applying the method to samples to which known amounts of analyte are added, And are analysed against standard and blank solutions to ensure that no interference exists. The accuracy is then calculated from the test results as a percentage of the analyte recovered by the assay.. In the present study to determine the accuracy of the method three samples were used. The samples chosen to represented the entire range of the standard curve i.e lower, middle and higher concentration of the range. Recovery studies were also carried after addition of standard drug solution at three different levels i.e. 50 %, 100 %, and 150 % to pre-analyzed sample solution for conformation of methods accuracy 61. The results are given in table-3.a.5.3, 3.A.5.4 and 3.A A.5.6. Robustness "The robustness of an analytical procedure is a measure of its capacity to remain unaffected by small, but deliberate variations in method parameters and provides an indication of its reliability during normal usage". 62 In present investigation the percentage recovery of Cyclophosphamide was good under most conditions and didn t showed no significant change when the critical parameters were modified. 315

22 The tailing factor for Cyclophosphamide was always less than 2.0 and well separated under all the changes carried out. Considering the modifications in the system suitability parameters and the specificity of the method it can conclude that the method is robust. Robustness parameter flow plus,flow minus, Temperature plus and Temperature minus results are given in table- 3.A.5.6, 3.A.5.7, 3.A.5.8 and 3.A A.5.7. Forced degradation : Analytical specificity of a method may be defined as the ability to measure accurately and specifically the analyte in the presence of components that may be expected to be present in the sample matrix.specificity for an assay ensures that the signal measured comes from the substance of interest, and that there is no interference from excipient degradation products and/or impurities. 63 In our present study the forced degradation of Cyclophosphamide under different stress condition such as acid, alkali, peroxide,thermal and water according to ICH guideline are reported in table- 3.A However this is the first time reported that 12.44% degradation observed in 0.1 N NaOH. Typical chromatogram show in figure-4.a.10 The peaks of the degradation products were well resolved. The degradation study thereby indicated that Cyclophosphamide was stable to chemical Our findings are in good aggrement with the work published earlier for different drug by Arayne et al and others oxidation study, dry heat and alkali hydrolysis while it was highly susceptible to alkali hydrolysis. Figure -4. A.15. A chromatogram of the Cyclophosphamide alkali degradation. 316

23 4.A.6. Assay method development and Validation of Thiamine Hydrochloride 4.A.6.1. HPLC method development and optimization In our present work the main target for the development of chromatographic method was to get the reliable method for the quantification of Thiamine hydrochloride from bulk drug and which will be also applicable for the degradable products. HPLC method by Thomas 69 and UV methods have been reported for estimation of Thiamine hydrochloride which are sophisticated, but time consuming. UV assay method reported by Yantih et al and others The present study was aimed at development of speedy and cost effective HPLC technique for determination of Thiamine hydrochloride as bulk and in dosage forms. The chromatographic method was optimized by changing various parameters, such as the mobile phase composition, ph of the buffer used in the mobile phase. Retention time and separation of peak of Thiamine hydrochloride were dependent on ph of the buffer and the percentage of methanol. Various blends of solvent systems in varying proportions were tried as mobile phase 73. Different mobile phases were tried, but satisfactory separation and good symmetrical peak were obtained with the mobile phases 0.01 M Ammonium acetate buffer adjust P H = 4.5 with acetic acid. 100 ml of buffer,600 ml acetonitrile and 300 ml of methanol mixed filtered and degased.the Column used Water Symmetry C18(250X4.6),5 m found to comparatively better and gave the graph with better gaussian shape at retention time min. 4.A.6.2. Method validation Method validation of analytical procedures is based on the four most common types of analytical procedures:- Identification tests,quantitative tests for impurities' content,limit tests for the control of impurities, Quantitative tests of the active moiety in samples of drug substance or drug product or other selected component(s) in the drug product. 20 The analytical method was validated as per ICH guidelines with respect to parameters such as linearity, precision, accuracy, specificity, forced degradation and robustness. 4.A.6.3. System precision: In the present findings Standard solution of Thiamine hydrochloride was prepared as per testing procedure and injected into the HPLC system in six replicates. The values of % relative standard deviation 0.08 (NMT 2.0%) for peak area obtained in six replicate injections are reported in Table-3.A.6.1. thus showing that the equipment used for the study worked correctly for the 317

24 developed analytical method, and being highly repetitive. In our finding the low value of relative standard deviation attributes that the method is robust.similar results are also reported by different researchers during their study Amidzic et al 74. Figure -3.A.16. A chromatogram of the Thiamine Hydrochloride standard Prepration. 4.A.6.4. Linearity Analytical linearity study identifies a specified concentration range where analytes response is linearly proportional to the concentration. In our finding the standard curve found to be linear over the concentration range of ppm. The equation of the standard curve relating the peak area to the Thiamine Hydrochloride concentration in this range was y = 733x+1389 The drug showed good linearity in the range of ppm with coefficient of correlation value for peak area (Table-3.A.6.2). Although the initial results obtained in this study are very promising. Figure- 4. A.17.Linearity graph of Thiamine Hydrochloride y = 733x R² =

25 4.A.6.5. Accuracy Accuracy is popularly used to describe the measure of exactness of an analytical method, or the close of an agreement between the value, which is accepted as a conventional, true value or as an accepted reference value, and the value found.it is properly a qualitative concept and the correct term is 'bias'. In present investigation to check the accuracy of the method, recovery studies were carried after addition of standard drug solution at three different levels i.e. 50 %, 100 %, and 150 % to pre-analyzed sample solution for conformation of methods accuracy 75. The results are given in table-3.a.6.3, 3.A.6.4 and 3.A.6.5. Hence this present study investigates the various abilities. 4.A.6.6. Robustness In our finding the percentage recovery of Thiamine hydrochloride was good under most conditions and didn t show any significant change when the critical parameters were modified. The tailing factor for Thiamine hydrochloride was always less than 2.0 and it was well separated under all the changes carried out. Considering the modifications in the system suitability parameters and the specificity of the method it can conclude that the method is robust. Robustness parameter flow plus,flow minus, Temperature plus and Temperature minus results are given in table-3.a.6.6, 3.A.6.7, 3.A.6.8 and 3.A.6.9. Our findings are in good aggrement with the work published earlier by Ditjen et al A.6.7. Forced degradation : Selectivity is the ability to measure accurately and specifically the analyte in the presence of components that may be expected to be present in the sample matrix. In present investigation the forced degradation of Thiamine hydrochloride under different stress condition such as acid, alkali, peroxide,thermal and water according to ICH guideline shown in table- 3.A.6.10.However this present study investigates the various abilities,in present investigation 11.89% degradation observed in 0.2 N NaOH. Typical chromatogram of degredable compound are shown in figure-4.a.12 The peaks of the degradation products were well resolved. The degradation study thereby indicated that Thiamine hydrochloride was stable to chemical oxidation study, dry heat and acid hydrolysis while it was highly susceptible to alkali hydrolysis shown in figure. Our findings are in good aggrement with the work published earlier by Ibrahim et al

26 Figure- 4. A.18.A chromatogram of the Thiamine Hydrochloride alkali degradation 320

27 4.A.7. Assay method development and Validation of Topotecan Hydrochloride 4.A.7.1. HPLC method development and optimization In present investigation the Topotecan is freely soluble in isopropyl alcohol. The drug can be separated on a Inertsil ODS 3V C18(250X4.6)mm,5µ column in reverse phase mode The main target for the development of chromatographic method was to get the reliable method for the quantification of Topotecan hydrochloride from bulk drug and which will be also applicable for the degradable products. We also observed a trend where few HPLC and UV methods have been reported for estimation of Topotecan hydrochloride which are sophisticated, but time consuming. The present study was aimed at development of speedy and cost effective HPLC technique for determination of Topotecan hydrochloride as bulk and in dosage forms. The chromatographic method was optimized by changing various parameters, such as the mobile phase composition, ph of the buffer used in the mobile phase. Retention time and separation of peak of Topotecan hydrochloride were dependent on ph of the buffer and the percentage of methanol. Various blends of solvent systems in varying proportions were tried as mobile phase by Hsiang et al and others Different mobile phases were tried, but satisfactory separation and good symmetrical peak were obtained with the mobile phases 0.02M Potassium dihydrogen phosphate buffer ph = 3.0 with orthophosphuric acid, 300 ml of buffer and 700 ml acetonitrile are mixed,filtered and degassed.the column temperature were maintained at 35 C and gave the graph with better gaussian shape at retention time min. 4.A.7.2. Method validation The objective of validation of an analytical procedure is to demonstrate that it is suitable for its intended purpose. To meet current pharmaceutical regulatory guidelines i.e. USP, ICH and EP, a number of criteria such as specificity, linearity, precision, accuracy, sensitivity and robustness must be investigated in order to validate analytical methods. 4.A.7.3. System precision: Precision was carefully tested,system suitability test as an integral part of method development was used to ensure adequate performance of the chromatographic system. Retention time (RT), number of theoretical plates (N) and tailing factor (T).Standard solution of Topotecan hydrochloride was prepared as per testing procedure and injected into the HPLC system in six replicates. The values of % relative standard deviation 0.10 (NMT 2.0%) for peak area obtained 321

28 in six replicate injections were reported in Table-3.A.7.1. In our finding the the low value of relative standard deviation attributes that the method is robust.similar results are also reported by different research during their study Underberg et al 81.The present study reveals that the equipment used for the study worked correctly for the developed analytical method, and being highly repetitive. Figure -3.A.19. A chromatogram of the Topotecan Hydrochloride standard prepration 4.A.7.4. Linearity. Linearity is determined by calculating the regression line using a mathematical treatment of the results (i.e least mean squares) vs analyte concentration. In the present findings a linear study identifies a specified concentration range where analytes response is linearly proportional to the concentration. The standard curve found to be linear over the concentration range of ppm. The equation of the standard curve relating the peak area to the Topotecan Hydrochloride concentration in this range was y = 812x This is an important observation. Therefore,in this thesis, developments of new chromatographic analytical methods were established to solve this problem. The drug showed good linearity in the range of ppm with coefficient of correlation value for peak area (Table-3.A.7.2). 322

29 Figure- 4. A.20.Linearity graph of Topotecan Hydrochloride y = 812x R² = A.7.5. Accuracy Analytical accuracy, sometimes also referred to as recovery is an indicator of the trueness of the test measurements. To determine the accuracy of the method three quality control samples were used. The samples chosen were such to represent the entire range of the standard curve i.e. lower, middle and higher concentration of the range In present investigation to check the accuracy of the method, recovery studies were conducted after addition of standard drug solution at three different levels i.e. 50 %, 100 %, and 150 % to pre-analyzed sample solution Hence these evidence support the hypothesis that result are good aggriments with Pearson et al The results are given in table-3.a.7.3, 3.A.7.4 and 3.A A.7.6. Robustness The ICH guidelines also recommend that "one consequence of the evaluation of robustness should be that a series of system suitability parameters (e.g. resolution tests) is established to ensure that the validity of the analytical procedure is maintained whenever used". 84 In the present findings the percentage recovery of Topotecan hydrochloride was good under most conditions and didn t show any significant change when the critical parameters were modified. The tailing factor for Topotecan hydrochloride was always less than 2.0 and it was well separated 323

30 under all the changes carried out Considering the modifications in the system suitability parameters and the specificity of the method it can conclude that the method is robust. Robustness parameter flow plus,flow minus, Temperature plus and Temperature minus results are given in table-3.a.7.6, 3.A.7.7, 3.A.7.8 and 3.A A.7.7. Forced degradation : Selectivity is the ability to measure accurately and specifically the analyte in the presence of components that may be expected to be present in the sample matrix.our present work the forced degradation of Topotecan hydrochloride under different stress condition such as acid, alkali, peroxide,thermal and water according to ICH guidline shown in table- 3.A.7.10.In present findings 18.78% degradation observed in 0.5 N NaOH. Typical chromatogram of degredable compound show in figure-4.a.14. The peaks of the degradation products were well resolved The degradation study thereby indicated that Topotecan hydrochloride was stable to chemical oxidation study, dry heat and alkali hydrolysis while it was highly susceptible to alkali hydrolysis. These results facilitate the detection of that impurity in presence of the main drug by using the developed method. Figure- 4. A.21. A chromatogram of the Topotecan Hydrochloride alkali degradation 324

31 4.A.8. Assay method development and Validation of Tenofovir Disoproxil fumarate 4.A.8.1. HPLC method development and optimization In present investigation the main target for the development of chromatographic method was to get the reliable method for the quantification of Tenofovir Disoproxil fumarate from bulk drug and which will be also applicable for the degradable products. This is an important observation few HPLC and UV methods have been reported for estimation of Tenofovir Disoproxil fumarate which are sophisticated, but time consuming. The present study was aimed at development of speedy and cost effective HPLC technique for determination of Tenofovir Disoproxil fumarate as bulk and in dosage forms. The chromatographic method was optimized by changing various parameters, such as the mobile phase composition, ph of the buffer used in the mobile phase. Retention time and separation of peak of Tenofovir Disoproxil fumarate were dependent on ph of the buffer and the percentage of methanol. Various blends of solvent systems in varying proportions were tried as mobile phase by Sweetman et al Different mobile phases were tried, but satisfactory separation and good symmetrical peak were obtained with the mobile phases 0.01M Potassium dihydrogen phosphate buffer ph = 4.5 with orthophosphuric acid 900 ml buffer and 100 ml acetonitrile mixed, filtered anddegassed.the column temperature was maintained at 25 C. Column used are Inertsil ODS 3V C18(150X4.6)mm,5µ found to comparatively better and gave the graph with better gaussian shape at retention time min. 4.A.8.2. Method validation The Method was validated based on the International Conference on Harmonization (ICH) Guidelines The method validation parameters checked were specificity, linearity, accuracy, precision, limit of detection, limits of quantitation and robustness. The analytical method was validated as per ICH guidelines with respect to parameters such as linearity, precision, accuracy, specificity,forced degradation and robustness 4.A.8.3. System precision: In present investigation Tenofovir Disoproxil fumarate was prepared as per testing procedure and injected into the HPLC system in six replicates. The values of % relative standard deviation 0.14 (NMT 2.0%) for peak area obtained in six replicate injections are reported in Table-3.A.8.1. In our finding the the low value of relative standard deviation attributes that the method is robust.similar results are also reported by different researchers during their study

32 thus showing that the equipment used for the study worked correctly for the developed analytical method, and being highly repetitive 96. Figure -4.A.22. A chromatogram of the tenofovir Desoproxill fumarate standard 4.A.8.4. Linearity Linearity corresponds to the capacity of the method to supply results directly proportional to the concentration of the substance being determined within a certain interval of concentration A linear study identifies a specified concentration range where analytes response is linearly proportional to the concentration. In present findings the standard curve found to be linear over the concentration range of ppm. The equation of the standard curve relating the peak area to the tenofovir Desoproxill fumarate concentration in this range was y = 712x The drug showed good linearity in the range of ppm with coefficient of correlation value The linearity was evaluated by linear regression analysis calculated by the least square method (Table-3.A.8.2). Our findings are in good aggrement with the earlier reported work on other drugs by Gish et al