Application of Aspects of Green Chemistry on Pharmaceutical Analysis

Transcription

1 Application of Aspects of Green Chemistry on Pharmaceutical Analysis Thesis Presented for the fulfillment of the degree of Ph.D. In Pharmaceutical Sciences (Analytical Chemistry) BY SamahSabrySaadAbd El-Latif B.Sc. Pharmaceutical sciences, 2001, Misr University For Science and Technology Master degree in pharmaceutical sciences (Analytical Chemistry), 2010, Cairo University Under the Supervision of Prof. Dr. Laila El-SayedAbd El Fattah Professor and Head of Pharmaceutical Analytical Chemistry Department & Vice Dean of Faculty of Pharmacy Misr University for Science & Technology Prof. Dr. MaissaYacoub Youssef Professor of Analytical Chemistry Faculty of Pharmacy Cairo University Dr. EmanSaadELzanfaly Associate Professor of Analytical Chemistry Faculty of Pharmacy Cairo University Dr. Maha Abdel-MonemHegazy Associate Professor of Analytical Chemistry Faculty of Pharmacy Cairo University Faculty of Pharmacy CairoUniversity (2016) 1

2 Abstract Application of Aspects of Green Chemistry on Pharmaceutical Analysis The introduction of sustainable development concept to analytical laboratories has recently gained interest, however most of the conventional analytical methods do not consider either the effect of the used chemicals or the amount of produced waste on the environment. The aim of this work was to proof that conventional methods can be replaced by greener ones with the same analytical parameters. The suggested methods were designed so that they neither use nor produce harmful chemicals, and to produce minimum waste so as to be used in routine analysis without harming the environment. This was achieved by firstly, developing green HPLC methods using green mobile phases and short run times Four mixtures were chosen as model for this study, namely, Clidinium bromide / Chlordiazepoxide hydrochloride, Phenobarbitone /Pipenzolate bromide, Mebeverine hydrochloride / Sulpiride and Chlorphenoxamine hydrochloride /Caffeine /8-Chlorotheophylline either in their bulk powder or in their dosage forms. The methods were validated with respect to linearity, precision, accuracy, system suitability, and robustness. Secondly, Four green spectrophotometric methods were developed for determination of Clidinium bromide / Chlordiazepoxide hydrochloride and Mebeverine hydrochloride / Sulpiride in a binary mixtures. Lastly, Ion selective electrode methods were developed for determination of each of Clidinium bromide and Trifluerazine hydrochloride. The developed methods were compared to the reported conventional HPLC methods regarding their greenness profile. The suggested methods were found to be greener, more time and solvent saving than the reported ones; hence they can be used for routine analysis of the studied mixtures without harming the environment. 2

3 KEYWORDS: Green, high performance liquid chromatography,spectrophotometric, ion selective electrode,clidinium bromide, Chlordiazepoxide hydrochloride, Phenobarbitone, Pipenzolate bromide, Mebeverine hydrochloride, Sulpiride, Chlorphenoxamine hydrochloride, Caffeine /8-Chlorotheophylline, Trifluerazine hydrochloride. Introduction: I.A.1. Green chemistry The term Green chemistry was first introduced by Paul Anastasin 1990s and was defined as the design of chemical products and processes that reduce or eliminate the use and generation of hazardous compounds. (1) It is considered a recently emerged approach for designing chemical products and processes in a way that results in marked reduction or elimination either the use and/or the production of hazardous materials and so become more environmentally friendly. Green chemistry is a pro-active approach which helps in prevention of pollution through targeting at the design stage, before it even begins. Application of such approach results in a marked decrease in waste, hazards and cost. (1) I.A.2. Historical timeline of green chemistry In 1991, PaulAnastas coined the term green chemistry in the 'Green Chemistry Program' introduced by the United States Environmental Protection Agency.Four years later, an annual award was established for achievements in the application of green chemistry principles. In 1997, the green chemistry institute Environmental Protection Agency (EPA) started its work in USA where contacts between governmental 3

4 agencies, industrial corporations and university research centers with the aim of developing and implementing new technologies. In the same year, the first international green chemistrysymposium took place. While in 2003, the first national conference devoted to green chemistry was held in Poland. (2) I.A.3. Principles of green chemistry The US environmental protection agency introduced a guideline to create more environmentally benign products and processes through the definition of 12 principles that could be considered as a rule of thumb for how sustainability can be achieved in the production of chemicals. (1) These principles are summarized as follows: 1.Prevention; it is better to prevent waste than to treat or clean up waste after it has been formed. 2.Atom economy; synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product. 3.Less hazardous chemicals synthesis; whenever practicable, synthetic methodologies should be designed to use and generate substances that possess little or no toxicity to human health and the environment. 4.Designing safer chemicals; chemical products should be designed to preserve efficacy of the function while reducing toxicity. 5.Safer solvents and auxiliaries; the use of auxiliary substances (solvents, separation agents, etc.) should be made unnecessary whenever possible and, when used, innocuous. 4

5 6.Design for energy efficiency; energy requirements should be recognized for their environmental and economic impacts and should be minimized. Synthetic methods should be conducted at ambient temperature and pressure. 7.Use of renewable feed stocks; a raw material or feedstock should be renewable rather than depleting whenever technically and economically practical. 8.Reduce derivatives; unnecessary derivatization (blocking group, protection/deprotection, temporary modification of physical/chemical processes) should be avoided whenever possible. 9.Catalysis; catalytic reagents (as selective as possible) are superior to stoichiometric reagents. 10.Design for degradation; chemical products should be designed so that at the end of their function they do not persist in the environment and instead break down into innocuous degradation products. 11.Real-time analysis for pollution prevention; analytical methodologies need to be further developed to allow for real-time in-process monitoring and control prior to the formation of hazardous substances. 12.Inherently safer chemistry for accident prevention; substance and the form of a substance used in a chemical process should be chosen so as to minimize the potential for chemical accidents, including releases, explosions, and fires. 5

6 I.A.4. Green analytical chemistry Analytical chemistry takes a special place in the green chemistry concept. Green Analytical Chemistry aimed to the development of greener analytical methods through minimizing sample preparation, handling, solvent and reagent consumption, energy consumption and waste. By this way, the developed methods reduce the undesirable environmental side effects of chemical analysis, while preserving the accuracy, sensitivity, selectivity and precision of the analytical determination. The application of green analytical chemistry is achieved through the use of instrumental methods instead of wet chemistry where the miniaturization and automation are among the new trends of analytical chemistry. (3) Analytical chemistry has been used since the 1960s to monitor pollutants from environmental and food samples through reducing the use of solvents in sample preparation and miniaturization of columns. However, the concept of green analytical chemistry was first introduced by Paul Anastas in 1999 (4) which necessitate not only monitoring of environmental pollutants but also increasing the greenness of analytical methodologies. From the 12 principles of green chemistry, 6 principles suits for green analytical chemistry were extracted: 1. Prevent or reduce the formation of waste, for instance, by using smaller inner diameter columns in chromatography. 2. Use less toxic/environmentally burdensome chemicals and solvents. 3. Design energy-efficient analytical systems and methodologies. 4. Avoid the use of chemical catalysts, derivatization reagents, and other auxiliary substances. 6

7 5. In situ analysis is better than off-line analysis. 6. Use safer chemistry to prevent accidents such as explosions and fires. There are several review articles (2, 5, 6) as well as a few books describing the area of green analytical chemistry. (7, 8) I.A.5. Assessment of green solvents Assessment of analytical methods should be a natural development trend in chemistry. As previously mentioned, some of the principles of green chemistry are directly related to analytical chemistry and should be taken into consideration while assessing an analytical method. (9) In order to assess the greenness of the used solvents, several tools were used such as: 1-The EPA s toxic release inventory (TRI) method (9),a reagent or solvent is considered hazardous substances if it is listed in the TRI table. 2-The environment, health &safety (EHS) method (9), assessment of the impact on health and the environment which is a screening method that aims to identify potential hazards of chemicals. ESH method indicates low overall scores were found for methyl acetate, ethanol and methanol, which inherit particularly low environmental hazards and relatively low 7

8 health hazards as shown in Figure1. Figure 1: ESH assessment of organic solvents (9) 3-The life-cycle assessment (LCA) method (9), that can be used for a detailed assessment of emissions to the environment as well as resource use over the full life-cycle of a solvent, including the production, the use, potential recycling, and the disposal as shown in Figure 2. Figure 2: Life-cycle assessment of organic solvents (9) 8

9 4-American Chemical Society Green Chemistry Institute Pharmaceutical Roundtable (ACS GCIPR) green solvents list shown in Figure 3. (10) Figure 3: Green Solvents List (ACS) (10) The green solvents list introduced by ACS includes solvents which are annotated with information about health and safety profile, and the environmental problems associated with the use and disposal. It contains information data (molecular formula, CAS No.) and coded with numbers from 1 to 10 (the higher the number the higher the hazard or toxicity) for health and safety, and environmental hazards for air, water and waste. Solvents with the greatest disposal/pollution problems are colored brown, and those with lesser problem are colored green. (10) I.A.6. Assessment of analytical method greenness 1- To quantitate the greenness of an analytical method, the greenness profile symbol (figure 4) has been proposed by the environmental protection agency (EPA) and was introduced in the National Environmental Methods Index (NEMI) database. (11) The profile criteria for this method was based on four key terms as shown in Figure 4. 9

10 Figure 4: NEMI pictogram. The field is green if the requirements of criterion are fulfilled. (11) To quantify the greenness of an analytical method, the greenness profile symbol (Figure 4) has been proposed. Greenness profiles have been added to some analytical methods databases so that one can look at a method's rating and see how green it is. The profile criteria are summarized by four key terms Where, PBT [A chemical used in the method is listed as Persistant, Bioaccumulative, and Toxic, as defined by the EPA s TRI].Hazardous [A chemical used in the method is listed on the TRI or on one of the RCRA s, (The Resource Conservation and Recovery Act) hazardous waste lists]. Corrosive [ph during the analysis is less than 2 or greater than 12].Waste [Waste amount generated is greater than 50 g].each quadrant is either "green" or "blank" depending on the method fit to that particular criterion. Thus, by examining the overall profile, an analyst can quickly compare the greenness of method. (11) An improvement to the NEMI pictogram was proposed by de la Guardia and Armenta. (12) These authors suggested that each of the fields should be colored using a three degree scale; red for non-environmentally friendly analysis, yellow for moderate and green for environmentally 11

11 benign analysis. This modification makes the NEMI procedure assessment more quantitative. 2-The analytical eco-scale is an approach to the assessment of environmental impact of analytical methods. The result is a score that is calculated by subtracting penalty points from the basis of 100. The penalty points are assigned for high amounts and high hazards connected with utilization of chemicals, high energy consumption, occupational hazards and generation of wastes. A final result is a number less than 100 ( ideal green analysis ) by a number of penalty points, if the score is above 75, so the analysis is considered green. (13) 3- Environmental assessment tool (EAT) was developed for HPLC methods using EHS data by Gaberet al. (14). This is a software tool which was called HPLC-EAT; it takes into consideration the environmental, health and safety issues for all solvents involved in the chromatographic method, and calculates a total score that can be used for comparison of the greenness of different methods. It was successfully applied for a set of different HPLC methods. The performance of the tool was validated and it was further combined with another free software Eco-solvent tool to perform life cycle assessments of waste disposal. So, it can be routinely used in method development to calculate the greenness beside the conventional standards of accuracy, robustness and reproducibility. I.A.7. Applications of aspects of green analytical chemistry in pharmaceutical analysis Recently, the importance of application of green analytical chemistry in pharmaceutical analysis was emerged with the intent of replacement of the conventional methods with more green ones. 11

12 The green analytical methods for determination of some pharmaceutical compounds includes the use of electrochemical (15), spectrophotometric (16, 17) and chromatographic ones. (18-20) I.A.8. Aim of thesis The aim of this thesis was to highlight the impact of applying the concepts of green analytical chemistry through the development of different methods (chromatographic, spectrophotometric and potentiometric) in pharmaceutical analysis and prove that conventional methods can be replaced by greener ones with the same analytical performance characteristics but more eco-friendly. This was achieved by developing validated green analytical methods for analysis of different pharmaceutical formulations. The suggested methods were designed so that they neither use nor produce harmful chemicals, also not to be corrosive and to produce minimum waste so as to be continuously used in routine analysis and quality control laboratories without harming the environment. The developed methods were compared to other reported methods regarding their greenness profile. In order to achieve our goal, different pharmaceutical formulations were selected namely, Clidinium Bromide (CB) and Chlordiazepoxide Hydrochloride (CD), Phenobarbitone (PB) and Pipenzolate Bromide (PZ), Mebeverine Hydrochloride (MB) and Sulpiride (SUL),Chlorphenoxamine Hydrochloride (CPH), Caffeine (CAF), and 8- Chlorotheophylline (CTH) and Trifluperazine Hydrochloride(TFP). Aim of work: The aim of this work is to highlight the impact of applying green analytical chemistry in pharmaceutical analysis and prove that 12

13 conventional methods can be replaced by greener ones with the same analytical performance characteristics but more eco-friendly. Different analytical techniques were employed including High Performance Liquid Chromatographic, Ion Selective Electrode and Spectrophotometry methods for the analysis of different pharmaceutical formulations. The suggested methods were designed so that they neither use nor produce harmful chemicals, also not to be corrosive and to produce minimum waste so as to be continuously used in routine analysis and quality control laboratories without harming the environment. The developed methods were compared to reported conventional methods regarding their accuracy, precision and greenness profile. Summary: This thesis consists of four parts in addition to References and both English and Arabic Summaries. Part I: General Introduction to Green Analytical Chemistry and Literature Review of the Studied Drugs Section A:General Introduction to Green Analytical Chemistry It represents an introduction to green chemistry and green analytical chemistry. It also contains a brief overview of historical timeline of green chemistry. It gives an idea about the assessment of solvents and analytical method greenness. Some applications of aspects of green analytical chemistry in pharmaceutical analysis are mentioned including electrochemical, spectrophotometric, and chromatographic ones. 13

14 Section B:Literature Review of the Studied Drugs This section includes the literature review of the studied drugs. These drugs are Clidinium Bromide, Chlordiazepoxide Hydrochloride, Phenobarbitone, Pipenzolate Bromide, Mebeverine Hydrochloride, Sulpiride, Chlorphenoxamine Hydrochloride, Caffeine, 8-Chlorotheophylline and Trifluperazine Hydrochloride. For each of them, chemistry and pharmacological action and an updated record of the previous analytical studies were discussed. These reported methods includes different techniques used for their analysis in pure samples either singly or in combinations, pharmaceutical dosage forms and biological matrices. Part II:Application of Aspects of Green Analytical Chemistry on DrugAnalysis Using High Performance Liquid Chromatograhic Methods This part is divided into four sections. Section A: Green HPLC Method for Determination of Clidinium Bromide and Chlordiazepoxide Hydrochloride In this section, Green HPLC method was developed for determination of Clidinium bromide in its binary mixture with ChlordiazepoxideHydrochlorideusing Zorbax SB- C18 HPLC column (4.6mm x 75mm, i.d., 3.5µm) as stationary phase, Ethanol : Water, ( 50 : 50, v/v) as mobile phase with flow rate of 0.5 ml/min. The detection was carried out using an UV- detector at 210nm. Section B:Green HPLC Method for Determination of Phenobarbitone and Pipenzolate Bromide 14

15 In this section, Green HPLC method was developed for determination of Phenobarbitone in a binary mixture with Pipenzolate Bromide using Zorbax SB- C18 HPLC column (4.6mm x 75mm, i.d., 3.5µm) as stationary phase, Ethanol : Water, ( 50 : 50, v/v) as mobile phase with flow rate of 0.5 ml/min. The detection was carried out using an UV- detector at 220nm. Section C: Green HPLC Method for Determination of Mebeverine Hydrochloride and Sulpiride In this section, Green HPLC method was developed for determination of MebeverineHydrochloridein a binary mixture with Sulpiride using Zorbax SB- C18 HPLC column (4.6mm x 75mm, i.d., 3.5µm) as stationary phase, Ethanol : Water, ( 94.5 : 5.5, v/v) as mobile phase with flow rate of 0.8 ml/min. The detection was carried out using an UV- detector at 220nm. Section D:Green HPLC method for Determination of Caffeine, 8- Chlorotheophylline and Chlorphenoxamine Hydrochloride In this section, Green HPLC method was developed for determination of Caffeine, 8- Chlorotheophylline and ChlorphenoxamineHydrochloridein a ternary mixture using a Polaris SI (4.6 mm x 50 mm, i.d., 3 µm) as stationary phase, Ethanol ( 100%) as mobile phase with flow rate of 0.4 ml/min. All measurements were carried out for drugs each at its λ max to attain the maximum sensitivity, using DAD permits achieving this goal (270.4, and nm for Caffeine, 8- Chlorotheophylline and ChlorphenoxamineHydrochloride, respectively. In this part, the obtained results were statistically compared with those obtained by applying a reported HPLC method. Also, were compared to the reported conventional HPLC methods regarding their greenness profile. 15

16 Part III: Application of Aspects of Green Analytical Chemistry on Drug Analysis Using Potentiometric Analysis (Ion Selective Electrodes) This part is divided into two sections. Section A: Potentiometric Determination of Clidinium Bromide by Ion Selective Electrodes In this section, a green potentiometric method using two ion selective membrane sensors was proposed for determination of Clidinium Bromide either in its pure substance or drug product. In sensor (1) was PVC-Carboxylate membrane was used as an electro active substance then of ß- CD was added in sensor (2).Sensor (1) was found to be more selective than (2) while the latter was found to be more sensitive. Statistical student's t-test and F test showed insignificant difference between accuracy and precision between proposed and reported methods. Section B: Potentiometric Determination of Trifluperazine Hydrochloride by Ion Selective Electrodes In this section, a green potentiometric method using two ion selective membrane sensors was proposed for determination of TrifluperazineHydrochlorideeither in its pure substance or drug product. In sensor (1), ß- CD was incorporated with PVC-Carboxylate as electroactive substances in then membrane while in sensor (2), PVC and Sodium Tetraphenyl borate were used, both suggested sensors has almost the same sensitivity and selectivity. Statistical student's t-test and F test showed insignificant difference between accuracy and precision between proposed and official methods. 16

17 Part IV:Application of Aspects of Green Analytical Chemistry on Drug Analysis Using (Spectrophotometric Methods) This part is divided into four sections. Section A:Green Spectrophotometric Determination of Clidinium Bromide and Chlordiazepoxide Hydrochloride by Ratio Difference Spectrophotometric Method In this section, ratio difference spectrophotometric method (RDSM) was used for the quantitative determination of Clidinium Bromide and Chlordiazepoxide Hydrochloridein their pure form, in their laboratory prepared mixtures and in their pharmaceutical dosage form. The spectra of Clidinium Bromide and Chlordiazepoxide Hydrochloride were divided by the absorption spectrum of 3.00 µg/mlof Chlordiazepoxide Hydrochloride and µg/mlof Clidinium Bromide, respectively to obtain the ratio spectra, the amplitudes difference was calculated between 229 and 280 nm for Clidinium Bromideand between 240 and 256 nm for Chlordiazepoxide Hydrochloride. The proposed method was applied for the analysis of Clidinium Bromide and Chlordiazepoxide Hydrochloride over the concentration range of 5-35, 1-15 µg/ml, respectively. The obtained results were statistically compared with those obtained by applying a reported HPLC method. Section B: Green Spectrophotometric Determination of Clidinium Bromide and Chlordiazepoxide Hydrochloride by Mean Centering of Ratio Spectra Method In this section, mean centering of ratio spectra method (MCR) was used for the quantitative determination of Clidinium Bromide and Chlordiazepoxide Hydrochloridein their pure form, in their laboratory prepared mixtures and in their pharmaceutical dosage form. 17

18 The spectra of Clidinium Bromide and Chlordiazepoxide Hydrochloride were divided by the absorption spectrum of 3.00 µg/mlof Chlordiazepoxide Hydrochloride and µg/mlof Clidinium Bromide, respectively to obtain the ratio spectra then these spectra were mean centered and the mean centered values at 300 nm & 312 nm for Clidinium Bromide and Chlordiazepoxide Hydrochloride, respectively were measured. The proposed method was applied for the analysis of Clidinium Bromide and Chlordiazepoxide Hydrochloride over the concentration range of 5-35, 1-15 µg/ml, respectively. The obtained results were statistically compared with those obtained by applying a reported HPLC method. Section C: Green Spectrophotometric Determination of Mebeverine Hydrochloride and Sulpiride by Ratio Difference Spectrophotometric Method In this section, ratio difference spectrophotometric method (RDSM) was used for the quantitative determination of MebeverineHydrochloride andsulpiridein their pure form, in their laboratory prepared mixtures and in their pharmaceutical dosage form. The spectra of MebeverineHydrochloride andsulpiridewere divided by the absorption spectrum of 5.00 µg/mlof Sulpiride and 5.00 µg/mlof Mebeverine Hydrochloride, respectively to obtain the ratio spectra, the amplitudes difference was calculated between and nm for Mebeverine Hydrochloride and between and nm for Sulpiride. The proposed method was applied for the analysis of MebeverineHydrochloride andsulpirideover the concentration range of 1-40, 1-35 µg/ml, respectively. The obtained results were statistically compared with those obtained by applying a reported HPLC method. 18

19 Section D: Green Spectrophotometric Determination of Mebeverine Hydrochloride and Sulpiride by Mean Centering of Ratio Spectra Method In this section, mean centering of ratio spectra method (MCR) was used for the quantitative determination of MebeverineHydrochloride andsulpiridein their pure form, in their laboratory prepared mixtures and in their pharmaceutical dosage form. The spectra of Mebeverine Hydrochloride and Sulpiridewere divided by the absorption spectrum of 5.00 µg/mlof Sulpiride and 5.00 µg/mlof Mebeverine Hydrochloride, respectively to obtain the ratio spectra and then these spectra were mean centered and the mean centered values at 266 nm & nm for Mebeverine Hydrochloride and Sulpiride, respectively were measured. The proposed method was applied for the analysis of Mebeverine Hydrochloride and Sulpirideover the concentration range of 1-40, 1-35 µg/ml, respectively. The obtained results were statistically compared with those obtained by applying a reported HPLC method. This thesis contains 112 references, 44 figures, 60 tables and arabic summary. 19