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اقطاب كرافيت لاغشية متعدد كلوريد الفاينيل جديدة معتمدة على بوليمرات الطبعة الجزيئية للتعيين الجهدي الانتقالي لعقاري الرسبيريدون والكلبينكلامايد
Author name:
همسة منعم ياسين
Supervisor name:
نجوى اسحق عبد الله
General topic:
Chemistry
Specific topic:
Chemistry
Degree:
Doctorate
University:
University of Baghdad
Language:
English
University location:
Baghdad
First pages:
25T1881 - p.pdf
Abstract:
The increasing demand for rugged and robust sensors for the determination of drugs in pharmaceutical formulations and biological samples lead to the development of a new generation of ion selective membrane electrodes depended on molecular imprinting technique.Four graphite coated electrodes of polymers imprinted with two drugs namely Risperidone (Ris.) and Glibenclamide (Glb.) were constructed for the selective determination in their pure forms and pharmaceutical formulations.The study comprised two parts : The first part deals with the synthesis of molecularly imprinting polymers (MIP) and non - imprinting polymers (NIP) by bulk polymerization method using Risperidone and Glibenclamide as templates, acrylic acid (AA) and acrylamide (AAm) as functional monomers, ethylene glycol dimethacrylate (EGDMA) as a cross linker and benzoyl peroxide (BPO) as an initiator.The optimal ratios of (template : monomer : cross linker) which were used in the synthesis of the imprinted polymers were found to be 1 : 4 : 20 for Risperidone MIPs and 1 : 80 : 100 for Glibenclamide MIPs.The second part concerns with the designing of potentiometric sensors for Risperidone and Glibenclamide. The molecularly imprinted and non - imprinted membranes were prepared by dispersing the MIP and NIP particles in di - octyl phthalate (DOP) and di - butyl phthalate (DBP) plasticizers as solvent mediators and then embedded in poly vinyl chloride (PVC) matrix. The mixture was coated as a membrane onto a graphite electrode.The characteristics of the prepared electrodes according to the IUPAC recommendations including slope, linear range, detection limit, life time, response time, working pH range and selectivity were investigated by construction of a calibration curve for each electrode.Ris - MIP electrodes based on (AA) and (AAm) as functional monomers showed a near Nernstian and Nernstian slopes of (55.2and 59.0) mV/decade with a linear concentration range between (1.0×10 - 6 - 1.0×10 - 2) M and (5.0×10 - 7 - 1.0×10 - 2) M, and detection limits (3.3×10 - 7and 2.0×10 - 7) M respectively. The responses of the electrodes were stable in a pH range (4 - 8). The electrodes can be used for (7 and 13) weeks respectively without any divergence in the potential.Ris - MIP membrane based on (AAm) as a monomer was prepared using two kinds of plasticizers, DOP and DBP. The one using DOP exhibited better characteristics comparing with that based on DBP which showed a lower response with a slope of 47.9mV/decade and shorter life time of 3 weeks.On the other hand (Glb.) MIP based electrodes using (AA) and (AAm) as functional monomers showed a near Nernstian responses of ( - 51.5and - 57.7) mV/decade with a linear working range of (1.0×10 - 4 - 1.0×10 - 2) M and (1.0×10 - 5 - 1.0×10 - 3) M, and detection limits of (1.0×10 - 4 and 1.0×10 - 5) M respectively. The life time of these electrodes were (1and 6) weeks respectively. The proposed electrodes could be used in the pH range (2 - 4) with a stable response.Two plasticizers; DOP and DBP were tested during the preparation of Glb - MIP membranes based on (AAm) as a monomer. The (Glb.) membrane using DOP plasticizer exhibited better specifications than that based on DBP which showed a lower response with a slope of - 53.4mV/decade and shorter life time 3 weeks.All of the proposed Ris. - MIP and Glb - MIP sensors have a short response time of ≤ 30 seconds and revealed good selectivity for (Ris.) and (Glb.) over a wide variety of species.The validation of the proposed potentiometric method utilizing these new MIPs electrodes for (Ris.) and (Glb.) was achieved by accuracy and precision test in terms of inter - day (repeated over 3 days) and intra - day (repeated independently three times a day) measurements and calculating RE% and RSD% which is found less than (4 and 2.3046) for (Ris). and less than (4 and 2.3225) for (Glb.) respectively.The most effective electrodes; (Ris.) MIP and (Glb.) MIP based on (AAm) as a functional monomer and DOP as a plasticizer were used in the determination of Ris. and Glb. concentrations in their pharmaceutical formulations (tablets and caplets) obtained from different companies by direct, standard addition and multiple standard addition methods. A spectrophotometric method was also applied as a comparative one. The multiple standard addition method (M.S.A) has exhibited better results over the two other appliedThe recognition binding sites of the four synthesized polymers were studied by applying the rebinding procedure and plotting the adsorption isotherms of each polymer to find out Qmax. The equilibrium dissociation constant was calculated from the slope and the apparent maximum number of binding sites from the y - intercept in the linear Scatchard plot of Q/Cfree vs. Q
