Yekta Özer - Academia.edu (original) (raw)

Papers by Yekta Özer

Research paper thumbnail of 18th European Symposium on Radiopharmacy and Radiopharmaceuticals

EJNMMI Radiopharmacy and Chemistry, 2016

Background: The arginine-glycine-aspartic (RGD) peptide sequence serves as a high-affinity antago... more Background: The arginine-glycine-aspartic (RGD) peptide sequence serves as a high-affinity antagonist of the integrin α v β 3 receptor that plays an important role in tumor angiogenesis. Recently we reported [ 68 Ga]FSC(succ-RGD) 3 , a trimeric RGD peptide, exhibited excellent targeting properties for α v β 3 integrin expression and significant improved tumor uptake compared to monomeric [ 68 Ga]NODAGA-RGD.(1) Here we report the PET imaging properties of [ 68 Ga]FSC(succ-RGD) 3 in different xenograft tumor model and compared them with [ 68 Ga]NODAGA-RGD. Materials and methods: The PET imaging properties of [ 68 Ga]FSC(succ-RGD) 3 were studied in nude mice bearing M21 human melanoma xenografts and human glioblastoma U87MG xenograft tumor. A parallel PET imaging of 68 GaNODAGA-RGD in same mouse bearing U87MG xenograft tumor was performed as a comparison. Results: The static PET image of [ 68 Ga]FSC(succ-RGD) 3 in nude mice showed highly visualized tumors of M21 (positive) whereas nonvisualized tumor of M21-L (negative) tumor xenografts 1 h post injection confirming receptor-specific activity accumulation. The dynamic PET images of [ 68 Ga]FSC(succ-RGD) 3 showed rapid clearance of [ 68 Ga]FSC(succ-RGD) 3 from the circulation while the tumor remained clearly visible. A direct comparison of [ 68 Ga]FSC(succ-RGD) 3 with [ 68 Ga]NODAGA-RGD in nude mice bearing U87MG xenograft tumor using PET/CT resulted comparable target/background ratio (tumor/kidneys ratio = 1.3 and 1.6, tumor/ muscle ratio = 4.9, 5, respectively, 90 min post injection). The time activity curves from dynamic PET data showed an increase of the activity concentration of [ 68 Ga]FSC(succ-RGD) 3 in tumor firstly, then remained almost constant whereas that of [ 68 Ga]NO-DAGA-RGD decreased quickly. The significant enhanced tumor uptake (3.8 vs. 1.6 % ID/g) in addition to the slower washout rate from tumor for [ 68 Ga]FSC(succ-RGD) 3 not only allows the PET EJNMMI Radiopharmacy and Chemistry

Research paper thumbnail of Production and Quality Control of 201TlCl from SPECT Radiopharmaceuticals

Research paper thumbnail of Alternative Applications for Drug Delivery: Nasal and Pulmonary Routes

Springer eBooks, Sep 18, 2007

ABSTRACT For treatment of human diseases, nasal and pulmonary routes of drug delivery are gaining... more ABSTRACT For treatment of human diseases, nasal and pulmonary routes of drug delivery are gaining increasing importance. These routes provide promising alternatives to parenteral drug delivery particularly for peptide and protein therapeutics. For this purpose, several drug delivery systems have been formulated and are being investigated for nasal and pulmonary delivery. These include liposomes, proliposomes, microspheres, gels, prodrugs, cyclodextrins and others. In this chapter, nasal and pulmonary drug delivery mechanisms and some of the relevant drug delivery formulations are evaluated

Research paper thumbnail of The Effect of Radiation on a Variety of Pharmaceuticals and Materials Containing Polymers

Pda Journal of Pharmaceutical Science and Technology, Mar 1, 2012

Research paper thumbnail of Pharmacodynamic Comparison of a Nasal Formulation of Verapamil and Intravenous and Oral Dosage Forms

Drug Development and Industrial Pharmacy, 1996

ABSTRACT Abstract The nasal route has been shown to be effective for the administration of numero... more ABSTRACT Abstract The nasal route has been shown to be effective for the administration of numerous drugs in order to improve drug bioavailability. A nasal gel of verapamil hydrochloride was formulated and evaluated pharmacodynamically in humans, using electrocardiographic results, with comparison to oral and IV routes. Seven volunteers were involved in the study and the pharmacodynamic parameters were evaluated statistically. Experimental nasal gel showed similar pharmacodynamic results with the intravenous route, which is a hint to the reduction in verapamilinduced first-pass metabolism. However, oral route of administration showed a tendency of less efficacy. No reasonable effect of verapamil could be obtained with the placebo group.

Research paper thumbnail of Applications of Light and Electron Microscopic Techniques in Liposome Research

Springer eBooks, Sep 18, 2007

Liposomes and some other vesicular systems are widely used as delivery vehicles for bioactive com... more Liposomes and some other vesicular systems are widely used as delivery vehicles for bioactive compounds. Successful applications of these carrier systems in drug delivery, gene therapy and other health related areas depend on comprehensive understanding of their physical properties including polydispersity and morphology. Variations in size and shape of the carrier systems are indications of their stability and shelf life and can guide scientists in improving the therapeutic formulations. Towards this end microscopic techniques can provide vital information on size, configuration, stability and mechanisms of cellular uptake of particles on micro and nanoscales as discussed in this chapter

Research paper thumbnail of Advers Reactions to Radiopharmaceuticals: Kidney Imaging Radiopharmaceuticals

Research paper thumbnail of Copper-64 Radiopharmaceuticals: An Overview

Research paper thumbnail of Ticari Tc-99m-DTPA radyofarmasötik kitleri üzerine bir kalite kontrol çalışması

Research paper thumbnail of Clinical Applications of Nanosized Drug-Delivery Systems in Lung Cancer Imaging and Therapy

Critical Reviews in Therapeutic Drug Carrier Systems, 2020

Globally, lung cancer is one of the most frequently diagnosed and deadliest types of cancer. Lung... more Globally, lung cancer is one of the most frequently diagnosed and deadliest types of cancer. Lung cancer imaging can be performed using both invasive and noninvasive techniques, including magnetic resonance, positron emission tomography, single photon emission computed tomography, chest radiography, and computed tomography. But nonspecific contrast agents and radiopharmaceuticals are insufficient for early and specific diagnoses and imaging. In the case of lung cancer therapy, conventional therapeutic agents and radiotherapy may cause severe and systemic adverse and toxic effects and fail to eradicate all tumor tissue. Therefore, formulation of novel, targeted, and specific agents is critically important to overcome these challenges. In this review, we summarize lung cancer classification, current methods for lung cancer imaging and therapy, and future options containing nanosized systems for lung cancer imaging and/or therapy.

Research paper thumbnail of Radiolabeled, folate-conjugated liposomes as tumor imaging agents: Formulation and in vitro evaluation

Journal of Drug Delivery Science and Technology, Apr 1, 2019

Cancer is the major burden of disease worldwide. The folate receptor, as a specific tumor target,... more Cancer is the major burden of disease worldwide. The folate receptor, as a specific tumor target, is over-expressed in many types of cancer including ovarian carcinomas, breast, colon, renal, and lung tumors. Nuclear medicine hybrid imaging modalities, such as SPECT/CT, provide both metabolic and anatomic information. Therefore, specific contrast agents are essentially needed. Liposomes are favorable systems with many advantages. The aim of this study was to formulate liposomal imaging agents for molecular tumor imaging by SPECT or SPECT/CT and evaluate their efficacy. Nanosized, polyethyleneglycolated, folate-conjugated and unmodified, diethylenetriaminepentaacetic acid-phosphatidylethanolamine containing, neutral and positively charged liposomes were formulated and characterized by mean particle size, zeta potential, and quantitative determination of the phospholipids in the liposomes. The binding of the synthetized imaging agents to 4T1 breast tumor cells was evaluated by fluorescence microscopy and radioactivity counting. Folate-conjugated neutral and positively charged liposomes were found to be effective as tumor imaging agents exhibiting an almost 3-fold increased uptake and brighter fluorescence microscopy images than unmodified ones in in vitro experiments using 4T1 breast tumor cells. These results could be considered as an important step towards the development of folate-specific agents for tumor imaging by SPECT and SPECT/CT.

Research paper thumbnail of Targeted Alpha Therapy and Nanocarrier Approach

Cancer Biotherapy and Radiopharmaceuticals, Aug 1, 2020

The rates of cancer incidence and mortality are increasing day by day. Although several conventio... more The rates of cancer incidence and mortality are increasing day by day. Although several conventional methods including surgery, chemotherapy, and radiotherapy (RT) exist for cancer treatment, they are insufficient in the eradication of all tumor tissues and have some side-effects such as narrow therapeutic index and serious side-effects to healthy tissues. Moreover, it may probably recur in time due to the survival and spreading of cancerous cells or any possible metastases. Targeted radionuclide therapy is a promising alternative. α particles are ideal for localized cell killing because of their high linear energy transfer and short ranges. However, upon emission of α particles, the daughter nuclides induce a recoil energy to lead decoupling from any chemical bond that may accumulate in normal tissues. Targeted α therapy can also be performed by targeted delivery systems apart from mAb, mAb fragments, peptides, and small molecules for selective tumor therapy. Targeted drug delivery systems have been developed to overcome the limitations of α therapy. Moreover, drug delivery systems are one of the most searched applications in cancer imaging and/or treatment due to their targeting ability to tumor or biocompatibility properties. The aim of this article is to summarize tumor therapy applications, targeted α RT approach, and to review the role of drug delivery systems in the delivery of α particles for cancer therapy and some instances of targeted α-emitting drug delivery systems from the literature.

Research paper thumbnail of Drug Delivery Systems for Imaging and Therapy of Parkinson';s Disease

Current Neuropharmacology, Apr 8, 2016

Background: Although a variety of therapeutic approaches are available for the treatment of Parki... more Background: Although a variety of therapeutic approaches are available for the treatment of Parkinson's disease, challenges limit effective therapy. Among these challenges are delivery of drugs through the blood brain barier to the target brain tissue and the side effects observed during long term administration of antiparkinsonian drugs. The use of drug delivery systems such as liposomes, niosomes, micelles, nanoparticles, nanocapsules, gold nanoparticles, microspheres, microcapsules, nanobubbles, microbubbles and dendrimers is being investigated for diagnosis and therapy. Methods: This review focuses on formulation, development and advantages of nanosized drug delivery systems which can penetrate the central nervous system for the therapy and/or diagnosis of PD, and highlights future nanotechnological approaches. Results: It is esential to deliver a sufficient amount of either therapeutic or radiocontrast agents to the brain in order to provide the best possible efficacy or imaging without undesired degradation of the agent. Current treatments focus on motor symptoms, but these treatments generally do not deal with modifying the course of Parkinson's disease. Beyond pharmacological therapy, the identification of abnormal proteins such as α-synuclein, parkin or leucine-rich repeat serine/threonine protein kinase 2 could represent promising alternative targets for molecular imaging and therapy of Parkinson's disease. Conclusion: Nanotechnology and nanosized drug delivery systems are being investigated intensely and could have potential effect for Parkinson's disease. The improvement of drug delivery systems could dramatically enhance the effectiveness of Parkinson's Disease therapy and reduce its side effects.

Research paper thumbnail of Dtpa Niosomes in Diagnostic Imaging

Research paper thumbnail of Simultaneous Quantification of Paclitaxel and Vinorelbine Encapsulated in Theranostic Nanosized Liposomes

Journal of Analytical Chemistry, Jun 1, 2021

Cancer is one of the major health problems with an increasing incidence and mortality. Although i... more Cancer is one of the major health problems with an increasing incidence and mortality. Although imaging and effective treatment methods are critical issues to prevent cancer mortality, they are inadequate. Therefore, new approaches including combined treatment protocol and nanosized drug delivery theranostic systems are being investigated because of the deficiency of conventional cancer imaging and treatment methods in clinics. Liposomes attract attention in cancer imaging and treatment due to their advantages. In this study, an HPLC method was developed for simultaneous quantification of paclitaxel (PCX) and vinorelbine tartarate (VNB) in co-drug encapsulated theranostic nanosized liposome formulations as an effective cancer imaging and treatment agent. The method was validated according to ICH Analytical Method Validation guideline. According to the validation results, the method was found to be linear (r > 0.999), accurate (bias ≤ 1.8), precise (RSD ≤ 1.8%) and robust (p > 0.05). The developed method was successfully applied to the quantification of PCX and VBN in liposomes for encapsulation efficiency.

Research paper thumbnail of 99mTc-radiolabeled Levofloxacin and micelles as infection and inflammation imaging agents

Journal of Drug Delivery Science and Technology, Apr 1, 2020

Easy and early detection of infection and inflammation is essential for early and effective treat... more Easy and early detection of infection and inflammation is essential for early and effective treatment. In this study, PEGylated micelles were designed and both micelles and Levofloxacin were radiolabeled with 99m TcO 4 to develop potential radiotracers for detection of infection/inflammation. Radiolabeling efficiency, in vitro stability and bacterial binding of 99m Tc-Levofloxacin and 99m Tc-micelles were compared. The aim of this study is to formulate and compare 99m Tc-Levofloxacin and 99m Tc-micelles as infection and inflammation agents having different mechanisms for the accumulation at infection and inflammation site. PEGylated micelles were designed with a particle size of 80 ± 0.7 nm and proper characterization properties. High radiolabeling efficiency was achieved for 99m Tc-Levofloxacin (96%) and 99m Tc-micelles (87%). The radiolabeling efficiency was remained stable with some insignificant alterations for both radiotracers at 25°C for 24 h. Although in vitro bacterial binding of 99m Tc-levofloxacine was higher than 99m Tc-micelles, 99m Tc-micelles may also be evaluated potential agent due to long circulation and passive accumulation mechanisms at infection/inflammation site. Both radiopharmaceutical agents exhibit potential results in design, characterization, radiolabeling efficiency and in vitro bacterial binding point of view.

Research paper thumbnail of Scintigraphic imaging of infections with 99m-Tc-labelled glutathione liposomes

Journal of Microencapsulation, 2000

In this study, liposomes containing glutathione were evaluated to detect infection in mice. Gluta... more In this study, liposomes containing glutathione were evaluated to detect infection in mice. Glutathione liposomes were labelled by using 99mTclabelled-HMPAO (hexamethyl propylamine oxime). Mice were infected in the thigh by intramuscular injection with turbentine. Labelled liposomes were applied to the tail vein of the mice intravenously. At ® xed time intervals they were sacri® ced. The animals were imaged under a gamma camera. Then, tissue samples were excised and radioactivity of all organs was counted. Abscess-tomuscle, abscess-to-liver, and abscess-to-spleen ratios were calculated. The ratios of abscess-to-muscle were found to be 1.6 and 11.6 at 1 h and 24 h, respectively. According to these data, the abscess can be de® ned at 1 h and it became more clear with time.

Research paper thumbnail of Liposomes and micelles as nanocarriers for diagnostic and imaging purposes

Elsevier eBooks, 2018

Abstract Early diagnosis of a variety of diseases is very crucial for early therapy, therapy moni... more Abstract Early diagnosis of a variety of diseases is very crucial for early therapy, therapy monitoring, and therapy staging. Depending on the development in technology, a variety of imaging modalities initiated to enter routine use in hospital practice and research. The use of relatively newly developed imaging modalities and hybrid imaging systems requires the need of better, high contrast, localized radiocontrast/contrast imaging agents. Multifunctional nanocarriers are very promising systems for specific molecular imaging. Nano-sized liposomes and micelles are the reason of choice for researchers depending on their desirable properties, such as simple surface modification, biodegradability, biocompatibility, non-toxicity, ability to carry both hydrophilic and lipophilic substances due to amphiphilic structure, and targetability. They can also be used for both diagnosis and therapy of several diseases. The improvement in these specific imaging nanocarriers can help nuclear medicine and radiology physicians to diagnose and image disease sites earlier and more accurately.

Research paper thumbnail of Current and Future Approaches for Effective Cancer Imaging and Treatment

Cancer Biotherapy and Radiopharmaceuticals, Mar 1, 2018

Abstract Cancer poses a major health problem, not only due to cancer-related deaths but also beca... more Abstract Cancer poses a major health problem, not only due to cancer-related deaths but also because of treatment toxicities. This review discusses early diagnosis and strategies to overcome treatment difficulties, to facilitate recovery, and prevent deaths. Generally, noninvasive techniques such as computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT) and positron emission computed tomography (PET), and their hybrid systems, including SPECT/CT, PET/CT, and PET/MRI, are used in diagnosis of cancer. Cancer treatment in clinics still comprises conventional methods such as chemotherapy, radiotherapy, and surgery. However, these techniques and methods are often inadequate. Therefore, new approaches, including the formulation of actively and/or passively targeted nanosized drug delivery systems and combined treatment protocols, are being investigated. In this article, conventional cancer imaging and treatment are reviewed. In addition, the formulation of...

Research paper thumbnail of Nanosized drug delivery systems as radiopharmaceuticals

Elsevier eBooks, 2017

Abstract As widely known, radiopharmaceuticals are radionuclide comprising drugs. Radiopharmacy i... more Abstract As widely known, radiopharmaceuticals are radionuclide comprising drugs. Radiopharmacy is a speciality area of pharmacy dedicated to compounding, dispensing, and performing quality control and disposal of radiopharmaceuticals. Due to the development in electronic and computer engineering technology, new imaging modalities are going into routine usage in nuclear medicine practice for molecular imaging. The crucial point is the detection of molecular targets of diseases, which is different from normal tissues, such as an increase or decrease of the number/amount of a receptor, transporter, hormone, enzyme, or formation of a new target. Recently, development of radiolabeled, specific molecular targeted probes has been investigated for diagnosis of diseases more accurately by different imaging modalities. Nowadays, utilization of nanosized, specific targeted, different drug delivery systems, like liposomes, niosomes, sphingosomes, micelles, nanoparticles, nanobubbles, nanocapsules, gold nanoparticles, microspheres, microcapsules, microbubbles, dendrimers, polymeric systems, quantum dots, superparamagnetic particles is under consideration depending on convenient properties, such as biodegradability, biocompatibility, enhanced drug encapsulation and nontoxicity. Nanosized drug delivery systems can also be used for both diagnosis and therapy of several diseases as theranostics. In the future, the improvement in these nanosized, radiopharmaceuticals will lead to specific imaging and/or therapy of diseases at earlier stages essential for effective therapy.

Research paper thumbnail of 18th European Symposium on Radiopharmacy and Radiopharmaceuticals

EJNMMI Radiopharmacy and Chemistry, 2016

Background: The arginine-glycine-aspartic (RGD) peptide sequence serves as a high-affinity antago... more Background: The arginine-glycine-aspartic (RGD) peptide sequence serves as a high-affinity antagonist of the integrin α v β 3 receptor that plays an important role in tumor angiogenesis. Recently we reported [ 68 Ga]FSC(succ-RGD) 3 , a trimeric RGD peptide, exhibited excellent targeting properties for α v β 3 integrin expression and significant improved tumor uptake compared to monomeric [ 68 Ga]NODAGA-RGD.(1) Here we report the PET imaging properties of [ 68 Ga]FSC(succ-RGD) 3 in different xenograft tumor model and compared them with [ 68 Ga]NODAGA-RGD. Materials and methods: The PET imaging properties of [ 68 Ga]FSC(succ-RGD) 3 were studied in nude mice bearing M21 human melanoma xenografts and human glioblastoma U87MG xenograft tumor. A parallel PET imaging of 68 GaNODAGA-RGD in same mouse bearing U87MG xenograft tumor was performed as a comparison. Results: The static PET image of [ 68 Ga]FSC(succ-RGD) 3 in nude mice showed highly visualized tumors of M21 (positive) whereas nonvisualized tumor of M21-L (negative) tumor xenografts 1 h post injection confirming receptor-specific activity accumulation. The dynamic PET images of [ 68 Ga]FSC(succ-RGD) 3 showed rapid clearance of [ 68 Ga]FSC(succ-RGD) 3 from the circulation while the tumor remained clearly visible. A direct comparison of [ 68 Ga]FSC(succ-RGD) 3 with [ 68 Ga]NODAGA-RGD in nude mice bearing U87MG xenograft tumor using PET/CT resulted comparable target/background ratio (tumor/kidneys ratio = 1.3 and 1.6, tumor/ muscle ratio = 4.9, 5, respectively, 90 min post injection). The time activity curves from dynamic PET data showed an increase of the activity concentration of [ 68 Ga]FSC(succ-RGD) 3 in tumor firstly, then remained almost constant whereas that of [ 68 Ga]NO-DAGA-RGD decreased quickly. The significant enhanced tumor uptake (3.8 vs. 1.6 % ID/g) in addition to the slower washout rate from tumor for [ 68 Ga]FSC(succ-RGD) 3 not only allows the PET EJNMMI Radiopharmacy and Chemistry

Research paper thumbnail of Production and Quality Control of 201TlCl from SPECT Radiopharmaceuticals

Research paper thumbnail of Alternative Applications for Drug Delivery: Nasal and Pulmonary Routes

Springer eBooks, Sep 18, 2007

ABSTRACT For treatment of human diseases, nasal and pulmonary routes of drug delivery are gaining... more ABSTRACT For treatment of human diseases, nasal and pulmonary routes of drug delivery are gaining increasing importance. These routes provide promising alternatives to parenteral drug delivery particularly for peptide and protein therapeutics. For this purpose, several drug delivery systems have been formulated and are being investigated for nasal and pulmonary delivery. These include liposomes, proliposomes, microspheres, gels, prodrugs, cyclodextrins and others. In this chapter, nasal and pulmonary drug delivery mechanisms and some of the relevant drug delivery formulations are evaluated

Research paper thumbnail of The Effect of Radiation on a Variety of Pharmaceuticals and Materials Containing Polymers

Pda Journal of Pharmaceutical Science and Technology, Mar 1, 2012

Research paper thumbnail of Pharmacodynamic Comparison of a Nasal Formulation of Verapamil and Intravenous and Oral Dosage Forms

Drug Development and Industrial Pharmacy, 1996

ABSTRACT Abstract The nasal route has been shown to be effective for the administration of numero... more ABSTRACT Abstract The nasal route has been shown to be effective for the administration of numerous drugs in order to improve drug bioavailability. A nasal gel of verapamil hydrochloride was formulated and evaluated pharmacodynamically in humans, using electrocardiographic results, with comparison to oral and IV routes. Seven volunteers were involved in the study and the pharmacodynamic parameters were evaluated statistically. Experimental nasal gel showed similar pharmacodynamic results with the intravenous route, which is a hint to the reduction in verapamilinduced first-pass metabolism. However, oral route of administration showed a tendency of less efficacy. No reasonable effect of verapamil could be obtained with the placebo group.

Research paper thumbnail of Applications of Light and Electron Microscopic Techniques in Liposome Research

Springer eBooks, Sep 18, 2007

Liposomes and some other vesicular systems are widely used as delivery vehicles for bioactive com... more Liposomes and some other vesicular systems are widely used as delivery vehicles for bioactive compounds. Successful applications of these carrier systems in drug delivery, gene therapy and other health related areas depend on comprehensive understanding of their physical properties including polydispersity and morphology. Variations in size and shape of the carrier systems are indications of their stability and shelf life and can guide scientists in improving the therapeutic formulations. Towards this end microscopic techniques can provide vital information on size, configuration, stability and mechanisms of cellular uptake of particles on micro and nanoscales as discussed in this chapter

Research paper thumbnail of Advers Reactions to Radiopharmaceuticals: Kidney Imaging Radiopharmaceuticals

Research paper thumbnail of Copper-64 Radiopharmaceuticals: An Overview

Research paper thumbnail of Ticari Tc-99m-DTPA radyofarmasötik kitleri üzerine bir kalite kontrol çalışması

Research paper thumbnail of Clinical Applications of Nanosized Drug-Delivery Systems in Lung Cancer Imaging and Therapy

Critical Reviews in Therapeutic Drug Carrier Systems, 2020

Globally, lung cancer is one of the most frequently diagnosed and deadliest types of cancer. Lung... more Globally, lung cancer is one of the most frequently diagnosed and deadliest types of cancer. Lung cancer imaging can be performed using both invasive and noninvasive techniques, including magnetic resonance, positron emission tomography, single photon emission computed tomography, chest radiography, and computed tomography. But nonspecific contrast agents and radiopharmaceuticals are insufficient for early and specific diagnoses and imaging. In the case of lung cancer therapy, conventional therapeutic agents and radiotherapy may cause severe and systemic adverse and toxic effects and fail to eradicate all tumor tissue. Therefore, formulation of novel, targeted, and specific agents is critically important to overcome these challenges. In this review, we summarize lung cancer classification, current methods for lung cancer imaging and therapy, and future options containing nanosized systems for lung cancer imaging and/or therapy.

Research paper thumbnail of Radiolabeled, folate-conjugated liposomes as tumor imaging agents: Formulation and in vitro evaluation

Journal of Drug Delivery Science and Technology, Apr 1, 2019

Cancer is the major burden of disease worldwide. The folate receptor, as a specific tumor target,... more Cancer is the major burden of disease worldwide. The folate receptor, as a specific tumor target, is over-expressed in many types of cancer including ovarian carcinomas, breast, colon, renal, and lung tumors. Nuclear medicine hybrid imaging modalities, such as SPECT/CT, provide both metabolic and anatomic information. Therefore, specific contrast agents are essentially needed. Liposomes are favorable systems with many advantages. The aim of this study was to formulate liposomal imaging agents for molecular tumor imaging by SPECT or SPECT/CT and evaluate their efficacy. Nanosized, polyethyleneglycolated, folate-conjugated and unmodified, diethylenetriaminepentaacetic acid-phosphatidylethanolamine containing, neutral and positively charged liposomes were formulated and characterized by mean particle size, zeta potential, and quantitative determination of the phospholipids in the liposomes. The binding of the synthetized imaging agents to 4T1 breast tumor cells was evaluated by fluorescence microscopy and radioactivity counting. Folate-conjugated neutral and positively charged liposomes were found to be effective as tumor imaging agents exhibiting an almost 3-fold increased uptake and brighter fluorescence microscopy images than unmodified ones in in vitro experiments using 4T1 breast tumor cells. These results could be considered as an important step towards the development of folate-specific agents for tumor imaging by SPECT and SPECT/CT.

Research paper thumbnail of Targeted Alpha Therapy and Nanocarrier Approach

Cancer Biotherapy and Radiopharmaceuticals, Aug 1, 2020

The rates of cancer incidence and mortality are increasing day by day. Although several conventio... more The rates of cancer incidence and mortality are increasing day by day. Although several conventional methods including surgery, chemotherapy, and radiotherapy (RT) exist for cancer treatment, they are insufficient in the eradication of all tumor tissues and have some side-effects such as narrow therapeutic index and serious side-effects to healthy tissues. Moreover, it may probably recur in time due to the survival and spreading of cancerous cells or any possible metastases. Targeted radionuclide therapy is a promising alternative. α particles are ideal for localized cell killing because of their high linear energy transfer and short ranges. However, upon emission of α particles, the daughter nuclides induce a recoil energy to lead decoupling from any chemical bond that may accumulate in normal tissues. Targeted α therapy can also be performed by targeted delivery systems apart from mAb, mAb fragments, peptides, and small molecules for selective tumor therapy. Targeted drug delivery systems have been developed to overcome the limitations of α therapy. Moreover, drug delivery systems are one of the most searched applications in cancer imaging and/or treatment due to their targeting ability to tumor or biocompatibility properties. The aim of this article is to summarize tumor therapy applications, targeted α RT approach, and to review the role of drug delivery systems in the delivery of α particles for cancer therapy and some instances of targeted α-emitting drug delivery systems from the literature.

Research paper thumbnail of Drug Delivery Systems for Imaging and Therapy of Parkinson';s Disease

Current Neuropharmacology, Apr 8, 2016

Background: Although a variety of therapeutic approaches are available for the treatment of Parki... more Background: Although a variety of therapeutic approaches are available for the treatment of Parkinson's disease, challenges limit effective therapy. Among these challenges are delivery of drugs through the blood brain barier to the target brain tissue and the side effects observed during long term administration of antiparkinsonian drugs. The use of drug delivery systems such as liposomes, niosomes, micelles, nanoparticles, nanocapsules, gold nanoparticles, microspheres, microcapsules, nanobubbles, microbubbles and dendrimers is being investigated for diagnosis and therapy. Methods: This review focuses on formulation, development and advantages of nanosized drug delivery systems which can penetrate the central nervous system for the therapy and/or diagnosis of PD, and highlights future nanotechnological approaches. Results: It is esential to deliver a sufficient amount of either therapeutic or radiocontrast agents to the brain in order to provide the best possible efficacy or imaging without undesired degradation of the agent. Current treatments focus on motor symptoms, but these treatments generally do not deal with modifying the course of Parkinson's disease. Beyond pharmacological therapy, the identification of abnormal proteins such as α-synuclein, parkin or leucine-rich repeat serine/threonine protein kinase 2 could represent promising alternative targets for molecular imaging and therapy of Parkinson's disease. Conclusion: Nanotechnology and nanosized drug delivery systems are being investigated intensely and could have potential effect for Parkinson's disease. The improvement of drug delivery systems could dramatically enhance the effectiveness of Parkinson's Disease therapy and reduce its side effects.

Research paper thumbnail of Dtpa Niosomes in Diagnostic Imaging

Research paper thumbnail of Simultaneous Quantification of Paclitaxel and Vinorelbine Encapsulated in Theranostic Nanosized Liposomes

Journal of Analytical Chemistry, Jun 1, 2021

Cancer is one of the major health problems with an increasing incidence and mortality. Although i... more Cancer is one of the major health problems with an increasing incidence and mortality. Although imaging and effective treatment methods are critical issues to prevent cancer mortality, they are inadequate. Therefore, new approaches including combined treatment protocol and nanosized drug delivery theranostic systems are being investigated because of the deficiency of conventional cancer imaging and treatment methods in clinics. Liposomes attract attention in cancer imaging and treatment due to their advantages. In this study, an HPLC method was developed for simultaneous quantification of paclitaxel (PCX) and vinorelbine tartarate (VNB) in co-drug encapsulated theranostic nanosized liposome formulations as an effective cancer imaging and treatment agent. The method was validated according to ICH Analytical Method Validation guideline. According to the validation results, the method was found to be linear (r > 0.999), accurate (bias ≤ 1.8), precise (RSD ≤ 1.8%) and robust (p > 0.05). The developed method was successfully applied to the quantification of PCX and VBN in liposomes for encapsulation efficiency.

Research paper thumbnail of 99mTc-radiolabeled Levofloxacin and micelles as infection and inflammation imaging agents

Journal of Drug Delivery Science and Technology, Apr 1, 2020

Easy and early detection of infection and inflammation is essential for early and effective treat... more Easy and early detection of infection and inflammation is essential for early and effective treatment. In this study, PEGylated micelles were designed and both micelles and Levofloxacin were radiolabeled with 99m TcO 4 to develop potential radiotracers for detection of infection/inflammation. Radiolabeling efficiency, in vitro stability and bacterial binding of 99m Tc-Levofloxacin and 99m Tc-micelles were compared. The aim of this study is to formulate and compare 99m Tc-Levofloxacin and 99m Tc-micelles as infection and inflammation agents having different mechanisms for the accumulation at infection and inflammation site. PEGylated micelles were designed with a particle size of 80 ± 0.7 nm and proper characterization properties. High radiolabeling efficiency was achieved for 99m Tc-Levofloxacin (96%) and 99m Tc-micelles (87%). The radiolabeling efficiency was remained stable with some insignificant alterations for both radiotracers at 25°C for 24 h. Although in vitro bacterial binding of 99m Tc-levofloxacine was higher than 99m Tc-micelles, 99m Tc-micelles may also be evaluated potential agent due to long circulation and passive accumulation mechanisms at infection/inflammation site. Both radiopharmaceutical agents exhibit potential results in design, characterization, radiolabeling efficiency and in vitro bacterial binding point of view.

Research paper thumbnail of Scintigraphic imaging of infections with 99m-Tc-labelled glutathione liposomes

Journal of Microencapsulation, 2000

In this study, liposomes containing glutathione were evaluated to detect infection in mice. Gluta... more In this study, liposomes containing glutathione were evaluated to detect infection in mice. Glutathione liposomes were labelled by using 99mTclabelled-HMPAO (hexamethyl propylamine oxime). Mice were infected in the thigh by intramuscular injection with turbentine. Labelled liposomes were applied to the tail vein of the mice intravenously. At ® xed time intervals they were sacri® ced. The animals were imaged under a gamma camera. Then, tissue samples were excised and radioactivity of all organs was counted. Abscess-tomuscle, abscess-to-liver, and abscess-to-spleen ratios were calculated. The ratios of abscess-to-muscle were found to be 1.6 and 11.6 at 1 h and 24 h, respectively. According to these data, the abscess can be de® ned at 1 h and it became more clear with time.

Research paper thumbnail of Liposomes and micelles as nanocarriers for diagnostic and imaging purposes

Elsevier eBooks, 2018

Abstract Early diagnosis of a variety of diseases is very crucial for early therapy, therapy moni... more Abstract Early diagnosis of a variety of diseases is very crucial for early therapy, therapy monitoring, and therapy staging. Depending on the development in technology, a variety of imaging modalities initiated to enter routine use in hospital practice and research. The use of relatively newly developed imaging modalities and hybrid imaging systems requires the need of better, high contrast, localized radiocontrast/contrast imaging agents. Multifunctional nanocarriers are very promising systems for specific molecular imaging. Nano-sized liposomes and micelles are the reason of choice for researchers depending on their desirable properties, such as simple surface modification, biodegradability, biocompatibility, non-toxicity, ability to carry both hydrophilic and lipophilic substances due to amphiphilic structure, and targetability. They can also be used for both diagnosis and therapy of several diseases. The improvement in these specific imaging nanocarriers can help nuclear medicine and radiology physicians to diagnose and image disease sites earlier and more accurately.

Research paper thumbnail of Current and Future Approaches for Effective Cancer Imaging and Treatment

Cancer Biotherapy and Radiopharmaceuticals, Mar 1, 2018

Abstract Cancer poses a major health problem, not only due to cancer-related deaths but also beca... more Abstract Cancer poses a major health problem, not only due to cancer-related deaths but also because of treatment toxicities. This review discusses early diagnosis and strategies to overcome treatment difficulties, to facilitate recovery, and prevent deaths. Generally, noninvasive techniques such as computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT) and positron emission computed tomography (PET), and their hybrid systems, including SPECT/CT, PET/CT, and PET/MRI, are used in diagnosis of cancer. Cancer treatment in clinics still comprises conventional methods such as chemotherapy, radiotherapy, and surgery. However, these techniques and methods are often inadequate. Therefore, new approaches, including the formulation of actively and/or passively targeted nanosized drug delivery systems and combined treatment protocols, are being investigated. In this article, conventional cancer imaging and treatment are reviewed. In addition, the formulation of...

Research paper thumbnail of Nanosized drug delivery systems as radiopharmaceuticals

Elsevier eBooks, 2017

Abstract As widely known, radiopharmaceuticals are radionuclide comprising drugs. Radiopharmacy i... more Abstract As widely known, radiopharmaceuticals are radionuclide comprising drugs. Radiopharmacy is a speciality area of pharmacy dedicated to compounding, dispensing, and performing quality control and disposal of radiopharmaceuticals. Due to the development in electronic and computer engineering technology, new imaging modalities are going into routine usage in nuclear medicine practice for molecular imaging. The crucial point is the detection of molecular targets of diseases, which is different from normal tissues, such as an increase or decrease of the number/amount of a receptor, transporter, hormone, enzyme, or formation of a new target. Recently, development of radiolabeled, specific molecular targeted probes has been investigated for diagnosis of diseases more accurately by different imaging modalities. Nowadays, utilization of nanosized, specific targeted, different drug delivery systems, like liposomes, niosomes, sphingosomes, micelles, nanoparticles, nanobubbles, nanocapsules, gold nanoparticles, microspheres, microcapsules, microbubbles, dendrimers, polymeric systems, quantum dots, superparamagnetic particles is under consideration depending on convenient properties, such as biodegradability, biocompatibility, enhanced drug encapsulation and nontoxicity. Nanosized drug delivery systems can also be used for both diagnosis and therapy of several diseases as theranostics. In the future, the improvement in these nanosized, radiopharmaceuticals will lead to specific imaging and/or therapy of diseases at earlier stages essential for effective therapy.