Structural heterogeneities in starch hydrogels

Hydrogels have a complex, heterogeneous structure and organisation, making them promising candidates for advanced structural and cosmetics applications. Starch is an attractive material for producing hydrogels due to its low cost and biocompatibility, but the structural dynamics of polymer chains within starch hydrogels are not well understood, limiting their development and utilisation. We employed a range of NMR methodologies (CPSP/MAS, HR-MAS, HPDEC and WPT-CP) to probe the molecular mobility and water dynamics within starch hydrogels featuring a wide range of physical properties. The insights from these methods were related to bulk rheological, thermal (DSC) and crystalline (PXRD) properties. We have reported for the first time the presence of highly dynamic starch chains, behaving as solvated moieties existing in the liquid component of hydrogel systems. We have correlated the chains’ degree of structural mobility with macroscopic properties of the bulk systems, providing new insights into the structure-function relationships governing hydrogel assemblies

Novel Polysaccharide Based Polymers and Nanoparticles for Controlled Drug Delivery and Biomedical Imaging

The use of polysaccharides as building blocks in the development of drugs and contrast agents delivery systems is rapidly growing. This can be attributed to the outstanding virtues of polysaccharides such as biocompatibility, biodegradability, upgradability, multiple reacting groups and low cost. The focus of this thesis was to develop and characterize novel starch based hydrogels and nanoparticles for delivery of drugs and imaging agents. To this end, two different systems were developed. The first system includes polymer and nanoparticles prepared by graft polymerization of polymethacrylic acid and polysorbate 80 onto starch. This starch based platform nanotechnology was developed using the design principles based on the pathophysiology of breast cancer, with applications in both medical imaging and breast cancer chemotherapy. The nanoparticles exhibited a high degree of doxorubicin loading as well as sustained pH dependent release of the drug. The drug loaded nanoparticles were significantly more effective against multidrug resistant human breast cancer cells compared to free doxorubicin. Systemic administration of the starch based nanoparticles co-loaded with doxorubicin and a near infrared fluorescent probe allowed for non-invasive real time monitoring of the nanoparticles biodistribution, tumor accumulation, and clearance. Systemic administration of the clinically relevant doses of the drug loaded particles to a mouse model of breast cancer significantly enhanced therapeutic efficacy while minimizing side effects compared to free doxorubicin. A novel, starch based magnetic resonance imaging (MRI) contrast agent with good in vitro and in vivo tolerability was formulated which exhibited superior signal enhancement in tumor and vasculature. The second system is a co-polymeric hydrogel of starch and xanthan gum with adjustable swelling and permeation properties. The hydrogels exhibited excellent film forming capability, and appeared to be particularly useful in controlled delivery applications of larger molecular size compounds. The starch based hydrogels, polymers and nanoparticles developed in this work have shown great potentials for controlled drug delivery and biomedical imaging applications.Ph

Leg amputation following intramuscular injection of iron dextran in a 32 year old woman

To inform healthcare professionals of a rare serious reaction leading to leg amputation following intramuscular injection of iron dextran and report comments for preventing such reactions.A case of leg amputation following intramuscular injection of iron dextran reported to Iranian Pharmacovigilance Center was reviewed. Patient and reaction data was collected by assessing the reported yellow card, patient chart review and interviewing with patient and physicians. World Health Organization definition for serious reactions was used to determine the seriousness of the reaction. Naranjo algorithm was used to determine probability scale. The probability of the reaction was determined based on questionnaire of Schumock et al. The studied case is classified as a rare and serious but preventable reaction induced by intramuscular injection of iron dextran in a 32 year old woman. The probability of the reaction is appeared to be “probable” based on Naranjo algorithm. It seems that Iron dextran could cause serious and life threatening adverse effects. It is necessary for healthcare professionals to be informed of such rare but serious reaction in order to apply preventive actions

Evaluation of anti-tuberculosis induced adverse reactions in hospitalized patients

Background: Tuberculosis has been one of the common diseases of human communities. Besides of disease-related complications, there are serious adverse reactions due to Anti-tuberculosis (Anti-TB) drug therapy. Objectives: To assess the rate of Adverse Drug Reactions (ADRs) induced by Anti-TB drugs in the infectious disease department for a period of one year. To detect serious and preventable recognized ADRs. Methods: All patients admitted to the infectious disease department at Imam tertiary teaching hospital in Iran who received Anti-TB drugs from July 2001 to July 2002 entered the study. These patients were monitored for ADRs during hospital stay. The ADRs were then classified based on patients and reactions factors. The causality and severity of the reactions were determined using Naranjo algorithm and Hartwig questionnaire, respectively. Results: During the study period, 83 patients received Anti-TB drugs; of them 44 developed at least one ADR. Total number of 81 ADRs was detected in this study. ADRs were recognized as the major cause of hospital admission in 11 (13.3%) patients. The most frequent system-organ class affected by ADRs was Liver and biliary system (37%). Hepatitis was observed in 21 (25.3%) patients leading to death in two patients. Conclusion: Anti-TB drugs could cause significant adverse effects both in quantity and severity leading to hospitalization, prolonged hospital stay and even death. More attention is needed to prevent these reactions

Evaluation of anti-tuberculosis induced adverse reactions in hospitalized patients

Background: Tuberculosis has been one of the common diseases of human communities. Besides of disease-related complications, there are serious adverse reactions due to Anti-tuberculosis (Anti-TB) drug therapy. Objectives: To assess the rate of Adverse Drug Reactions (ADRs) induced by Anti-TB drugs in the infectious disease department for a period of one year. To detect serious and preventable recognized ADRs. Methods: All patients admitted to the infectious disease department at Imam tertiary teaching hospital in Iran who received Anti-TB drugs from July 2001 to July 2002 entered the study. These patients were monitored for ADRs during hospital stay. The ADRs were then classified based on patients and reactions factors. The causality and severity of the reactions were determined using Naranjo algorithm and Hartwig questionnaire, respectively. Results: During the study period, 83 patients received Anti-TB drugs; of them 44 developed at least one ADR. Total number of 81 ADRs was detected in this study. ADRs were recognized as the major cause of hospital admission in 11 (13.3%) patients. The most frequent system-organ class affected by ADRs was Liver and biliary system (37%). Hepatitis was observed in 21 (25.3%) patients leading to death in two patients. Conclusion: Anti-TB drugs could cause significant adverse effects both in quantity and severity leading to hospitalization, prolonged hospital stay and even death. More attention is needed to prevent these reactions

Adverse reactions of anti-tuberculosis drugs in hospitalized patients: incidence, severity and risk factors

Tuberculosis (TB) has been a common chronic infectious disease in human communities. Besides disease-related complications, there could be serious adverse reactions due to anti-tuberculosis (anti-TB) drug therapy. To assess the incidence and severity of adverse drug reactions (ADRs) induced by anti-TB drugs. To determine possible covariates associated with detected ADRs. All patients with respiratory TB admitted to a teaching hospital who received anti-TB drugs during the research period entered the study and were monitored for ADRs. Socio-demographic and medical history of patients were used as independent covariates. The relationship between independent covariates with frequency and severity of ADRs was analysed using multivariate logistic regression. Preliminary analyses of the Mann-Whitney, Chi-square, Kruskal-Wallis and the Fisher's exact tests were applied to determine factors unlikely associated with the independent variables. Among 204 patients admitted, there were 92 patients (45.1%) with ADRs induced by anti-TB drugs. Patients with a previous history of anti-TB drugs usage (OR = 5.81, 95% confidence interval [95%CI]: 1.31-25.2), patients with a history of drug allergy (OR = 6.68, CI: 1.28-36.2), those from Afghani ethnic (OR = 4.91, 95%CI: 1.28-18.30) as well as smoker patients with concurrent diseases (OR = 19.67, CI: 1.24-341.51) had a higher rate of ADR incidence. Being female (OR = 1.63, 95%CI: 1.96-36.40) and having previous history of ADR (OR = 17.46, 95%CI: 1.96-20.42) were identified as risk factors. Anti-TB drugs could cause severe and frequent adverse effects. Females, those with a previous history of ADRs to anti-TB drugs and Afghani patients, should be considered as high-risk groups