Our knowledge of a drug’s potential for harm is incomplete at the time of drug licensing leaving residual questions about the long-term safety and effectiveness of drugs in the ‘real world’. Pharmacoepidemiologic research can contribute to the study of the unintended effects of drugs. The central aims of this dissertation were to create new knowledge about drug-related harm in the postmarketing environment using pharmacoepidemiologic methods and larged linked databases, and understand how various types of design and analytic strategies can be applied to reduce bias and threats to internal validity when studying drug harm. The aims of the thesis were achieved by performing three studies. The first study examined elderly individuals hospitalized with bradycardia and identified an association with recent initiation of cholinesterase inhibitor therapy (adjusted odds-ratio 2.13, 95% confidence interval 1.29 to 3.51). The second study examined the measurement properties of administrative diagnostic codes for subtrochanteric and femoral shaft fractures and found the positive predictive value and sensitivity of the codes to be reasonably good (90% and 81%, respectively). This study was linked to the third study which explored the association between long-term bisphosphonate use and subtrochanteric or femoral shaft fractures in postmenopausal women and found an increased risk of these unusual fractures in women with greater than 5 years of bisphosphonate use. The research performed as part of this thesis provides an example of the types of new knowledge about drug-related harm that can be generated using pharmacoepidemiologic designs and analytic strategies. The pharmacoepidemiologic studies will play an important and dynamic role in the larger evolving focus on post-marketing drug safety and effectiveness as new data sources become increasingly available and and the methods within the pharmacoepidemiologic discipline become more sophisticated and refined.

Our knowledge of a drug’s potential for harm is incomplete at the time of drug licensing leaving residual questions about the long-term safety and effectiveness of drugs in the ‘real world’. Pharmacoepidemiologic research can contribute to the study of the unintended effects of drugs. The central aims of this dissertation were to create new knowledge about drug-related harm in the postmarketing environment using pharmacoepidemiologic methods and larged linked databases, and understand how various types of design and analytic strategies can be applied to reduce bias and threats to internal validity when studying drug harm. The aims of the thesis were achieved by performing three studies. The first study examined elderly individuals hospitalized with bradycardia and identified an association with recent initiation of cholinesterase inhibitor therapy (adjusted odds-ratio 2.13, 95% confidence interval 1.29 to 3.51). The second study examined the measurement properties of administrative diagnostic codes for subtrochanteric and femoral shaft fractures and found the positive predictive value and sensitivity of the codes to be reasonably good (90% and 81%, respectively). This study was linked to the third study which explored the association between long-term bisphosphonate use and subtrochanteric or femoral shaft fractures in postmenopausal women and found an increased risk of these unusual fractures in women with greater than 5 years of bisphosphonate use. The research performed as part of this thesis provides an example of the types of new knowledge about drug-related harm that can be generated using pharmacoepidemiologic designs and analytic strategies. The pharmacoepidemiologic studies will play an important and dynamic role in the larger evolving focus on post-marketing drug safety and effectiveness as new data sources become increasingly available and and the methods within the pharmacoepidemiologic discipline become more sophisticated and refined.

The main objective of this research was to better understand, predict and control of the periodic precipitation process and to apply such programmed periodic precipitation to the design of a pulsatile delivery system. In the first part of this study, a generalized model taking into account both nucleation, particle growth, and ripening process was refined and solved under various new concentration boundary conditions not previously investigated. The results clearly delineate the key differences between boundary conditions of infinite versus finite supply of inner electrolyte. When the inner electrolyte boundary concentration was allowed to increase exponentially with time, equidistant periodic precipitation was predicted and subsequently confirmed experimentally. In addition, the effects of product solubility and reaction rate constant were also shown to be important in determining the band number and band spacing. In the second part of this study, the effects of gel crosslinking and gel charge density on the periodic precipitation were investigated. The results indicate that by increasing either the gel crosslinking or decreasing the gel charge density will reduce the diffusion rate of the reactants resulting in closely spaced bands. In addition, a new and improved rotating disk method for characterizing polyelectrolyte gels with ion-penetrable soft surfaces has been established by taking into account the effect of surface conductivity which is usually ignored for ion-impenetrable hard surfaces. In the third part of this work, periodic precipitation formed in multi-component systems has been shown to be governed by a heterogeneous nucleation mechanism. Using this approach, periodic precipitation of an insulin mimetic compound VO2+ in gelatin gel, which cannot form alone in a single reaction system, was induced by the periodic precipitation of Mg(OH)2 in a multi-component system. Pulsatile release of VO2+ from the resulting multi-layered structure of VO(OH)2 via a surface erosion mechanism was subsequently demonstrated.

The main objective of this research was to better understand, predict and control of the periodic precipitation process and to apply such programmed periodic precipitation to the design of a pulsatile delivery system. In the first part of this study, a generalized model taking into account both nucleation, particle growth, and ripening process was refined and solved under various new concentration boundary conditions not previously investigated. The results clearly delineate the key differences between boundary conditions of infinite versus finite supply of inner electrolyte. When the inner electrolyte boundary concentration was allowed to increase exponentially with time, equidistant periodic precipitation was predicted and subsequently confirmed experimentally. In addition, the effects of product solubility and reaction rate constant were also shown to be important in determining the band number and band spacing. In the second part of this study, the effects of gel crosslinking and gel charge density on the periodic precipitation were investigated. The results indicate that by increasing either the gel crosslinking or decreasing the gel charge density will reduce the diffusion rate of the reactants resulting in closely spaced bands. In addition, a new and improved rotating disk method for characterizing polyelectrolyte gels with ion-penetrable soft surfaces has been established by taking into account the effect of surface conductivity which is usually ignored for ion-impenetrable hard surfaces. In the third part of this work, periodic precipitation formed in multi-component systems has been shown to be governed by a heterogeneous nucleation mechanism. Using this approach, periodic precipitation of an insulin mimetic compound VO2+ in gelatin gel, which cannot form alone in a single reaction system, was induced by the periodic precipitation of Mg(OH)2 in a multi-component system. Pulsatile release of VO2+ from the resulting multi-layered structure of VO(OH)2 via a surface erosion mechanism was subsequently demonstrated.

Background: Unmitigated immunization pain in infants has the potential to impact long-term health outcomes. Teaching parents in the prenatal period may increase utilization of pain management (PM) strategies in clinical practice. Objective: To assess the efficaciousness of teaching parents in the prenatal environment and its impact on the number of analgesic PM strategies utilized during the 2-month immunization appointment. Methods: This partially blinded cluster randomized controlled trial enrolled mothers from prenatal classes at Mount Sinai Hospital. Classes were randomized to receive a presentation on either immunization PM or general immunization information. Results: One hundred and ninety-seven mothers from 28 classes participated in this study. There was a statistically significant increase (p<0.01) in the use of one or more analgesic interventions in the group that received a presentation on immunization PM compared to those who received general immunization information. Conclusions: Prenatal classes are a suitable environment to educate parents about immunization PM.

Background: Unmitigated immunization pain in infants has the potential to impact long-term health outcomes. Teaching parents in the prenatal period may increase utilization of pain management (PM) strategies in clinical practice. Objective: To assess the efficaciousness of teaching parents in the prenatal environment and its impact on the number of analgesic PM strategies utilized during the 2-month immunization appointment. Methods: This partially blinded cluster randomized controlled trial enrolled mothers from prenatal classes at Mount Sinai Hospital. Classes were randomized to receive a presentation on either immunization PM or general immunization information. Results: One hundred and ninety-seven mothers from 28 classes participated in this study. There was a statistically significant increase (p<0.01) in the use of one or more analgesic interventions in the group that received a presentation on immunization PM compared to those who received general immunization information. Conclusions: Prenatal classes are a suitable environment to educate parents about immunization PM.

Nevirapine (NVP) can cause serious idiosyncratic drug reactions (IDRs); specifically, skin rash and hepatotoxicity. Treatment of rats or mice with NVP led to covalent binding to hepatic proteins. Studies of this covalent binding including the use of a deuterated analog of NVP leading to a decrease in oxidation of the methyl group indicated that the metabolite responsible for covalent binding in the liver is a quinone methide. Covalent binding in NVP-treated rats was also observed in the epidermis but by a different pathway. Incubation of 12-OH-NVP sulfate with homogenized human and rat skin led to extensive covalent binding. Inhibition of sulfation in the liver significantly decreased 12-OH-NVP sulfate in the blood, but it did not prevent covalent binding in the skin or the rash. In contrast, topical application of a sulfotransferase inhibitor prevented covalent binding in the skin as well as the rash, but only where it was applied. In contrast to rats, treatment of mice with NVP did not result in covalent binding in the skin or skin rash. These findings provide compelling evidence that 12-OH-NVP sulfate formed in the skin is responsible for the skin rash. IL-1β and IL-18 production in the skin of rats treated with NVP were increased. An anti-IL-1ß antibody significantly decreased rash severity. These cytokines were also produced by incubation of human keratinocytes with 12-OH-NVP sulfate. These data indicate that 12-OH-NVP sulfate activates the NLRP3 inflammasome, a pathway known to be responsible for contact hypersensitivity rashes. In summary, NVP was found to produce two different reactive metabolites, a quinone methide species in the liver, and a benzylic sulfate in the skin. Significant liver injury did not occur, presumably due to immune tolerance. Although it is usually assumed that reactive metabolites are responsible for most IDRs, this is the first example to actually demonstrate that a specific reactive metabolite is responsible for an IDR. This is also the first study to show that sulfotransferase in the skin is responsible for bioactivation of a drug leading to a skin rash. It is likely that there are other drugs that cause skin rashes by a similar mechanism.

Nevirapine (NVP) can cause serious idiosyncratic drug reactions (IDRs); specifically, skin rash and hepatotoxicity. Treatment of rats or mice with NVP led to covalent binding to hepatic proteins. Studies of this covalent binding including the use of a deuterated analog of NVP leading to a decrease in oxidation of the methyl group indicated that the metabolite responsible for covalent binding in the liver is a quinone methide. Covalent binding in NVP-treated rats was also observed in the epidermis but by a different pathway. Incubation of 12-OH-NVP sulfate with homogenized human and rat skin led to extensive covalent binding. Inhibition of sulfation in the liver significantly decreased 12-OH-NVP sulfate in the blood, but it did not prevent covalent binding in the skin or the rash. In contrast, topical application of a sulfotransferase inhibitor prevented covalent binding in the skin as well as the rash, but only where it was applied. In contrast to rats, treatment of mice with NVP did not result in covalent binding in the skin or skin rash. These findings provide compelling evidence that 12-OH-NVP sulfate formed in the skin is responsible for the skin rash. IL-1β and IL-18 production in the skin of rats treated with NVP were increased. An anti-IL-1ß antibody significantly decreased rash severity. These cytokines were also produced by incubation of human keratinocytes with 12-OH-NVP sulfate. These data indicate that 12-OH-NVP sulfate activates the NLRP3 inflammasome, a pathway known to be responsible for contact hypersensitivity rashes. In summary, NVP was found to produce two different reactive metabolites, a quinone methide species in the liver, and a benzylic sulfate in the skin. Significant liver injury did not occur, presumably due to immune tolerance. Although it is usually assumed that reactive metabolites are responsible for most IDRs, this is the first example to actually demonstrate that a specific reactive metabolite is responsible for an IDR. This is also the first study to show that sulfotransferase in the skin is responsible for bioactivation of a drug leading to a skin rash. It is likely that there are other drugs that cause skin rashes by a similar mechanism.

Mitochondria play essential roles in numerous cellular processes, including oxidative phosphorylation and apoptotic initiation. As a result, organellar dysfunction has been implicated in several pathologies such as cancer, diabetes and neurodegenerative diseases. The opportunity to deliver compounds to probe or treat these conditions would be highly beneficial but accessing this organelle is challenging. Prior work investigated the physicochemical properties required for mitochondrial targeting and yielded mitochondria-penetrating peptides (MPPs). MPPs possess hydrophobic and cationic character and exhibit efficient cellular uptake and mitochondrial localization. In this proof-of-principle study, MPPs were harnessed to re-route an anti-leukemia agent, chlorambucil (Cbl), from the nucleus to mitochondria. This DNA alkylating agent was selected for its rapid kinetics and facile conjugation to an MPP. In addition, because mitochondria possess their own genome, the target of this drug would also be present in the organelle. Conjugation of an MPP to Cbl (mt-Cbl) confirmed that the drug was re-routed to the mitochondria and an increase in potency was observed in several cell lines and patient samples. This gain in activity was due to the increased accessibility of the mitochondrial genome, its lack of introns and its limited repair capacity. However, despite this enhanced toxicity, a therapeutic window continued to be maintained due to the elevated mitochondrial membrane potential in cancer cells. The re-routing of Cbl also resulted in evasion of several drug resistance mechanisms. Damage directly within the organelle was sufficient to initiate apoptosis even in cell lines with disabled apoptotic triggering. In addition, mitochondrial sequestration protected mt-Cbl from drug inactivation mechanisms. Lastly, mt-Cbl inhibited Pgp efflux by unexpectedly interacting with the pumps and inhibiting activity for a short period of time. The anti-cancer activity of mt-Cbl was also assessed in vivo in xenograft models of leukemia. The conjugate was stable in mouse plasma and displayed an improved pharmacokinetic profile. In addition, mt-Cbl successfully delayed tumor growth in two xenograft models and continued to alkylate mitochondrial DNA in vivo. These studies demonstrate that MPPs can be harnessed to re-route drugs to this organelle. Mitochondrial re-targeting could be a novel method of re-purposing FDA-approved drugs to enhance activity and evade resistance.

The use of multimodal imaging as a tool to assess the in vivo pharmacokinetics and biodistribution of nanoparticles is important in drug development and imaging-guided therapy. The current study reports the use of combined micro-CT and optical imaging FMT to quantitatively assess the whole body and intratumoural distribution of a nano-sized liposome-based CT/optical imaging probe carrying iohexol and Cy5.5. Micro-CT was used to guide the FMT tumour delineation and signal correction. This investigation demonstrates the critical role micro-CT can play in guiding FMT-based quantification of distribution. As well the combination of CT and optical imaging enable visualization of the liposomes at the whole body, tumor and cellular levels with high sensitivity and excellent anatomical background. Such non-invasive assessment of therapeutic distribution at the macro and micro scale is necessary for implementation of personalized medicine including image-guided patient stratification and real-time adjustment of therapeutic dose.