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Stable High-Concentration Monoclonal Antibody Formulations Enabled by an Amphiphilic Copolymer Excipient. ADVANCED THERAPEUTICS 2023; 6:2200102. [PMID: 36684707 PMCID: PMC9854243 DOI: 10.1002/adtp.202200102] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Monoclonal antibodies are a staple in modern pharmacotherapy. Unfortunately, these biopharmaceuticals are limited by their tendency to aggregate in formulation, resulting in poor stability and often requiring low concentration drug formulations. Moreover, existing excipients designed to stabilize these formulations are often limited by their toxicity and tendency to form particles such as micelles. Here, we demonstrate the ability of a simple "drop-in", amphiphilic copolymer excipient to enhance the stability of high concentration formulations of clinically-relevant monoclonal antibodies without altering their pharmacokinetics or injectability. Through interfacial rheology and surface tension measurements, we demonstrate that the copolymer excipient competitively adsorbs to formulation interfaces. Further, through determination of monomeric composition and retained bioactivity through stressed aging, we show that this excipient confers a significant stability benefit to high concentration antibody formulations. Finally, we demonstrate that the excipient behaves as an inactive ingredient, having no significant impact on the pharmacokinetic profile of a clinically relevant antibody in mice. This amphiphilic copolymer excipient demonstrates promise as a simple formulation additive to create stable, high concentration antibody formulations, thereby enabling improved treatment options such as a route-of-administration switch from low concentration intravenous (IV) to high concentration subcutaneous (SC) delivery while reducing dependence on the cold chain.
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Injectable Nanoparticle-Based Hydrogels Enable the Safe and Effective Deployment of Immunostimulatory CD40 Agonist Antibodies. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2103677. [PMID: 35975424 PMCID: PMC9534946 DOI: 10.1002/advs.202103677] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 06/27/2022] [Indexed: 05/31/2023]
Abstract
When properly deployed, the immune system can eliminate deadly pathogens, eradicate metastatic cancers, and provide long-lasting protection from diverse diseases. Unfortunately, realizing these remarkable capabilities is inherently risky as disruption to immune homeostasis can elicit dangerous complications or autoimmune disorders. While current research is continuously expanding the arsenal of potent immunotherapeutics, there is a technological gap when it comes to controlling when, where, and how long these drugs act on the body. Here, this study explored the ability of a slow-releasing injectable hydrogel depot to reduce dose-limiting toxicities of immunostimulatory CD40 agonist (CD40a) while maintaining its potent anticancer efficacy. A previously described polymer-nanoparticle (PNP) hydrogel system is leveraged that exhibits shear-thinning and yield-stress properties that are hypothesized to improve locoregional delivery of CD40a immunotherapy. Using positron emission tomography, it is demonstrated that prolonged hydrogel-based delivery redistributes CD40a exposure to the tumor and the tumor draining lymph node (TdLN), thereby reducing weight loss, hepatotoxicity, and cytokine storm associated with standard treatment. Moreover, CD40a-loaded hydrogels mediate improved local cytokine induction in the TdLN and improve treatment efficacy in the B16F10 melanoma model. PNP hydrogels, therefore, represent a facile, drug-agnostic method to ameliorate immune-related adverse effects and explore locoregional delivery of immunostimulatory drugs.
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Formulation Excipients and Their Role in Insulin Stability and Association State in Formulation. Pharm Res 2022; 39:2721-2728. [PMID: 35978148 PMCID: PMC9633423 DOI: 10.1007/s11095-022-03367-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/10/2022] [Indexed: 10/15/2022]
Abstract
While excipients are often overlooked as the "inactive" ingredients in pharmaceutical formulations, they often play a critical role in protein stability and absorption kinetics. Recent work has identified an ultrafast absorbing insulin formulation that is the result of excipient modifications. Specifically, the insulin monomer can be isolated by replacing zinc and the phenolic preservative metacresol with phenoxyethanol as an antimicrobial agent and an amphiphilic acrylamide copolymer excipient for stability. A greater understanding is needed of the interplay between excipients, insulin association state, and stability in order to optimize this formulation. Here, we formulated insulin with different preservatives and stabilizing excipient concentrations using both insulin lispro and regular human insulin and assessed the insulin association states using analytical ultracentrifugation as well as formulation stability. We determined that phenoxyethanol is required to eliminate hexamers and promote a high monomer content even in a zinc-free lispro formulation. There is also a concentration dependent relationship between the concentration of polyacrylamide-based copolymer excipient and insulin stability, where a concentration greater than 0.1 g/mL copolymer is required for a mostly monomeric zinc-free lispro formulation to achieve stability exceeding that of Humalog in a stressed aging assay. Further, we determined that under the formulation conditions tested zinc-free regular human insulin remains primarily hexameric and is not at this time a promising candidate for rapid-acting formulations.
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Extreme Extensibility in Physically Cross-Linked Nanocomposite Hydrogels Leveraging Dynamic Polymer–Nanoparticle Interactions. Macromolecules 2022; 55:7498-7511. [PMID: 36118599 PMCID: PMC9476865 DOI: 10.1021/acs.macromol.2c00649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 08/02/2022] [Indexed: 11/28/2022]
Abstract
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Designing yield stress fluids to exhibit desired functional
properties
is an integral challenge in many applications such as 3D printing,
drilling, food formulation, fiber spinning, adhesives, and injectable
biomaterials. Extensibility in particular has been found to be a highly
beneficial characteristic for materials in these applications; however,
few highly extensible, high water content materials have been reported
to date. Herein we engineer a class of high water content nanocomposite
hydrogel materials leveraging multivalent, noncovalent, polymer–nanoparticle
(PNP) interactions between modified cellulose polymers and biodegradable
nanoparticles. We show that modulation of the chemical composition
of the PNP hydrogels controls the dynamic cross-linking interactions
within the polymer network and directly impacts yielding and viscoelastic
responses. These materials can be engineered to stretch up to 2000%
strain and occupy an unprecedented property regime for extensible
yield stress fluids. Moreover, a dimensional analysis of the relationships
between extensibility and the relaxation and recovery time scales
of these nanocomposite hydrogels uncovers generalizable design criteria
that will be critical for future development of extensible materials.
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Combinatorial Polyacrylamide Hydrogels for Preventing Biofouling on Implantable Biosensors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022. [PMID: 35390209 DOI: 10.1101/2020.05.25.115675] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Biofouling on the surface of implanted medical devices and biosensors severely hinders device functionality and drastically shortens device lifetime. Poly(ethylene glycol) and zwitterionic polymers are currently considered "gold-standard" device coatings to reduce biofouling. To discover novel anti-biofouling materials, a combinatorial library of polyacrylamide-based copolymer hydrogels is created, and their ability is screened to prevent fouling from serum and platelet-rich plasma in a high-throughput parallel assay. It is found that certain nonintuitive copolymer compositions exhibit superior anti-biofouling properties over current gold-standard materials, and machine learning is used to identify key molecular features underpinning their performance. For validation, the surfaces of electrochemical biosensors are coated with hydrogels and their anti-biofouling performance in vitro and in vivo in rodent models is evaluated. The copolymer hydrogels preserve device function and enable continuous measurements of a small-molecule drug in vivo better than gold-standard coatings. The novel methodology described enables the discovery of anti-biofouling materials that can extend the lifetime of real-time in vivo sensing devices.
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Combinatorial Polyacrylamide Hydrogels for Preventing Biofouling on Implantable Biosensors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109764. [PMID: 35390209 PMCID: PMC9793805 DOI: 10.1002/adma.202109764] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 04/04/2022] [Indexed: 05/29/2023]
Abstract
Biofouling on the surface of implanted medical devices and biosensors severely hinders device functionality and drastically shortens device lifetime. Poly(ethylene glycol) and zwitterionic polymers are currently considered "gold-standard" device coatings to reduce biofouling. To discover novel anti-biofouling materials, a combinatorial library of polyacrylamide-based copolymer hydrogels is created, and their ability is screened to prevent fouling from serum and platelet-rich plasma in a high-throughput parallel assay. It is found that certain nonintuitive copolymer compositions exhibit superior anti-biofouling properties over current gold-standard materials, and machine learning is used to identify key molecular features underpinning their performance. For validation, the surfaces of electrochemical biosensors are coated with hydrogels and their anti-biofouling performance in vitro and in vivo in rodent models is evaluated. The copolymer hydrogels preserve device function and enable continuous measurements of a small-molecule drug in vivo better than gold-standard coatings. The novel methodology described enables the discovery of anti-biofouling materials that can extend the lifetime of real-time in vivo sensing devices.
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Ultra-Fast Insulin-Pramlintide Co-Formulation for Improved Glucose Management in Diabetic Rats. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2101575. [PMID: 34499434 PMCID: PMC8564421 DOI: 10.1002/advs.202101575] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/07/2021] [Indexed: 05/04/2023]
Abstract
Dual-hormone replacement therapy with insulin and amylin in patients with type 1 diabetes has the potential to improve glucose management. Unfortunately, currently available formulations require burdensome separate injections at mealtimes and have disparate pharmacokinetics that do not mimic endogenous co-secretion. Here, amphiphilic acrylamide copolymers are used to create a stable co-formulation of monomeric insulin and amylin analogues (lispro and pramlintide) with synchronous pharmacokinetics and ultra-rapid action. The co-formulation is stable for over 16 h under stressed aging conditions, whereas commercial insulin lispro (Humalog) aggregates in 8 h. The faster pharmacokinetics of monomeric insulin in this co-formulation result in increased insulin-pramlintide overlap of 75 ± 6% compared to only 47 ± 7% for separate injections. The co-formulation results in similar delay in gastric emptying compared to pramlintide delivered separately. In a glucose challenge, in rats, the co-formulation reduces deviation from baseline glucose compared to insulin only, or separate insulin and pramlintide administrations. Further, comparison of interspecies pharmacokinetics of monomeric pramlintide suggests that pharmacokinetics observed for the co-formulation will be well preserved in future translation to humans. Together these results suggest that the co-formulation has the potential to improve mealtime glucose management and reduce patient burden in the treatment of diabetes.
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Abstract
There are 150 million people with diabetes worldwide who require insulin replacement therapy, and the prevalence of diabetes is rising the fastest in middle- and low-income countries. The current formulations require costly refrigerated transport and storage to prevent loss of insulin integrity. This study shows the development of simple "drop-in" amphiphilic copolymer excipients to maintain formulation integrity, bioactivity, pharmacokinetics, and pharmacodynamics for over 6 months when subjected to severe stressed aging conditions that cause current commercial formulation to fail in under 2 weeks. Further, when these copolymers are added to Humulin R (Eli Lilly) in original commercial packaging, they prevent insulin aggregation for up to 4 days at 50 °C compared to less than 1 day for Humulin R alone. These copolymers demonstrate promise as simple formulation additives to increase the cold chain resilience of commercial insulin formulations, thereby expanding global access to these critical drugs for treatment of diabetes.
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Affinity-Directed Dynamics of Host-Guest Motifs for Pharmacokinetic Modulation via Supramolecular PEGylation. Biomacromolecules 2021; 22:3565-3573. [PMID: 34314146 PMCID: PMC8627827 DOI: 10.1021/acs.biomac.1c00648] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Proteins are an impactful class of therapeutics but can exhibit suboptimal therapeutic performance, arising from poor control over the timescale of clearance. Covalent PEGylation is one established strategy to extend circulation time but often at the cost of reduced activity and increased immunogenicity. Supramolecular PEGylation may afford similar benefits without necessitating that the protein be permanently modified with a polymer. Here, we show that insulin pharmacokinetics can be modulated by tuning the affinity-directed dynamics of a host-guest motif used to non-covalently endow insulin with a poly(ethylene glycol) (PEG) chain. When administered subcutaneously, supramolecular PEGylation with higher binding affinities extends the time of total insulin exposure systemically. Pharmacokinetic modeling reveals that the extension in the duration of exposure arises specifically from decreased absorption from the subcutaneous depot governed directly by the affinity and dynamics of host-guest exchange. The lifetime of the supramolecular interaction thus dictates the rate of absorption, with negligible impact attributed to association of the PEG upon rapid dilution of the supramolecular complex in circulation. This modular approach to supramolecular PEGylation offers a powerful tool to tune protein pharmacokinetics in response to the needs of different disease applications.
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An ultrafast insulin formulation enabled by high-throughput screening of engineered polymeric excipients. Sci Transl Med 2021; 12:12/550/eaba6676. [PMID: 32611683 DOI: 10.1126/scitranslmed.aba6676] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 05/20/2020] [Indexed: 12/13/2022]
Abstract
Insulin has been used to treat diabetes for almost 100 years; yet, current rapid-acting insulin formulations do not have sufficiently fast pharmacokinetics to maintain tight glycemic control at mealtimes. Dissociation of the insulin hexamer, the primary association state of insulin in rapid-acting formulations, is the rate-limiting step that leads to delayed onset and extended duration of action. A formulation of insulin monomers would more closely mimic endogenous postprandial insulin secretion, but monomeric insulin is unstable in solution using present formulation strategies and rapidly aggregates into amyloid fibrils. Here, we implement high-throughput-controlled radical polymerization techniques to generate a large library of acrylamide carrier/dopant copolymer (AC/DC) excipients designed to reduce insulin aggregation. Our top-performing AC/DC excipient candidate enabled the development of an ultrafast-absorbing insulin lispro (UFAL) formulation, which remains stable under stressed aging conditions for 25 ± 1 hours compared to 5 ± 2 hours for commercial fast-acting insulin lispro formulations (Humalog). In a porcine model of insulin-deficient diabetes, UFAL exhibited peak action at 9 ± 4 min, whereas commercial Humalog exhibited peak action at 25 ± 10 min. These ultrafast kinetics make UFAL a promising candidate for improving glucose control and reducing burden for patients with diabetes.
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Full closed loop open-source algorithm performance comparison in pigs with diabetes. Clin Transl Med 2021; 11:e387. [PMID: 33931977 PMCID: PMC8087942 DOI: 10.1002/ctm2.387] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/24/2021] [Accepted: 03/30/2021] [Indexed: 12/20/2022] Open
Abstract
Understanding how automated insulin delivery (AID) algorithm features impact glucose control under full closed loop delivery represents a critical step toward reducing patient burden by eliminating the need for carbohydrate entries at mealtimes. Here, we use a pig model of diabetes to compare AndroidAPS and Loop open‐source AID systems without meal announcements. Overall time‐in‐range (70–180 mg/dl) for AndroidAPS was 58% ± 5%, while time‐in‐range for Loop was 35% ± 5%. The effect of the algorithms on time‐in‐range differed between meals and overnight. During the overnight monitoring period, pigs had an average time‐in‐range of 90% ± 7% when on AndroidAPS compared to 22% ± 8% on Loop. Time‐in‐hypoglycemia also differed significantly during the lunch meal, whereby pigs running AndroidAPS spent an average of 1.4% (+0.4/−0.8)% in hypoglycemia compared to 10% (+3/−6)% for those using Loop. As algorithm design for closed loop systems continues to develop, the strategies employed in the OpenAPS algorithm (known as oref1) as implemented in AndroidAPS for unannounced meals may result in a better overall control for full closed loop systems.
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Enhanced Humoral Immune Response by High Density TLR Agonist Presentation on Hyperbranched Polymers. ADVANCED THERAPEUTICS 2021. [DOI: 10.1002/adtp.202000081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Self-Assembled, Dilution-Responsive Hydrogels for Enhanced Thermal Stability of Insulin Biopharmaceuticals. ACS Biomater Sci Eng 2020; 7:4221-4229. [PMID: 34510910 PMCID: PMC8441967 DOI: 10.1021/acsbiomaterials.0c01306] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
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Biotherapeutics currently dominate
the landscape of new drugs because
of their exceptional potency and selectivity. Yet, the intricate molecular
structures that give rise to these beneficial qualities also render
them unstable in formulation. Hydrogels have shown potential as stabilizing
excipients for biotherapeutic drugs, providing protection against
harsh thermal conditions experienced during distribution and storage.
In this work, we report the utilization of a cellulose-based supramolecular
hydrogel formed from polymer–nanoparticle (PNP) interactions
to encapsulate and stabilize insulin, an important biotherapeutic
used widely to treat diabetes. Encapsulation of insulin in these hydrogels
prevents insulin aggregation and maintains insulin bioactivity through
stressed aging conditions of elevated temperature and continuous agitation
for over 28 days. Further, insulin can be easily recovered by dilution
of these hydrogels for administration at the point of care. This supramolecular
hydrogel system shows promise as a stabilizing excipient to reduce
the cold chain dependence of insulin and other biotherapeutics.
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A co-formulation of supramolecularly stabilized insulin and pramlintide enhances mealtime glucagon suppression in diabetic pigs. Nat Biomed Eng 2020; 4:507-517. [PMID: 32393892 PMCID: PMC7274092 DOI: 10.1038/s41551-020-0555-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 04/03/2020] [Indexed: 02/06/2023]
Abstract
Treatment of patients with diabetes with insulin and pramlintide (an amylin analogue) is more effective than treatment with insulin only. However, because mixtures of insulin and pramlintide are unstable and have to be injected separately, amylin analogues are only used by 1.5% of people with diabetes needing rapid-acting insulin. Here, we show that the supramolecular modification of insulin and pramlintide with cucurbit[7]uril-conjugated polyethylene glycol improves the pharmacokinetics of the dual-hormone therapy and enhances postprandial glucagon suppression in diabetic pigs. The co-formulation is stable for over 100 h at 37 °C under continuous agitation, whereas commercial formulations of insulin analogues aggregate after 10 h under similar conditions. In diabetic rats, the administration of the stabilized co-formulation increased the area-of-overlap ratio of the pharmacokinetic curves of pramlintide and insulin from 0.4 ± 0.2 to 0.7 ± 0.1 (mean ± s.d.) for the separate administration of the hormones. The co-administration of supramolecularly stabilized insulin and pramlintide better mimics the endogenous kinetics of co-secreted insulin and amylin, and holds promise as a dual-hormone replacement therapy.
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Stable Monomeric Insulin Formulations Enabled by Supramolecular PEGylation of Insulin Analogues. ADVANCED THERAPEUTICS 2020; 3:1900094. [PMID: 32190729 PMCID: PMC7079736 DOI: 10.1002/adtp.201900094] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Indexed: 12/17/2022]
Abstract
Current "fast-acting" insulin analogues contain amino acid modifications meant to inhibit dimer formation and shift the equilibrium of association states toward the monomeric state. However, the insulin monomer is highly unstable and current formulation techniques require insulin to primarily exist as hexamers to prevent aggregation into inactive and immunogenic amyloids. Insulin formulation excipients have thus been traditionally selected to promote insulin association into the hexameric form to enhance formulation stability. This study exploits a novel excipient for the supramolecular PEGylation of insulin analogues, including aspart and lispro, to enhance the stability and maximize the prevalence of insulin monomers in formulation. Using multiple techniques, it is demonstrated that judicious choice of formulation excipients (tonicity agents and parenteral preservatives) enables insulin analogue formulations with 70-80% monomer and supramolecular PEGylation imbued stability under stressed aging for over 100 h without altering the insulin association state. Comparatively, commercial "fast-acting" formulations contain less than 1% monomer and remain stable for only 10 h under the same stressed aging conditions. This simple and effective formulation approach shows promise for next-generation ultrafast insulin formulations with a short duration of action that can reduce the risk of post-prandial hypoglycemia in the treatment of diabetes.
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Block copolymer composition drives function of self-assembled nanoparticles for delivery of small-molecule cargo. JOURNAL OF POLYMER SCIENCE. PART A, POLYMER CHEMISTRY 2019; 57:1322-1332. [PMID: 31244507 PMCID: PMC6582505 DOI: 10.1002/pola.29393] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 04/16/2019] [Indexed: 12/20/2022]
Abstract
Nanoparticles are useful for the delivery of small molecule therapeutics, increasing their solubility, in vivo residence time, and stability. Here, we used organocatalytic ring opening polymerization to produce amphiphilic block copolymers for the formation of nanoparticle drug carriers with enhanced stability, cargo encapsulation, and sustained delivery. These polymers comprised blocks of poly(ethylene glycol) (PEG), poly(valerolactone) (PVL), and poly(lactide) (PLA). Four particle chemistries were examined: (a) PEG-PLA, (b) PEG-PVL, (c) a physical mixture of PEG-PLA and PEG-PVL, and (d) PEG-PVL-PLA tri-block copolymers. Nanoparticle stability was assessed at room temperature (20 °C; pH = 7), physiological temperature (37 °C; pH = 7), in acidic media (37 °C; pH = 2), and with a digestive enzyme (lipase; 37 °C; pH = 7.4). PVL-based nanoparticles demonstrated the highest level of stability at room temperature, 37 °C and acidic conditions, but were rapidly degraded by lipase. Moreover, PVL-based nanoparticles demonstrated good cargo encapsulation, but rapid release. In contrast, PLA-based nanoparticles demonstrated poor stability and encapsulation, but sustained release. The PEG-PVL-PLA nanoparticles exhibited the best combination of stability, encapsulation, and release properties. Our results demonstrate the ability to tune nanoparticle properties by modifying the polymeric architecture and composition. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1322-1332.
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Abstract
Polymeric chains crosslinked through supramolecular interactions-directional and reversible non-covalent interactions-compose an emerging class of modular and tunable biomaterials. The choice of chemical moiety utilized in the crosslink affords different thermodynamic and kinetic parameters of association, which in turn illustrate the connectivity and dynamics of the system. These parameters, coupled with the choice of polymeric architecture, can then be engineered to control environmental responsiveness, viscoelasticity, and cargo diffusion profiles, yielding advanced biomaterials which demonstrate rapid shear-thinning, self-healing, and extended release. In this review we examine the relationship between supramolecular crosslink chemistry and biomedically relevant macroscopic properties. We then describe how these properties are currently leveraged in the development of materials for drug delivery, immunology, regenerative medicine, and 3D-bioprinting (253 references).
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An alternative method for the certification of the sulfur mass fraction in coal Standard Reference Materials. FRESENIUS' JOURNAL OF ANALYTICAL CHEMISTRY 2001; 370:234-40. [PMID: 11451243 DOI: 10.1007/s002160100821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The S mass fractions of coal SRMs 2682b, 2684b, and 2685b are certified by direct comparison with coal SRMs 2682a, 2684a, and 2685a, respectively, using high-temperature combustion analysis with infrared (IR) absorption detection. The S mass fractions of the "a" materials used for calibration were previously determined by means of isotope-dilution thermal-ionization mass spectrometry (ID-TIMS). Therefore, the comparisons performed with the combustion-IR absorption method establish direct traceability links to accurate and precise ID-TIMS measurements. The expanded uncertainties associated with the certified S mass fractions are of approximately the same magnitude as would be expected for the ID-TIMS methodology. An important aspect of these certifications is that each "b" material is essentially identical with the corresponding "a" material, because both were produced from the same bulk, homogenized coal. As a test of the efficacy of the new certification approach when calibrant and unknown are not identical, the S mass fraction of coal SRM 2683b has been determined by direct comparison to coal SRM 2683a. These two coals, which have both previously been analyzed with ID-TIMS, are different in terms of S content and other properties. Whereas the S mass fraction for SRM 2683b determined with the new methodology agrees statistically with the ID-TIMS value, there is reason for caution in such cases. In addition to the usefulness of the alternative approach for certification activities within NIST, this approach might also be an excellent way of establishing NIST traceability during the value assignment process for reference materials not issued by NIST. Further research is needed, however, to understand better the scope of applicability.
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Abstract
OBJECTIVE To evaluate endoglin, a membrane protein and member of the transforming growth factor beta-1 receptor complex, as an endothelial marker of angiogenesis in cervical cancer tissues. METHODS Tumor tissue was collected from 31 surgically treated stage IB nonbulky (under 5 cm) cervical cancer subjects, and samples were fixed in formalin and embedded in paraffin. Endoglin was stained on 5-microm slide sections by the DAKO Catalyzed Signal Amplification method (DAKO Corporation, Carpinteria, CA). Factor VIII was stained by standard immunohistochemistry. Positively stained microvessels were counted in "hot spots" at 200x magnification. Clinical data were correlated with vessel counts by Spearman correlation. Mean differences in counts were tested using paired t tests. RESULTS This staining method for endoglin identified significantly more vessels than the factor VIII method (mean 92 +/- 45 versus 33 +/- 16, P <. 001). Endoglin and factor VIII counts correlated significantly with deep stromal invasion (Spearman rho 0.466 and 0.522, respectively, P <.05); however, only endoglin counts correlated significantly with lymph node metastases (rho =.495, P <.01). CONCLUSION Endoglin is stimulated in tumor angiogenesis and might be relatively more specific than commonly used endothelial markers. The endoglin system was more sensitive for staining capillaries in neoplastic cervical tissue, better predicted lymph node metastases, and should be widely applicable for the study of other tumors.
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Panhypopituitarism. PEDIATRIC NURSING 1999; 25:654-5, 669. [PMID: 12024385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
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Drug utilization & therapeutic intervention programs: pharmacy services that pay for themselves. Can J Hosp Pharm 1994; 47:203-8. [PMID: 10137698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
This mailed survey was a follow-up to a 1989 study to assess the status of pharmacy-directed, drug-related, patient care programs in response to the Pharmaceutical Inquiry of Ontario (Lowy Inquiry). A specific focus on Therapeutic Interventions and Drug Utilization Review/Evaluation Programs was adopted because the earlier study indicated a significant "financial return" for pharmacist time spent on these initiatives. A response rate of 62.2% (89 out of 143 hospitals) was achieved compared with an 80% response rate in 1989. Therapeutic interventions were performed by 97.7% of hospitals which identified an average of 184 therapeutic interventions per month and an 84.3% acceptance rate by prescriber. Based on data from 53 hospitals, an average of 29 minutes was taken on each intervention and financial data from 10 hospitals showed cost savings/avoidance of $49.34 per intervention. Drug Utilization program data was available from 45% of hospitals and specific financial data was provided by 29.2% of institutions. Cost savings/avoidance data demonstrated a return of $29.99 for every dollar invested in pharmacist time performing these activities. Collectively, both programs were recognized for their value in optimizing pharmacotherapy, improving patient outcomes as well as demonstrating a financial return to the institution. Despite the recessionary times, these programs are easily justified since they more than pay their own way.
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Abstract
A 76-year-old woman was referred after results of the biopsy of an ulcerated mass of the right long finger suggested poorly differentiated squamous cell carcinoma. Excision and skin grafting were done and a diagnosis of malignant acrospiroma was established. These tumors are aggressive and 5-year survival rate may be as low as 30%. A ray amputation was subsequently done and the specimen was without residual tumor. At 14 months follow-up, the patient remains free of disease.
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Survey of pharmacotherapy monitoring in Canadian acute care hospitals. Can J Hosp Pharm 1989; 42:229-34. [PMID: 10296655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
A survey questionnaire was sent to all hospitals in Canada that had 100 or more acute care beds. Objectives were to determine the current level and extent of pharmacist monitoring and prescriber acceptance of recommendations with respect to patient drug therapy. Three levels of patient drug therapy monitoring were identified, as were two extended forms of service. The response rate was 52.0 percent (130/250). A majority (92.3 percent) of respondents monitor drug therapy from the pharmacy, and only 6.2 percent provide monitoring service on patient wards. Among the respondents, 75.4 percent reviewed all (more than 90 percent) medication orders before the drug was dispensed for the patients. Of the respondents, 32.3 percent provided pharmacokinetic monitoring and 29.9 percent provided proactive pharmacist interventions via rounding with physicians. Higher levels of monitoring were associated with higher levels of pharmacy staffing. The acceptance rate of pharmacist recommendations by prescribers was more than 80 percent.
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24
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Serum drug level utilization: a literature analysis. Can J Hosp Pharm 1989; 42:63-8, 88. [PMID: 10318233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
A literature analysis was performed to quantify and evaluate the amount of inappropriate utilization of serum drug level assays. Studies that determined appropriate use based on institution-specific criteria were extracted from the literature. Inappropriate use was categorized as to indication, sampling, or use of results. Canadian studies were isolated and compared to American studies. A total of 35 studies was identified as meeting the study criteria. The rates of inappropriate utilization of drug level assays were 34.7% for indication, 47.2% for sampling, and 40.2% for use of results. Twelve studies reported an overall average inappropriate use of 58.8%. Estimations of annual waste due to inappropriate blood level use ranged from $1,221 to $100,917 per hospital. Canadian studies reported rates of 37.2%, 52.5%, and 44.5% for the three categories, respectively, and an overall inappropriate rate of 53.3%. None of these values differed significantly from those of American studies (p greater than .1). It was concluded that there is a great deal of inappropriate drug level utilization that wastes much in terms of patient care, personnel time, and costs. A great potential exists for pharmacists to intervene and improve this area of drug utilization.
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25
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Fibrous dysplasia masquerading as chronic maxillary sinusitis. EAR, NOSE & THROAT JOURNAL 1989; 68:42, 44-6. [PMID: 2656231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Fibrous dysplasia is a rare disease of unknown cause that affects one or multiple bones. In its monostotic form, only one bone is involved. The maxilla is the most commonly affected facial bone. Facial deformity with or without pain is the most common presentation of fibrous dysplasia affecting the craniofacial bones. In certain cases the disorder can present clinically as chronic maxillary sinusitis. The clinical, radiologic, and histologic findings, as well as the differential diagnosis and treatment of this condition are reviewed.
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Direction through accreditation--CCHA (Canadian Council on Hospital Accreditation) recommendations to Ontario hospital pharmacies. Can J Hosp Pharm 1988; 41:303-7. [PMID: 10291355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
A questionnaire was circulated in December 1986 to 157 Ontario hospital pharmacy directors that asked about the recent recommendations made by CCHA surveyors. Sixty-four directors responded and assigned their received recommendations to four categories of pharmacy service. Similar recommendations were tabulated by category of service and by number of hospital beds (less than 200 and greater than 200 beds). The results show that drug distribution was the most emphasized area of service cited for improvement. Frequent recommendations concerned patient medication profiles, night supply services, hospital formulary, Pharmacy and Therapeutics Committee policy review, adverse drug reaction programs, quality assurance, and regular medication room checks. Responses indicated that 27 of the 62 eligible hospital pharmacies (44%) that received recommendations have acquired administrative support to implement changes, and 33 of 62 (53%) have had specific action as a result of an accreditation survey.
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Abstract
Results of detailed staging laparotomy for Hodgkin's disease with supradiaphragmatic presentation in 78 patients showed 28 with subdiaphragmatic involvement. All 28 patients with intra-abdominal disease had splenic involvement. On the basis of findings of this study and published series on staging laparotomy, it is proposed that the spleen is the first site of intra-abdominal disease in this group of patients, and that Hodgkin's disease spreads to the intra-abdominal lymph nodes, liver, and bone marrow from the spleen.
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28
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Pharmacy innovation: a public and private partnership. Can J Hosp Pharm 1986; 39:107-8. [PMID: 10278470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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29
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Issues in pharmacy management: time for action. DIMENSIONS IN HEALTH SERVICE 1985; 62:10-1, 16. [PMID: 4076587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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30
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Drug distribution: a philosophy. Can J Hosp Pharm 1985; 37:59-61, 67. [PMID: 10266861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Hospital pharmacy has made significant progress in the last two decades by any of a number of program evaluation methods. However equally apparent are our current deficiencies in the level of service provided in our drug distribution systems in Canadian hospitals. It is apparent that we will not be allowed to abrogate our responsibility any longer in that it is becoming recognized in medical, nursing and administrative circles that compounding and dispensing functions are clearly in the realm of a pharmacist's responsibility and these issues must be addressed if we can truly claim to be part of a world class health care system. Hospital pharmacists must take the initiative in accepting responsibility for chemotherapy preparations, I.V. additives and compounding as well as the adoption of a unit dose drug distribution system as a positive means to reduce medication errors. The report of the Hospital for Sick Children Review Committee makes it equally clear that society has expectations of an institutional pharmacy service that are considerably beyond that which we are accustomed to providing. The recommendations relating to pharmacy provide adequate support to facilitate the establishment of a contemporary drug distribution system in Canadian hospitals. Similarly the C.S.H.P. Standards of Pharmacy Practice and the Canadian Council on Hospital Accreditation Guidelines for Pharmacy Service offer additional "ammunition" for us individually and collectively to change the face of hospital pharmacy practice. The profession must take stock of its responsibilities before society insists that someone else take over where pharmacists have failed.
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31
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Unit dose: it's feasible and reasonable. HEALTH CARE 1984; 26:30-1, 33. [PMID: 10265246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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32
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Abstract
Many pathogenic fungi have been found to autofluoresce in routine hematoxylin and eosin sections when exposed to ultraviolet light. These fungi include Blastomyces, Cryptococcus, Candida, Aspergillus, Coccidioides, and occasionally, Histoplasma. No autofluorescence was observed with Mucor. Examinations of other inflammatory processes, including those producing a granulomatous response, have not revealed any false-positive results. The advantages of fluorescent microscopy for fungal screening include: (1) no special staining procedures required; (2) no time delay, as involved with special stains; (3) the ability to scan sections at a relatively low power; and (4) the ability to tentatively identify the fungus. Disadvantages may include: (1) lack of a fluorescent microscope, and (2) a possible aging process whereby autofluorescence is lost in older cases.
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Clinical pharmacy services: Part II--the issues. Can J Hosp Pharm 1981; 34:173-7, 191. [PMID: 10253750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
The development of clinical pharmacy programs over the past decade has been both dramatic and satisfying as well as divisive and frustrating. In our experience the broad spectrum of possible clinical activities is responsible for both situations as it concerns the individual pharmacist. At Sunnybrook, liaison pharmacists have accepted departmentally prioritized clinical activities as their primary focus while removed from the distribution system. Documentation for each individual staff member, satellite and departmental achievements for patient counselling, adverse reaction and drug information programs was undertaken to provide visible endpoints for both staff and administration. Hospital Pharmacy visibility to the lay public, a need expressed by several prominent practitioners, has been addressed by the production of a Pharmacy Services Brochure which helps to educate in-patients about our many programs. Lastly the attempt by several colleagues to evaluate the profession's clinical impact by means of a quality assurance program illustrates the difficult task ahead of us if we are to indeed demonstrate an improved patient care program through our efforts.
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Clinical pharmacy activities: a quantitative assessment at Sunnybrook Medical Centre. Can J Hosp Pharm 1981; 34:139-43. [PMID: 10253748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Levels of clinical pharmacy activity were assessed at Sunnybrook Medical Centre using levine et al's concept of Patient Care Units. Data from pharmacist-initiated log sheets (for two four-week periods) were collated and described under the headings of: "Average Clinical Time Per Day", "Number of Specific Clinical Encounters Per Month", "Average Percentage of Total Clinical Time Per Encounter", and "Average Time Per Specific Clinical Encounter". It was noted that only 21.7 to 26.0% of working time was spent on clinical interactions and that many of these activities did not involve patients. For example, clinical non-distributive interactions with professionals (other than physicians or nurses) and attendance at pharmacy educational functions, accounted for the largest portion of clinical time. Most of the patient encounters that did occur consisted of the indirect activity of chart review, instead of the more direct-discharge interviews, allergy verifications, and medication histories, it was apparent from the log sheet results that there was an individual prioritization of clinical activities by the Sunnybrook pharmacists. However, a departmental assumption that direct patient encounters had priority was not evident.
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Pharmacy-nursing Kardex rounds--a communication technique. DRUG INTELLIGENCE & CLINICAL PHARMACY 1981; 15:216. [PMID: 7274040 DOI: 10.1177/106002808101500315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Drug information--the pharmacist's contribution. HOSPITAL ADMINISTRATION IN CANADA 1977; 19:40-1, 44. [PMID: 10241963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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