The Development of a Novel Aflibercept Formulation for Ocular Delivery

Aflibercept is a recombinant fusion protein that is commercially available for several ocular diseases impacting millions of people worldwide. Here, we use a case study approach to examine alternative liquid formulations for aflibercept for ocular delivery, utilizing different stabilizers, buffering agents, and surfactants with the goal of improving the thermostability to allow for limited storage outside the cold chain. The formulations were developed by studying the effects of pH changes, substituting amino acids for sucrose and salt, and using polysorbate 80 or poloxamer 188 instead of polysorbate 20. A formulation containing acetate, proline, and poloxamer 188 had lower rates of aggregate formation at 4, 30, and 40°C when compared to the marketed commercial formulation containing phosphate, sucrose, sodium chloride, and polysorbate 20. Further studies examining subvisible particles after exposure to a transport stress and long-term stability at 4°C, post-translational modifications by multi-attribute method, purity by reduced and non-reduced capillary electrophoresis, and potency by cell proliferation also demonstrated a comparable or improved stability for the enhanced formulation of acetate, proline, and poloxamer 188. This enhanced stability could enable limited storage outside of the cold chain, allowing for easier distribution in low to middle income countries.

Evaluation of Crystal Zenith Microtiter Plates for High-Throughput Formulation Screening

Formulation screening for biotherapeutics can cover a vast array of excipients and stress conditions. These studies consume quantities of limited material and, with higher concentrated therapeutics, more material is needed. Here, we evaluate the use of crystal zenith (CZ) microtiter plates in conjunction with FluoroTec-coated butyl rubber mats as a small-volume, high-throughput system for formulation stability studies. The system was studied for evaporation, edge effects, and stability with comparisons to type 1 glass and CZ vials for multiple antibodies and formulations. Evaporation was minimal at 4°C and could be reduced at elevated temperatures using sealed, mylar bags. Edge effects were not observed until 12 weeks at 40°C. The overall stability ranking as measured by the rate of change in high molecular weight and percent main peak species was comparable across both vials and plates at 4°C and 40°C out to 12 weeks. Product quality attributes as measured by the multi-attribute method were also comparable across all containers for each molecule formulation. A potential difference was measured for subvisible particle analysis, with the plates measuring lower particle counts than the vials. Overall, CZ plates are a viable alternative to traditional vials for small-volume, high-throughput formulation stability screening studies.

Adapting the chemical unfolding assay for high-throughput protein screening using experimental and spectroscopic corrections

The chemical unfolding (denaturation) assay can be used to calculate the change in the Gibbs free energy of unfolding, ΔG, and inflection point of unfolding, to collectively inform on molecule stability. Here, we evaluated methods for calculating the ΔG across 23 monoclonal antibody sequence variants. These methods are based on how the measured output (intrinsic fluorescence intensity) is treated, including utilizing (a) a single wavelength, (b) a ratio of two wavelengths, (c) a ratio of a single wavelength to an area, and (d) a scatter correction plus a ratio of a single wavelength to an area. When applied to the variants, the three ratio methods showed comparable results, with a similar pooled standard deviation for the ΔG calculation, while the single-wavelength method is shown as inadequate for the data in this study. However, when light scattering is introduced to simulated data, only the scatter-correction area normalization method proves robust. Using this method, common plate-based spectrophotometers found in many laboratories can be used for high-throughput screening of mAb variants and formulation stability studies.

Drug encapsulated aerosolized microspheres as a biodegradable, intelligent glioma therapy

The grim prognosis for patients diagnosed with malignant gliomas necessitates the development of new therapeutic strategies for localized and sustained drug delivery to combat tumor drug resistance and regrowth. Here we introduce drug encapsulated aerosolized microspheres as a biodegradable, intelligent glioma therapy (DREAM BIG therapy). DREAM BIG therapy is envisioned to deliver three chemotherapeutics, temporally staged over one year, via a bioadhesive, biodegradable spray directly to the brain surgical site after tumor excision. In this proof-of-principle article exploring key components of the DREAM BIG therapy prototype, rhodamine B (RB) encapsulated poly(lactic-co-glycolic acid) and immunoglobulin G (IgG) encapsulated poly(lactic acid) microspheres were formulated and characterized. The encapsulation efficiency of RB and IgG and the release kinetics of the model drugs from the microspheres were elucidated in addition to the release kinetics of RB from poly(lactic-co-glycolic acid) microspheres formulated in a degradable poly(N-isopropylacrylamide) solution. The successful aerosolized application onto brain tissue ex-vivo demonstrated the conformal adhesion of the RB encapsulated poly(lactic-co-glycolic acid) microspheres to the convoluted brain surface mediated by the thermoresponsive carrier, poly(N-isopropylacrylamide). These preliminary results suggest the potential of the DREAM BIG therapy for future use with multiple chemotherapeutics and microsphere types to combat gliomas at a localized site.

Human reserve pluripotent mesenchymal stem cells are present in the connective tissues of skeletal muscle and dermis derived from fetal, adult, and geriatric donors

This study details the profile of 13 cell surface cluster differentiation markers on human reserve stem cells derived from connective tissues. Stem cells were isolated from the connective tissues of dermis and skeletal muscle derived from fetal, mature, and geriatric humans. An insulin/dexamethasone phenotypic bioassay was used to determine the identity of the stem cells from each population. All populations contained lineage-committed myogenic, adipogenic, chondrogenic, and osteogenic progenitor stem cells as well as lineage-uncommitted pluripotent stem cells capable of forming muscle, adipocytes, cartilage, bone, fibroblasts, and endothelial cells. Flow cytometric analysis of adult stem cell populations revealed positive staining for CD34 and CD90 and negative staining for CD3, CD4, CD8, CD11c, CD33, CD36, CD38, CD45, CD117, Glycophorin-A, and HLA DR-II.

Clonogenic analysis reveals reserve stem cells in postnatal mammals: I. Pluripotent mesenchymal stem cells

Clonal populations of lineage-uncommitted pluripotent mesenchymal stem cells have been identified in prenatal avians and rodents. These cells reside in the connective tissue matrices of many organs and tissues. They demonstrate extended capabilities for self-renewal and the ability to differentiate into multiple separate tissues within the mesodermal germ line. This study was designed to determine whether such cells are present in the connective tissues of postnatal mammals. This report describes a cell clone derived by isolation from postnatal rat connective tissues, cryopreservation, extended propagation, and serial dilution clonogenic analysis. In the undifferentiated state, this clone demonstrates a high nuclear-to-cytoplasmic ratio and extended capacity for self-renewal. Subsequent morphological, histochemical, and immunochemical analysis after the induction of differentiation revealed phenotypic markers characteristic of multiple cell types of mesodermal origin, such as skeletal muscle, smooth muscle, fat cells, cartilage, and bone. These results indicate that this clone consists of pluripotent mesenchymal stem cells. This report demonstrates that clonal populations of reserve stem cells are present in mammals after birth. Potential roles for such cells in the maintenance, repair, and regeneration of mesodermal tissues are discussed.

Nonlinear components of age-related change in sleep initiation

BACKGROUND

Although primary studies suggest that ability to initiate sleep declines as people age, no systematic literature review has addressed the age(s) at which adults experience the greatest change in their ability to initiate sleep.

OBJECTIVE

To explore whether there are any points in time across the adult life span when the rate of change in ability to initiate sleep increases or decreases.

METHODS

Mathematical modeling was used to generate data points from information about central tendency, variance, and correlations between age and time to sleep onset provided by seven research reports. The reports represent 258 subjects ages 17 to 91 years. Smoothing splines were used to identify inflection points suggestive of major changes in sleep initiation across the life span.

RESULTS

Two mathematical models were generated. One model suggested that inflection points may exist around ages 30 and 50 years, respectively. With this model, the amount of time until sleep onset increased until the age of 30 years, but was unchanged from ages 30 to 50 years. Ability to initiate sleep appeared to decline steadily after the age of 50 years. The second model, with a p value of 0.05, lacked adequate power to identify a significant nonlinear trend.

CONCLUSIONS

Decline in ability to initiate sleep may not occur at a steady rate over the adult life span. Further research is needed to pinpoint thresholds of change and possible gender differences in thresholds.

Creation and analysis of a computerized database of interventions to facilitate adult sleep

BACKGROUND

Although sleep problems are a frequent complaint of ill and older adults, there is no ready source of continually updated scientific knowledge about sleep promotion interventions used by nurses.

OBJECTIVES

To create a database of sleep promotion research and to describe the nature and strength of studies about nursing interventions used to promote sleep in adults.

METHODS

Computer, hand, ancestry, and author searches were used to identify nursing and related-discipline studies of sleep promotion in adults. An experimental software program, arcs, was used to store, retrieve, examine, and summarize sleep research findings.

RESULTS

Twelve interventions within the basic scope of nursing practice were identified. All were nonpharmacologic. Interventions were grouped according to their presumed mechanism of action: 1) to relax the sleeper, 2) to manage noise, 3) to re-pattern the sleep-wake schedule, or 4) to inform the sleeper about sleep hygiene.

CONCLUSIONS

The research base underpinning sleep promotion practices in nursing is sparse. The use of relaxation approaches to promote sleep in those with chronic insomnia has the most support. Extensive research involving other interventions and populations is needed. As more studies become available, they can be added to the computer database, thus facilitating dissemination of scientific knowledge to guide nursing practice.

Age-related changes in initiation and maintenance of sleep: a meta-analysis

The purpose of this meta-analysis was to determine the magnitude of change over the adult life span in four key sleep characteristics and to explore research design features that may account for variability in reported age-related sleep change. Forty-one published studies (combined N = 3293) provided 99 correlational effect sizes. Waking frequency and duration increased with age as previously concluded by narrative reviewers. Although narrative reviewers were less certain whether nighttime sleep amount or the ability to initiate sleep decreased with age, the meta-analysis suggested that both decreased. When sleep variables were measured by polysomnography rather than self-report, larger age-related changes were found. Few researchers who studied normal sleep controlled for important health moderators or studied women.

The use of the arcs software system to store and examine sleep research results

Ready access to research results is essential if nurses are to keep current with the scientific knowledge available to guide practice. Sigma Theta Tau International has supported the development of a software system that facilitates ongoing storage of information from research reports and can be used to gain online access to continually updated databases of research results called "knowledgebases." One such experimental knowledgebase, the Sleep Promotion Knowledgebase, includes studies of correlates of poor sleep in adults as well as sleep interventions and outcomes. The authors describe the creation of the Sleep Promotion Knowledgebase using arcs BUILDER to store information about research reports and the scientific findings they contain. The use of arcs MAPPER to examine sleep promotion interventions also is described. The strengths and limitations of the software system are identified, and the potential uses of arcs to disseminate sleep research results are discussed.

Sleep promotion in adults

Insomnia is among the most frequent health complaints brought to the attention of primary care providers. The prevalence estimates are highest in women, older adults, and patients with medical or psychiatric disorders. Clinical researchers have studied many barriers to sleep as well as some sleep promotion interventions for the ill and aging adult. Environmental, personal, and person-environment rhythm factors have been identified as correlates of poor sleep. All interventions studied by nurse researchers are non-pharmacological and have been classified as interventions that (a) create an environment more conductive to sleep, (b) relax the sleeper, or (c) entrain the circadian sleep-wake rhythm. This chapter summarizes results of published research on correlates of poor sleep and interventions to promote sleep. The chapter includes the relevant studies conducted by researchers in related disciplines as well as nurses' research. The arcs software package was used to facilitate summarization of intervention studies. It was concluded that correlates of poor sleep are well described, but theories of sleep promotion are not well explicated. Also, the research base for sleep promotion interventions for use with clinical populations other than those with chronic insomnia is sparse. Gaps in knowledge are identified and conceptual and methodological issues are discussed as the basis for future directions in sleep promotion research.

The use of across-method triangulation in the study of sleep concerns in healthy older adults

Both qualitative and quantitative methods were used to study sleep concerns of 84 healthy adults ages 60 to 89. The combined use of methods in one study brought sampling, data-collection, and data-interpretation issues to the forefront. This article describes a sampling method that accommodates assumptions of both paradigms, reports results of an experimental approach to examining the effects of each method on the other, and identifies convergent and disparate findings regarding sleep concerns of older adults. Self-report measures affected qualitative interviews but not vice versa. Also, age-by-method and gender-by-method interactions were evident.

Nursing students' stress levels, attitude toward drugs, and drug use

This study investigated relationships among nursing students' drug use and two variables usually assumed to contribute to the development of chemical dependency in nurses, i.e., stress and positive attitudes about drugs. Drug use was defined as the use of any psychoactive substance including prescription drugs, over-the-counter drugs, recreational drugs, nicotine, and alcohol. Questionnaires, were distributed to senior-year nursing students and a comparison group of seniors in liberal arts. The only significant difference in reported drug use was nursing students' more frequent use of over-the-counter analgesics. There were no significant differences between nursing and liberal arts majors with regard to three symptoms of stress. Nursing students reported more positive attitudes toward the use of some drugs than peers.

Interaction between personal sleep-wake rhythms and psychiatric hospital rest-activity schedule

A sample of 35 psychiatric inpatients were matched on gender and psychiatric diagnosis with 35 psychiatric outpatients. Both groups were given the Self-Assessment Questionnaire to Determine Morningness-Eveningness (Horne & Ostberg, 1976), and asked to record their sleep-wake patterns on a modified form of the Lewis and Masterton Sleep Chart (1957). The purpose was to explore the interactions between individual circadian rhythms of sleep and wakefulness and the hospital's rest-activity schedule. As hypothesized, inpatients slept less than outpatients (p = less than .05), but the mean total sleep time of evening types was not different from morning types. Circadian type was a good predictor of times of falling asleep and awakening for outpatients but not for inpatients, whose schedules appeared to be phase shifted by the hospital's rest-activity schedule. It was concluded that the theory of interacting rhythms guiding the study requires reformulation and that further research regarding the positive or negative effects of phase shifting is needed.