Student Performance with Standalone Calculations Course vs Combined Pharmaceutics-Calculations Course

Objective. To determine whether a standalone pharmacy calculations course promotes student performance and retention when compared to pharmacy calculations taught within a pharmaceutics course. Methods. Data were compared between two groups of student pharmacists (those who took the combined pharmaceutics-calculations course and those who took the standalone calculations course). Data from both groups, such as course grades, objective structured clinical evaluation (OSCE) scores, and independent calculation self-assessment skills test scores were compared to students' pre-pharmacy math grade point average (GPA) to determine whether variance was more likely to have been caused by inter-student aptitude differences or course structure differences. Student confidence in their pharmacy calculations skills and course structure preferences was surveyed. Results. Students who took the standalone pharmaceutical calculations course performed better as indicated by an improvement in calculations course grades, OSCE performance, retention of calculation skills, and in self-confidence. Students also reported that the standalone course structure was more effective. Conclusion. The new, standalone calculations course is effective and improved student calculations performance and retention.

Exosomes as therapeutic drug carriers and delivery vehicles across biological membranes: current perspectives and future challenges

Exosomes are small intracellular membrane-based vesicles with different compositions that are involved in several biological and pathological processes. The exploitation of exosomes as drug delivery vehicles offers important advantages compared to other nanoparticulate drug delivery systems such as liposomes and polymeric nanoparticles; exosomes are non-immunogenic in nature due to similar composition as body׳s own cells. In this article, the origin and structure of exosomes as well as their biological functions are outlined. We will then focus on specific applications of exosomes as drug delivery systems in pharmaceutical drug development. An overview of the advantages and challenges faced when using exosomes as a pharmaceutical drug delivery vehicles will also be discussed.

Targeted delivery of siRNA to activated T cells via transferrin-polyethylenimine (Tf-PEI) as a potential therapy of asthma

Asthma is a worldwide health problem. Activated T cells (ATCs) in the lung, particularly T helper 2 cells (Th2), are strongly associated with inducing airway inflammatory responses and chemoattraction of inflammatory cells in asthma. Small interfering RNA (siRNA) as a promising anti-sense molecule can specifically silence inflammation related genes in ATCs, however, lack of safe and efficient siRNA delivery systems limits the application of siRNA as a therapeutic molecule in asthma. Here, we designed a novel pulmonary delivery system of siRNA, transferrin-polyethylenimine (Tf-PEI), to selectively deliver siRNA to ATCs in the lung. Tf-PEI polyplexes demonstrated optimal physicochemical properties such as size, distribution, zeta-potential, and siRNA condensation efficiency. Moreover, in vitro studies showed significantly enhanced cellular uptake and gene knockdown mediated by Tf-PEI polyplexes in human primary ATCs. Biodistribution of polyplexes in a murine asthmatic model confirmed that Tf-PEI polyplexes can efficiently and selectively deliver siRNA to ATCs. In conclusion, the present work proves the feasibility to target ATCs in asthma via Tf receptor. This strategy could potentially be used to design an efficient siRNA delivery system for asthma therapy.

Screening nylon-3 polymers, a new class of cationic amphiphiles, for siRNA delivery

Amphiphilic nucleic acid carriers have attracted strong interest. Three groups of nylon-3 copolymers (poly-β-peptides) possessing different cationic/hydrophobic content were evaluated as siRNA delivery agents in this study. Their ability to condense siRNA was determined in SYBR Gold assays. Their cytotoxicity was tested by MTT assays, their efficiency of delivering Alexa Fluor-488-labeled siRNA intracellularly in the presence and absence of uptake inhibitors was assessed by flow cytometry, and their transfection efficacies were studied by luciferase knockdown in a cell line stably expressing luciferase (H1299/Luc). Endosomal release was determined by confocal laser scanning microscopy and colocalization with lysotracker. All polymers efficiently condensed siRNA at nitrogen-to-phosphate (N/P) ratios of 5 or lower, as reflected in hydrodynamic diameters smaller than that at N/P 1. Although several formulations had negative zeta potentials at N/P 1, G2C and G2D polyplexes yielded >80% uptake in H1299/Luc cells, as determined by flow cytometry. Luciferase knockdown (20–65%) was observed after transfection with polyplexes made of the high molecular weight polymers that were the most hydrophobic. The ability of nylon-3 polymers to deliver siRNA intracellularly even at negative zeta potential implies that they mediate transport across cell membranes based on their amphiphilicity. The cellular uptake route was determined to strongly depend on the presence of cholesterol in the cell membrane. These polymers are, therefore, very promising for siRNA delivery at reduced surface charge and toxicity. Our study identified nylon-3 formulations at low N/P ratios for effective gene knockdown, indicating that nylon-3 polymers are a new, promising type of gene delivery agent.

Poly(ethylene glycol) cross-linked hemoglobin with antioxidant enzymes protects pancreatic islets from hypoxic and free radical stress and extends islet functionality

The objective of this study was to investigate the efficiency of multifunctional poly(ethylene glycol)-based hemoglobin conjugates crosslinked with antioxidant enzymes for their ability to protect an oxygen carrier (hemoglobin) and insulin secreting islets from the combination of hypoxic and free radical stress under simulated transplantation conditions. In this study, RINm5F cells and isolated pancreatic islets were challenged with oxidants (H(2)O(2) or xanthine and xanthine oxidase) and incubated with conjugates (hemoglobin-hemoglobin or superoxide dismutase-catalase-hemoglobin) in normoxia (21% oxygen) or hypoxia (6% or 1% oxygen). Hemoglobin protection, intracellular free radical activity and cell viability in RINm5F cells measured by methemoglobin, dichlorofluorescein-diacetate, and (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay, respectively, showed that cells were better protected by conjugates containing antioxidant enzymes. Insulin secretion from islets and qualitative confocal evaluation of viability showed beta cells were protected by conjugates containing antioxidant enzymes when exposed to induced stress. Our study suggested that antioxidant enzymes play a significant role in hemoglobin protection and thus extended cell protection.

Hemoglobin conjugates with antioxidant enzymes (hemoglobin-superoxide dismutase-catalase) via poly(ethylene glycol) crosslinker for protection of pancreatic beta RINm5F cells in hypoxia

A low p50 hemoglobin (Hb) (p50 indicates O(2) tension at which Hb is half-saturated)-based oxygen carrier conjugated to antioxidant enzymes via dicarboxymethylated poly(ethylene glycol) (PEG) linker may have the beneficial effect in protecting pancreatic beta cells from severe hypoxia at transplantation sites. In this study, the oxygen dissociation curves, Hill plots, Bohr Effect, and oxygen content of Hb conjugates were measured. The protective effect due to incubation of Hb-conjugates (Hb/PEG molar ratio 1:10) with pancreatic beta cells (RINm5F) against hypoxia (6%, 3%, and 1% oxygen) was evaluated by an MTT assay and confocal microscopy. Quantitatively, Hb conjugates with antioxidant enzymes offered statistically significant protection (p<0.01, increased viability ∼80%) from hypoxia compared to control cells in 1% oxygen environment. Confocal images also showed that the low p50 Hb conjugates with antioxidants protected RINm5F cells from hypoxia.

Synthesis and characterization of hemoglobin conjugates with antioxidant enzymes via poly(ethylene glycol) cross-linker (Hb-SOD-CAT) for protection from free radical stress

Hemoglobin (Hb) conjugated with the antioxidant enzymes (SOD and CAT), by employing dicarboxymethylated poly(ethylene glycol), was designed for protection of hemoglobin against free radicals. In this study, the conjugation process was confirmed by employing SDS-PAGE and SEC techniques. The average molecular weight of the conjugates was estimated to be around 1000 kDa. The enzymatic activities of the SOD and CAT in the conjugates (Hb-SOD-CAT) after conjugation were found to retain greater than 70% and 90% of the original bioactivity. Results show that antioxidant enzymes helped minimize methemoglobin (non-carrier of oxygen) formation during the conjugation process and also during storage at 4°C over a period of 1 month. In summary, the optimized (1:10 Hb/PEG) crosslinked conjugates with antioxidant enzymes showed protective properties from severe free radical stresses when incubated with hydrogen peroxide (0.1 and 1 mM) and xanthine (1 mM)/xanthine oxidase (10 and 20 mU/ml) system.

Evaluation of nose-only aerosol inhalation chamber and comparison of experimental results with mathematical simulation of aerosol deposition in mouse lungs

In vivo small rodent efficacy testing of new synthetic and biological molecules for the pulmonary route requires an efficient delivery device. For this purpose, a nose-only inhalation chamber was used to deliver aerosolized aqueous compounds to the respiratory tract of mice. The aim of the study was to determine the efficiency of dose delivery and deposition in the lungs of the mice using this chamber. A secondary goal was to compare the experimental lung deposition results with values predicted from mathematical simulation. Experimental tests were conducted by generating aerosols of a radiolabeled formulation of human serum albumin (HSA) with a mass median aerodynamic diameter (MMAD) of 3.9 +/- 0.5 microm and a geometric standard deviation (GSD) of 1.43 +/- 0.05 using PARI LC STAR jet nebulizers. Based on the total activity placed in the nebulizer, the chamber delivered 0.108 +/- 0.027% to the mice and 0.0087 +/- 0.0021% to the lungs of the mice. In vivo lung deposition was found to be 8.19 +/- 3.56% of total activity deposited in the mouse. Mathematical simulation predictions ranged between 5.89 and 4.40% for various breathing patterns, and did not differ significantly from the in vivo results (p > 0.10). These results provide important quantitative information relevant to aerosol delivery experiments in mouse models. Our results also suggest that the nose-only inhalation chamber would benefit from significant changes to increase the efficiency of deposition in mice such that it can be used for nebulization of expensive therapeutic drugs.