Lyophilization as an effective tool to develop AAV8 gene therapy products for refrigerated storage.

Recombinant adeno-associated virus (rAAV) has emerged as the leading gene delivery platform for treatment of monogenic disorders. Currently, for clinical and commercial products, rAAVs are typically formulated and stored below -65 °C as frozen liquid. Their long-term storage is often far from ideal because it may result in shorter drug product (DP) shelf-life compared to recombinant protein-based biologics, and also presents challenges for supply chain and inventory management. Consequently, there is great interest in developing robust lyophilized AAV DPs that are stable at 2 to 8 °C. In this study, we evaluated formulation excipients required for stable lyophilized AAV8 products including buffers, salts, cryoprotectants/lyoprotectants, surfactants, and bulking agents, and optimized the concentrations and ratios between the excipients. This led to the identification of the lead formulation that demonstrated short-term in-solution stability at 25 °C and, upon lyophilization, sufficient long-term stability at 2 to 8 °C. Our study demonstrated that, in the presence of 110 mM salts, mannitol can serve as an effective bulking agent with the appropriate formulation and lyophilization process design, and the sucrose to mannitol ratio is critical to maintain the stability and cake appearance of the lyophilized AAV8 DP. Thorough characterization of the effect of formulation components on the properties and quality of the lyophilized DP led to an optimized AAV8 lyophilized DP. This approach could be applied to streamline the future development of lyophilized AAV gene therapy products with various target transgenes and capsid serotypes.

UV resonance Raman and DFT studies of arginine side chains in peptides: insights into arginine hydration.

We examined the UV resonance Raman (UVRR) spectra of four models of the Arg side chain, guanidinium (Gdn), ethylguanidinium (EG), arginine (Arg), and Ac-Arg-OMe (AAO) in H2O and D2O, in order to identify spectral markers that report on the environment of the Arg side chain. To elucidate the resonance Raman enhancement mechanism of the Arg side chain, we used density functional theory (DFT) to calculate the equilibrium geometries of the electronic ground state and the first excited state. We determined the vibrational mode frequencies of the ground state and the first derivative of the first electronic excited state potential energy with respect to each vibrational normal mode of the electronic ground state at the electronic ground state equilibrium geometry. The DFT calculations and the potential energy distributions reveal that, in addition to the Gdn group C-N stretching vibrations, the C-N bond stretching vibration of the Gdn group-methylene linkage is also strongly resonance-enhanced in EG, Arg, and AAO. From the UVRR spectra, we find that the Raman cross section and frequency of the ~1170 cm(-1) vibration of the Arg side chain depends on its hydration state and can be used to determine the hydration state of the Arg side chain in peptides and proteins. We examined the hydration of the Arg side chain in two polyAla peptides and found that in the α-helical conformation the Arg side chain in the AEP peptide (sequence: A9RA3EA4RA2) is less hydrated than that in the AP peptide (sequence: A8RA4RA4RA2).

A primary care focus on the treatment of patients with major depressive disorder.

Major depressive disorder (MDD) is a common psychiatric illness affecting nearly 20% of adults in the United States at least once during their lifetime. MDD is frequently diagnosed and treated in the primary care setting. Management of the disease may be complicated by patients and family members feeling stigmatized by the diagnosis and not understanding that depression is a treatable medical illness, which, in turn, fosters low rates of adherence to treatment recommendations. Incomplete or delayed response to treatment, adverse events associated with antidepressants and medical or psychiatric comorbidities also interfere with optimal depression management. This article presents an overview of diagnostic and treatment guidelines for MDD and focuses on challenges encountered by primary care physicians. The role of antidepressant medications, psychotherapy and nonpharmacologic interventions for the treatment of patients with MDD is described, and factors influencing treatment selection, such as adverse event profiles and patient characteristics, are examined.

Impact of data from recent clinical trials on strategies for treating patients with type 2 diabetes mellitus.

Type 2 diabetes is associated with increased risk for the development of cardiovascular disease (CVD) secondary to hyperglycemia's toxicity to blood vessels. The escalating incidence of CVD among patients with type 2 diabetes has prompted research into how lowering glycated hemoglobin (HbA(1c)) may improve CVD-related morbidity and mortality. Data from recent studies have shown that some patients with type 2 diabetes actually have increased mortality after achieving the lowest possible HbA(1c) using intensive antidiabetes treatment. Multiple factors, such as baseline HbA(1c), duration of diabetes, pancreatic beta-cell decline, presence of overweight/obesity, and the pharmacologic durability of antidiabetes medications influence diabetes treatment plans and therapeutic results. Hypertension and dyslipidemia are common comorbidities in patients with type 2 diabetes, which impact the risk of CVD independently of glycemic control. Consideration of all of these risk factors provides the best option for reducing morbidity and mortality in patients with type 2 diabetes. Based on the results of recent trials, the appropriate use of current antidiabetes therapies can optimize glycemic control, but use of intensive glucose-lowering therapy will need to be tailored to individual patient needs and risks.

Solvent-dependent cage dynamics of small nonpolar radicals: lessons from the photodissociation and geminate recombination of alkylcobalamins.

Time-resolved transient absorption spectroscopy was used to investigate the primary geminate recombination and cage escape of alkyl radicals in solution over a temperature range from 0 to 80 degrees C. Radical pairs were produced by photoexcitation of methyl, ethyl, propyl, hexylnitrile, and adenosylcobalamin in water, ethylene glycol, mixtures of water and ethylene glycol, and sucrose solutions. In contrast to previous studies of cage escape and geminate recombination, these experiments demonstrate that cage escape for these radical pairs occurs on time scales ranging from a hundred picoseconds to over a nanosecond as a function of solvent fluidity and radical size. Ultrafast cage escape (<100 ps) is only observed for the methyl radical where the radical pair is produced through excitation to a directly dissociative electronic state. The data are interpreted using a unimolecular model with competition between geminate recombination and cage escape. The escape rate constant, k(e), is not a simple function of the solvent fluidity (T/eta) but depends on the nature of the solvent as well. The slope of k(e) as a function of T/eta for the adenosyl radical in water is in near quantitative agreement with the slope calculated using a hydrodynamic model and the Stokes-Einstein equation for the diffusion coefficients. The solvent dependence is reproduced when diffusion constants are calculated taking into account the relative volume and mass of both solvent and solute using the expression proposed by Akgerman (Akgerman, A.; Gainer, J. L. Ind. Eng. Chem. Fundam. 1972, 11, 373-379). Rate constants for cage escape of the other radicals investigated are consistently smaller than the calculated values suggesting a systematic correction for radical size or coupled radical pair motion.