Beneficial and Adverse Effects of an LXR Agonist on Human Lipid and Lipoprotein Metabolism and Circulating Neutrophils.

The development of LXR agonists for the treatment of coronary artery disease has been challenged by undesirable properties in animal models. Here we show the effects of an LXR agonist on lipid and lipoprotein metabolism and neutrophils in human subjects. BMS-852927, a novel LXRß-selective compound, had favorable profiles in animal models with a wide therapeutic index in cynomolgus monkeys and mice. In healthy subjects and hypercholesterolemic patients, reverse cholesterol transport pathways were induced similarly to that in animal models. However, increased plasma and hepatic TG, plasma LDL-C, apoB, apoE, and CETP and decreased circulating neutrophils were also evident. Furthermore, similar increases in LDL-C were observed in normocholesterolemic subjects and statin-treated patients. The primate model markedly underestimated human lipogenic responses and did not predict human neutrophil effects. These studies demonstrate both beneficial and adverse LXR agonist clinical responses and emphasize the importance of further translational research in this area.

Dry powder nasal vaccines as an alternative to needle-based delivery.

Drug delivery to the nasal cavity has been achieved using a variety of systems. Dry powder vaccines offer the advantages of chemical and physical stability in comparison to liquid formulations. An intranasal vaccine can elicit both a local and systemic immune response. Mucoadhesive compounds can extend the residence time for powder formulations on the nasal mucosa, potentially increasing the immune response. Manufacture and characterization of a formulation containing particles of a dry powder vaccine are discussed.

Calibration of the Andersen cascade impactor for the characterization of nasal products.

Current cascade impactor protocols do not completely rule out nasal preparations entering the lower respiratory tract. A modified cascade impactor (MCI) was developed to characterize the particle size fraction capable of deposition in the lower respiratory tract. This is an important measure of the potential for delivery to a site which is not the route of administration, and which could lead to potential toxicity. Monodisperse aerosols were utilized to calibrate the Stage -2 and Stage -0 of an Andersen Mk II nonviable cascade impactor at 15 L per minute flow rate. While these sampling conditions are beyond the normal working range of impactor theory in practice the instrument was shown to discriminate the designated particle sizes sampled. This novel setup extended the upper limit of the range of particle sizes that the cascade impactor can characterize from 8.7 to 16.5 microm.

Novel dry powder preparations of whole inactivated influenza virus for nasal vaccination.

The purpose of these studies was to enhance mucosal and systemic antibody production in response to increased local residence time of a whole inactivated influenza virus administered as a dry powder nasal vaccine formulation. Spray-freeze-drying (SFD) particles suitable for nasal delivery were characterized for physico-chemical properties and stability. Mucoadhesive compounds (MA) were characterized for their effects on nasal residence time of vaccine powders in rats compared with published in vitro data and elicited immune responses. SFD particles (D(50) = 26.9 microm) were spherical with a specific surface area of 1.25 m(2)/g. Thermal analysis indicated SFD powders were amorphous and demonstrated improved stability with respect to liquid formulations under various storage conditions. In vitro physico-chemical studies and in vivo scintigraphic imaging experiments indicated sodium alginate (SA) and carboxymethylcellulose-high molecular weight (CMC-HMW) powder formulations most significantly increased residence time in Brown Norway rats. Intramuscular delivery provided equivalent serum antibody titers to intranasal (IN) powder without MA, in the presence of CMC-HMW, SA, and hydroxypropyl methylcellulose (HPMC-HMW) after initial dosing and all formulations except IN powder with chitosan after boosting. IN liquid provided equivalent serum antibody titers to all IN powders after the initial vaccination and significantly greater serum antibody titers than IN powder with chitosan after boosting. Trends were consistent between residence time studies and immune response; however, no statistically significant differences between powder and liquid formulations were observed. It was concluded that enhanced serum and mucosal antibody responses were elicited by a dry powder nasal vaccine, specifically, administered in the presence of sodium alginate.

Formulation of a dry powder influenza vaccine for nasal delivery.

The purpose of this research was to prepare a dry powder vaccine formulation containing whole inactivated influenza virus (WIIV) and a mucoadhesive compound suitable for nasal delivery. Powders containing WIIV and either lactose or trehalose were produced by lyophilization. A micro-ball mill was used to reduce the lyophilized cake to sizes suitable for nasal delivery. Chitosan flakes were reduced in size using a cryo-milling technique. Milled powders were sieved between 45 and 125 microm aggregate sizes and characterized for particle size and distribution, morphology, and flow properties. Powders were blended in the micro-ball mill without the ball. Lyophilization followed by milling produced irregularly shaped, polydisperse particles with a median primary particle diameter of approximately 21 microm and a yield of approximately 37% of particles in the 45 to 125 microm particle size range. Flow properties of lactose and trehalose powders after lyophilization followed by milling and sieving were similar. Cryo-milling produced a small yield of particles in the desired size range (<10%). Lyophilization followed by milling and sieving produced particles suitable for nasal delivery with different physicochemical properties as a function of processing conditions and components of the formulation. Further optimization of particle size and morphology is required for these powders to be suitable for clinical evaluation.

Formulation of a dry powder influenza vaccine for nasal delivery.

The purpose of this research was to prepare a dry powder vaccine formulation containing whole inactivated influenza virus (VIIV) and a mucoadhesive compound suitable for nasal delivery. Powders containing WIIV and either lactose or trehalose were produced by lyophilization. A micro-ball mill was used to reduce the lyophilized cake to sizes suitable for nasal delivery. Chitosan flakes were reduced in size using a cryo-milling technique. Milled powders were sieved between 45 and 125 µm aggregate sizes and characterized for particle size and distribution, morphology, and flow properties. Powders were blended in the micro-ball mill without the ball. Lyophilization followed by milling produced irregularly shaped, polydisperse particles with a median primary particle diameter of ≈21 µm and a yield of ≈37% of particles in the 45 to 125 µm particle size range. Flow properties of lactose and trehalose powders after lyophilization followed by milling and sieving were similar. Cryo-milling produced a small yield of particles in the desired size range (<10%). Lyophilization followed by milling and sieving produced particles suitable for nasal delivery with different physicochemical properties as a function of processing conditions and components of the formulation. Further optimization of particle size and morphology is required for these powders to be suitable for clinical evaluation.

A novel dry powder influenza vaccine and intranasal delivery technology: induction of systemic and mucosal immune responses in rats.

Intranasal (i.n.) vaccination represents an attractive non-invasive alternative to needle-based injection and provides superior protection at mucosal surfaces. However, new formulations are needed to improve efficacy and reduce the refrigerated storage and distribution requirements associated with standard liquid vaccines. Here, we describe a powder formulation of whole inactivated influenza virus and a novel i.n. delivery platform. The powder-formulated vaccine elicited a significant serum antibody response in rats that was at least as strong as that provided by the liquid vaccine administered i.n. or via intramuscular (i.m.) injection. Significant nasal IgA responses were also observed solely after i.n. delivery. This study demonstrates for the first time the generation of potent nasal mucosal and systemic immune responses using an i.n. delivered influenza vaccine powder and suggests an alternative approach to vaccination against influenza and other infectious diseases.

Spray-dried chitinosans. Part I: preparation and characterization.

PURPOSE: Physicochemical and micromeritic characterization of chitinosans. METHODS: Chitinosans subjected to N-deacetylation and depolymerization were characterized for degree of N-deacetylation (DD), molecular weight (MW), pK(a), particle size determination and morphology, tap/bulk density measurements, surface area determinations, and determination of flow properties. RESULTS: The chitinosan DDs and MWs were dependent on the processing conditions and ranged from 66 to 89% and 2-522 kDa, respectively. Chitinosan particle sizes and shapes were dependent on drying conditions (range 8-465 microm). Spray-dried chitinosans were spherical and had smaller particle sizes than the non-spray-dried materials which were irregularly shaped particles. Higher density values were obtained for processed materials than those for the raw material. Lower specific surface areas were observed for non-spray-dried chitinosans (0.28-1.59 m(2)/g) than for spray-dried chitinosans (0.74-3.01 m(2)/g). Weight variation of chitinosan tablets indicated that spray-dried chitinosans possessed improved flow characteristics as compared with tray-dried chitinosans. CONCLUSIONS: The effect of drying method employed in chitinosan manufacture, i.e. spray versus tray drying, on the physicochemical and micromeritic properties of the resultant chitinosans were evaluated. Although the drying methods did not significantly influence the physicochemical properties, they affected the micromeritic properties of the resultant chitinosans.

Spray-dried chitinosans. Part II: in vitro drug release from tablets made from spray-dried chitinosans.

PURPOSE: Application of spray-dried chitinosans as excipients for use in drug delivery systems was explored. METHODS: Spray- and tray-dried chitinosans previously N-deacetylated and depolymerized were used. Directly compressed tablets (200mg) containing tetracycline, chitinosan, and magnesium stearate were prepared. The tablets were characterized for dimensions, weight, friability, crushing strengths, disintegration, and dissolution. RESULTS: The tablet weights, thickness, and diameters were not affected by the chitinosan selected (P>0.05). Friability of tablets containing tray-dried chitinosans was generally higher (and crushing strengths were lower) than tablets containing spray-dried chitinosans. Chitinosan molecular weight, degree of N-deacetylation, and drying method used, significantly affected crushing strengths (P<0.0001). Disintegration times were affected only by the type of chitinosan (P<0.0001) but not by the drying method used (P>0.9). Dissolution from tablets was significantly affected by the chitinosan type (P<0.025), but not affected by the drying method (P>0.5). CONCLUSIONS: Spray drying improved binding functionality of chitinosans, thereby enhancing the tablet crushing strength; however, friability, disintegration, and dissolution profiles were not significantly affected. The data obtained from this study support the usefulness of spray-dried chitinosans as excipients for use in drug delivery systems.