Michael Jay

Preparation and characterization of novel coenzyme Q10 nanoparticles engineered from microemulsion precursors

The purpose of these studies was to prepare and characterize nanoparticles into which Coenzyme Q10 (CoQ10) had been incorporated (CoQ10-NPs) using a simple and potentially scalable method. CoQ10-NPs were prepared by cooling warm microemulsion precursors composed of emulsifying wax, CoQ10, Brij 78, and/or Tween 20. The nanoparticles were lyophilized, and the stability of CoQ10-NPs in both lyophilized form and aqueous suspension was monitored over 7 days. The release of CoQ10 from the nanoparticles was investigated at 37°C. Finally, an in vitro study of the uptake of CoQ10-NPs by mouse macrophage, J774A.1, was completed. The incorporation efficiency of CoQ10 was approximately 74%±5%. Differential Scanning Calorimetry (DSC) showed that the nanoparticle was not a physical mixture of its individual components. The size of the nanoparticles increased over time if stored in aqueous suspension. However, enhanced stability was observed when the nanoparticles were stored at 4°C. Storage in lyophilized form demonstrated the highest stability. The in vitro release profile of CoQ10 from the nanoparticles showed an initial period of rapid release in the first 9 hours followed by a period of slower and extended release. The uptake of CoQ10-NPs by the J774A.1 cells was over 4-fold higher than that of the CoQ10-free nanoparticles (P<.05). In conclusion, CoQ10-NPs with potential application for oral CoQ10 delivery were engineered readily from microemulsion precursors.

Enhanced chemotaxis and superoxide anion production by polymorphonuclear leukocytes from nicotine-treated and smoke-exposed rats

Although previous studies have shown that polymorphonuclear leukocytes (PMNs) exposed to nicotine in vitro exhibit enhanced superoxide anion generation and chemotactic responses, it is not known whether in vivo exposure to the alkaloid causes the same alterations in PMN function. Accordingly, this study evaluated superoxide anion generation evoked by phorbol myristate acetate (PMA) and chemotactic responses to formylmethionylleucylphenylalanine (fMLP) in PMNs isolated from rats treated acutely or subchronically with nicotine and from rats chronically exposed to cigarette smoke. Acute or subchronic (twice daily for 7 days) i.p. injection of 0.2 or 0.02 mg/kg nicotine potentiated PMA-induced superoxide anion generation by PMNs. Similarly, acute i.p. injection of 0.2 mg/kg nicotine or subchronic treatment with 0.02 mg/kg nicotine potentiated fMLP-induced chemotaxis. Subchronic treatment with 0.2 mg/kg of the alkaloid blunted fMLP-induced chemotaxis, in contrast to the potentiating actions of the lower dose. Treatment with nicotine mimicked the effects of tobacco smoke exposure. A 15-week exposure regimen to either sidestream and mainstream smoke from University of Kentucky 2R1 reference cigarettes potentiated PMA-induced superoxide anion generation. Mainstream but not sidestream smoke also enhanced chemotactic responses to fMLP. Viewed collectively, these observations indicate that in vivo exposure to nicotine or to tobacco smoke augment PMN superoxide anion generation and chemotactic responses to selected stimuli and thus implicate such adverse actions of smoking on PMN function in certain pathologies associated with excessive tobacco smoke exposure.

Purification of Proteins Using Foam Fractionation

Purification is an important step in the production of pharmaceuticals from recombinant proteins. The characteristics of industrial-scale purification schemes, such as conventional chromatography, have a significant impact on the cost of production. Foam fractionation, a novel separation technique based upon the differences in affinities of components for the gas/aqueous interface of a foam, has the potential to be a cost-effective component in a purification scheme. This review covers some of the more recent studies in understanding the process and applications of foam fractionation in protein-containing systems with special attention to the requirements of pharmaceutical products.

Disposition of radiolabelled suppositories in humans

The disposition of Witepsol H 15 suppositories radiolabelled with [99m Tc] technetium hydroxymethyldiphosphonate was studied after rectal administration in volunteers. The migration of the radiolabel was monitored continuously by external scintigraphy. The resulting scintiphotos were superimposed on lower GI radiographs to determine the extent of spreading of the dosage form in the rectum. The dosage form migrated approximately 5−7 cm into the rectum in nearly all of the studies and was, in general, confined to the lower and middle regions of the rectum. Since the venous supply to the lower rectum leads primarily to the inferior vena cava, the data presented here indicate that the metabolism of drugs sensitive to the ‘first‐pass’ effect may be partially avoided by their rectal administration.

Correlation of Ibuprofen Bioavailability with Gastrointestinal Transit by Scintigraphic Monitoring of 171Er-Labeled Sustained-Release Tablets

External gamma scintigraphy was used to monitor the gastrointestinal (GI) transit of radiolabeled sustained-release tablets containing 800 mg ibuprofen in eight fasted healthy volunteers. Ibuprofen serum concentrations were determined from blood samples drawn sequentially over a 24-hr period. Serum concentrations and related parameters were correlated to the position of the dosage form in the GI tract from the scintiphotos. The sustained-release tablets were radiolabeled intact utilizing a neutron activation procedure, by incorporating 0.18% of 170Er2O3 (enriched to >96% 170Er) into the bulk formulation. After manufacture of the final dosage forms, the tablets were irradiated in a neutron flux (4.4 × 1013 n/cm2 · sec) for 2 min, converting the stable 170Er to radioactive 171Er (t1/2 = 7.5 hr). Each tablet contained 50 µCi of 171Er at the time of administration. The scintigraphy studies suggested that the greatest proportion of ibuprofen was absorbed from this dosage form while the tablet was in the large bowel. The dosage forms eroded slowly in the small bowel and appeared to lose their integrity in the large bowel. In vitro studies showed only minimal effects of the neutron irradiation procedure on the dosage form performance.

Behavior of partially fluorinated carboxylic acids at the air-water interface

Abstract Langmuir isotherms were recorded for 1-(perfluorobutyl)undecanoic acid (F 3 C(CF 2 ) 3 (CH 2 ) 10 CO 2 H), 1-(perfluorohexyl)undecanoic acid (F 3 C(CF 2 ) 5 (CH 2 ) 10 CO 2 H) and 1-(perfluorooctyl)undecanoic acid (F 3 C(CF 2 ) 7 (CH 2 ) 10 CO 2 H), their hydrocarbon analog, perfluorododecanoic and perfluorotetradecanoic acid after spreading onto hydrochloric acid (pH=1.9–2.0) at 32°C. All acids formed stable monolayers at the air–water interface. 1-(Perfluorobutyl)undecanoic acid shows some similarity to the compression isotherm of tetradecanoic acid while lacking the phase transition of pentadecanoic acid. The isotherm for 1-(perfluorohexyl)undecanoic acid shows a temperature-dependent phase transition similar to the liquid expanded-liquid condensed transition of pentadecanoic acid. The π-A isotherm of 1-(perfluorooctyl)undecanoic acid resembles the highly condensed monolayers of hepta- and nonadecanoic acid. Thus, the partially fluorinated acids seem to exhibit isotherm characteristics similar to hydrocarbon acids with shorter chain lengths. The three partially fluorinated acids have a higher limiting area compared to hydrocarbon and perfluorocarbon acids, which may be atributed to the strong dipole moment of the CF 2 CH 2  linkage. Within this series of partially fluorinated carboxylic acids, the limiting area decreases with chain lengthening and a higher degree of fluorination. The collapse pressures of the fluorinated acids are smaller compared to their respective hydrocarbon analog.

Tumor uptake of 67Ga-carrying liposomes

The in vivo distribution, excretion, and tumor localization of liposome-encapsulated 67Ga in normal and Ehrlich tumor (solid form)-bearing mice were studied. In normal mice, multilamellar vesicles (MLVs) were taken up mainly by the liver and spleen, whereas small unilamellar vesicles (SUVs) exhibited a broader tissue distribution. When 67Ga was encapsulated in MLVs or SUVs, the excretion of the radiotracer in the urine and feces was less than that observed for free tracer at 72 h after i.v. administration. In tumor-bearing mice, SUVs were found to accumulate preferentially in tumors. The tumor uptake of neutral, positive, and negative SUVs was 10%–13% of the administered dose per gram of tumor tissue at 24 h after their injection. These values were about three times higher than those found for free 67Ga-nitrilotriacetic acid (67Ga-NTA) or 67Ga-citrate. Significant differences in tumor uptake due to different surface charges of liposomes were not observed. Enhanced tumor-to-blood and tumor-to-muscle ratios were also observed at 24 h after injection. These results suggest that 67Ga-carrying liposomes may be a useful for tumor imaging.

The effect of food on gastrointestinal (GI) transit of sustained-release ibuprofen tablets as evaluated by gamma scintigraphy

The GI transit of radiolabeled sustained-release ibuprofen 800-mg tablets in eight healthy, fed volunteers was monitored using external gamma scintigraphy. Ibuprofen serum concentrations were determined from blood samples drawn over 36 hr following dosing. Sustained-release ibuprofen tablets containing 0.18% of 170Er2O3 (>96% 170Er) in the bulk formulation were manufactured under pilot-scale conditions and were radiolabeled utilizing a neutron activation procedure which converted stable 170Er to radioactive 171Er (t1/2 = 7.5 hr). At the time of dosing, each tablet contained 50 µCi of 171Er. Dosage form position was reported at various time intervals. In five subjects the sustained-release tablet remained in the stomach and eroded slowly over 7–12 hr, resulting in gradual increases in small bowel radioactivity. In the remaining three subjects, the intact tablet was ejected from the stomach and a gastric residence time of approximately 4 hr was measured. This is in marked contrast to a previous study conducted in fasted volunteers in which gastric retention time ranged from 10 to 60 min. Differences in GI transit between fed and fasted volunteers had little effect on ibuprofen bioavailability. AUC and Tmax were unaltered and Cmax was increased by 24%, which is in agreement with results from a previous, crossover-design food effect study.

Nicotine potentiates superoxide anion generation by human neutrophils

Cytotoxic neutrophil-derived oxygen radicals have been implicated in the pathogenesis of a variety of cardiovascular, pulmonary, and neoplastic disorders for which cigarette smoking is a prominent risk factor. Although nicotine alone failed to provoke neutrophil oxidative metabolism, the alkaloid caused dose-dependent (0.1 to 10 microM) potentiation of superoxide anion release induced by either phorbol myristate acetate or N-formyl-methionyl-leucyl-phenylalanine. The potentiating effect of nicotine was not attenuated by either atropine or hexamethonium nor was it mimicked by acetylcholine, suggesting involvement of noncholinergic receptors or a membrane-fluidizing effect of the alkaloid. Nicotine-induced exacerbation of neutrophil superoxide anion production may be involved with the enhanced risk of cardiovascular, pulmonary, or neoplastic disease in individuals who smoke.

Novel Ethanol-in-Fluorocarbon Microemulsions for Topical Genetic Immunization

AbstractPurpose. Traditionally, vaccines have been administered by needle injection. Topical immunization through the intact skin with either protein- or DNA-based vaccines has attracted much attention recently. We sought to enhance the immune responses induced by DNA-based vaccines after topical application by developing novel ethanol-in-fluorocarbon (E/F) microemulsion systems to aid in the delivery of plasmid DNA (pDNA). Methods. Ten different fluorosurfactants were selected or synthesized and screened by pseudo-phase-diagram construction for their ability to form E/F microemulsions. Plasmid DNA was successfully incorporated into E/F microemulsions using several different fluorosurfactants and perfluorooctyl bromide as the continuous fluorocarbon phase. For several reasons, Zonyl® FSN-100 (an ethoxylated nonionic fluorosurfactant) was selected for further studies. In vivo studies were performed in mice to assess pDNA expression in skin and immunologic responses after topical application of this system using a luciferase-encoding plasmid (CMV-luciferase) and a CMV-β-galactosidase-encoding plasmid, respectively. Results. Plasmid DNA incorporated into E/F microemulsion using FSN-100 as the surfactant was found to be stable. After topical application of this E/F microemulsion system, significant enhancements in luciferase expression and antibody and T-helper type-1 biased immune responses were observed relative to those of “naked” pDNA in saline or ethanol. For example, with the E/F microemulsion system, the specific serum IgG and IgA titers were increased by 45-fold and over 1000-fold, respectively. Conclusion. A novel fluorocarbon-based microemulsion system for potential DNA vaccine delivery was developed.