The Influence of Secondary Processing on the Structural Relaxation Dynamics of Fluticasone Propionate

This study investigated the structural relaxation of micronized fluticasone propionate (FP) under different lagering conditions and its influence on aerodynamic particle size distribution (APSD) of binary and tertiary carrier-based dry powder inhaler (DPI) formulations. Micronized FP was lagered under low humidity (LH 25 C, 33% RH [relative humidity]), high humidity (HH 25°C, 75% RH) for 30, 60, and 90 days, respectively, and high temperature (HT 60°C, 44% RH) for 14 days. Physicochemical, surface interfacial properties via cohesive-adhesive balance (CAB) measurements and amorphous disorder levels of the FP samples were characterized. Particle size, surface area, and rugosity suggested minimal morphological changes of the lagered FP samples, with the exception of the 90-day HH (HH90) sample. HH90 FP samples appeared to undergo surface reconstruction with a reduction in surface rugosity. LH and HH lagering reduced the levels of amorphous content over 90-day exposure, which influenced the CAB measurements with lactose monohydrate and salmeterol xinafoate (SX). CAB analysis suggested that LH and HH lagering led to different interfacial interactions with lactose monohydrate but an increasing adhesive affinity with SX. HT lagering led to no detectable levels of the amorphous disorder, resulting in an increase in the adhesive interaction with lactose monohydrate. APSD analysis suggested that the fine particle mass of FP and SX was affected by the lagering of the FP. In conclusion, environmental conditions during the lagering of FP may have a profound effect on physicochemical and interfacial properties as well as product performance of binary and tertiary carrier-based DPI formulations.

Electronic supplementary material

The online version of this article (doi:10.1208/s12249-014-0222-8) contains supplementary material, which is available to authorized users.KEY WORDS: cohesive-adhesive balance, laagering, mechanical activation, particle adhesion, process-induced structural disorder     

A role for anions in ATP synthesis and its molecular mechanistic interpretation

ATP, the ‘universal biological energy currency’, is synthesized by utilizing energy either from oxidation of fuels or from light, via the process of oxidative and photo-phosphorylation respectively. The process is mediated by the enzyme F₁F₀-ATP synthase, using the free energy of ion gradients in the final energy catalyzing step, i.e., the synthesis of ATP from ADP and inorganic phosphate (P_i). The details of the molecular mechanism of ATP synthesis are among the most important fundamental issues in biology and hence need to be properly understood. In this work, a role for anions in making ATP has been found. New experimental data has been reported on the inhibition of ATP synthesis at nanomolar concentrations by the potent, specific anion channel blockers 4,4′-diisothiocyanostilbene-2, 2′-disulphonic acid (DIDS) and tributyltin chloride (TBTCl). Based on these inhibition studies, attention has been drawn to anion translocation (in addition to proton translocation) as a requirement for ATP synthesis. The type of inhibition has been quantified and an overall kinetic scheme for mixed inhibition that explains the data has been evolved. The experimental data and the type of inhibition found have been interpreted in the light of the torsional mechanism of energy transduction and ATP synthesis (Nath J Bioenerg Biomembr 42:293–300, 2010a; J Bioenerg Biomembr 42:301–309, 2010b). This detailed and unified mechanism resolves long-standing problems and inconsistencies in the first theories (Slater Nature 172:975–978, 1953; Williams J Theor Biol 1:1–17, 1961; Mitchell Nature 191:144–148, 1961; Mitchell Biol Rev 41:445–502, 1966), makes several novel predictions that are experimentally verifiable (Nath Biophys J 90:8–21, 2006a; Process Biochem 41:2218–2235, 2006b), and provides us with a new and fruitful paradigm in bioenergetics. The interpretation presented here provides intelligent answers to the unexplained existing results in the literature. It is shown that mechanistic interpretation of the experimental data requires substantial addition to available conceptual foundations such that present concepts, theories, and mechanisms must be revised.     

Effect of SDS on human hair: Study on the molecular structure and morphology

This paper presents a model study to understand the effect of surfactants on the physicochemical properties of human hair. FT‐IR ATR spectroscopy has been employed to understand the chemical changes induced by sodium dodecyl sulfate (SDS) on human scalp hair. In particular, the SDS induced changes in the secondary structure of protein present in the outer protective layer of hair, i.e. cuticle, have been investigated. Conformational changes in the secondary structure of protein were studied by curve fitting of the amide I band after every phase of SDS treatment. It has been found that SDS brings rearrangements in the protein backbone conformations by transforming β ‐sheet structure to random coil and β ‐turn. Additionally, AFM and SEM studies were carried out to understand the morphological changes induced on the hair surface. SEM and AFM images demonstrated the rupture and partial erosion of cuticle sublayers. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Insulin receptor substrate protein 53kDa (IRSp53) is a negative regulator of myogenic differentiation

Fusion of mononucleated myoblasts to generate multinucleated myotubes is a critical step in skeletal muscle development. Filopodia, the actin cytoskeleton based membrane protrusions, have been observed early during myoblast fusion, indicating that they could play a direct role in myogenic differentiation. The control of filopodia formation in myoblasts remains poorly understood. Here we show that the expression of IRSp53 (Insulin Receptor Substrate protein 53kDa), a known regulator of filopodia formation, is down-regulated during differentiation of both mouse primary myoblasts and a mouse myoblast cell line C2C12. Over-expression of IRSp53 in C2C12 cells led to induction of filopodia and decrease in cell adhesion, concomitantly with inhibition of myogenic differentiation. In contrast, knocking down the IRSp53 expression in C2C12 cells led to a small but significant increase in myotube development. The decreased cell adhesion of C2C12 cells over-expressing IRSp53 is correlated with a reduction in the number of vinculin patches in these cells. Mutations in the conserved IMD domain (IRSp53 and MIM (missing in metastasis) homology domain) or SH3 domain of IRSp53 abolished the ability of this protein to inhibit myogenic differentiation and reduce cell adhesion. Over-expression of the IMD domain alone was sufficient to decrease the cell-extracellular matrix adhesion and to inhibit myogenesis in a manner dependent on its function in membrane shaping. Based on our data, we propose that IRSp53 is a negative regulator of myogenic differentiation which correlates with the observed down regulation of IRSp53 expression during myoblast differentiation to myotubes.     

Expression of Heat Shock Protein 70 Gene and Its Correlation with Inflammatory Markers in Essential Hypertension

Objectives

Hypertension is characterized by systemic high blood pressure and is the most common and important risk factor for the development of cardiovascular diseases. Studies have shown that the circulating levels of certain inflammatory markers such as tumor necrosis factor-alpha (TNF-alpha), interlukin-6 (IL-6), c-reactive protein (CRP), and tumor suppressor protein-53 (p53) are upregulated and are independently associated with essential hypertension. However, mechanism of increase in the levels of HSP70 protein is not clear. No such studies are reported in the blood circulation of patients with essential hypertension. In the present study, we investigated the expression of circulating HSP70 at mRNA and protein levels and its relationship with other inflammatory markers in patients with essential hypertension.

Materials and Methods

We recruited 132 patients with essential hypertension and 132 normal controls from similar socio-economic-geographical background. The expression of HSP70 at mRNA levels was determined by Real Time PCR and at protein levels by indirect Elisa and Western Blot techniques.

Results

We found a significantly higher expression of HSP70 gene expression (approximately 6.45 fold, P < 0.0001) in hypertensive patients as compared to healthy controls. A significant difference (P < 0.0001) in the protein expression of HSP70 was also observed in plasma of patients as compared to that of controls.

Conclusion

Higher expression of HSP70 is positively correlated with inflammatory markers in patients with essential hypertension and this correlation could play an important role in essential hypertension.     

Synthesis and evaluation of Ciprofloxacin derivatives as diagnostic tools for bacterial infection by Staphylococcus aureus

Development of target-specific diagnostic radiopharmaceuticals has always been a challenging task. For this purpose, design and development of the imaging-friendly variant of a potent antibiotic could aid in treatment planning and follow-up of patients with hard-to-diagnose bacterial infections. Fluoroquinolone analogues were synthesized taking the lead from Ciprofloxacin (the broad spectrum antibiotic) molecule. The idea of modifying fluoroquinolones, and subsequently labeling them, was to preserve their capacity to bind bacteria and thereby enable the compound to specifically target those microorganisms. Three compounds were thus synthesized as derivatives of Ciprofloxacin. The fluoroquinolone analogues were labeled with (99m)Tc by using (99m)Tc pertechnetate with high labeling efficiency for all the formulations. The complexes formed by chelation of (99m)Tc with our synthesized fluoroquinolone analogues showed good in vitro serum stability. The blood clearance study performed in New Zealand White rabbits exhibited a curve indicating the initial fast phase in which radiocomplexed drugs cleared from blood very quickly followed by a slow phase. The in vivo evaluation showed that fluoroquinolone-based radiopharmaceuticals bind to the bacteria present at the site of infection, which results in the retention of the agent at sites of active bacterial infection. The biodistribution data and the scintigrams demonstrated that Staphylococcus aureus bacteria in animal infection models took up the radiopharmaceutical formulations, confirming our hypothesis that (99m)Tc fluoroquinolone derivatives might be useful as diagnostic agents for targeted delivery in bacterial infections.     

Inositol trisphosphate production and amylase secretion in mouse pancreatic acini

Dispersed mouse pancreatic acini prelabelled with (3H)-myoinositol generated (3H)-inositol trisphosphate (3H-IP3), (3H)-IP2 and (3H)-IP1 in response to both cholinergic and cholecystokinin analogues. The generation of (3H)-IP3 was very rapid, reaching a maximal value within 5 seconds following hormone stimulation. Stimulation with 10(-3)M carbachol increased (3H)-IP3 to a value which was 13 times that found in unstimulated acini. These results indicate that the mechanism of stimulus-secretion coupling in mouse pancreatic acini may proceed by a mechanism similar to many other systems, including rat pancreatic acini. This sequence includes hormone-stimulated phosphatidylinositol turnover and Ca2+ mobilization, i.e. secretagogue-stimulated generation of IP3 which induces the subsequent release of intracellular Ca2+. These observations differ from those recently reported by Hokin-Neaverson and Sadeghian (J. Biol. Chem. 259: 1346, 1984), in which no hormone stimulated IP3 generation was detected in mouse pancreatic acini.