Mathematical approach for understanding deagglomeration behaviour of drug powder in formulations with coarse carrier

Deagglomeration of cohesive particles in combination with coarse carrier is a key requirement for inhaled formulations. The aim of the project was to propose a mathematical approach to understand aerosolization behaviour of micronized particles alone and in formulation with carriers. Salbutamol sulphate and salmeterol xinafoate were blended separately with fine lactose (ratio 1:4) and fine and coarse lactose (1:4:63.5). Laser diffraction was employed to characterize the powder median particle size. The deagglomeration of micronized materials followed an asymptotic monoexponential relationship. When the coarse lactose was added, the relationship fitted a bi-exponential equation showing an easily and a poorly dispersed fraction. Using model hydrophobic and hydrophilic APIs, this study has demonstrated the utility of an analytical approach that can parameterize deagglomeration behaviour of carrier-free and carrier-based inhalation formulations. The analytical approach provides the ability to systematically study the effect of material, formulation and processing factors on deagglomeration behaviour.     

Characterising surface energy of pharmaceutical powders by inverse gas chromatography at finite dilution

Objectives The objectives of this project were the use of surface energy distributions in: distinguishing the effects of magnesium stearate on the surface energy of lactose processed by two methods: mixing in a Turbula and mechanofusion; characterising surface energy of materials before and after micronisation; and understanding surface energy changes of micronised lactose before and after storage at high relative humidity (RH). Methods Heptane, octane and nonane were used to determine nonpolar surface energy, and dichloromethane and ethyl acetate were used to determine polar surface energy in inverse gas chromatography at finite dilution. Key findings The total surface energy of lactose decreased more after mechanofusion with magnesium stearate than mixing in Turbula. The nonpolar surface energy of indometacin increased while polar and total surface energies decreased after micronisation. The nonpolar, polar and total surface energies and work of cohesion of micronised lactose decreased after storage at 75%RH for three months. Conclusions The surface energy distributions determined at finite dilution successfully distinguished and revealed more information than infinite dilution on surface energy changes in materials undergoing different pharmaceutical processes such as mixing, mechanofusion, micronisation and storage at high RH.     

Influence of storage relative humidity on the dispersion of salmeterol xinafoate powders for inhalation

The in vitro dispersion of salmeterol xinafoate (SX) alone and four SX (2.5%)-coarse lactose (CL) mixtures containing 0%, 5%, 10% and 20% micronised lactose (ML) was monitored during 18-month storage at 33%, 55% and 75% relative humidity (RH) using a twin stage impinger. The surface moisture was monitored over 2 months by thermo gravimetric analysis. The morphology was determined by scanning electron microscopy. An aerosizer was used to compare the agglomerate strengths of formulations before and after storage at 75% RH. Upon storage, no significant difference occurred in fine particle fraction (FPF) of any formulation at 33% and 55% RH. Within 8 weeks, the FPF of mixture containing 20% ML (M20F) significantly decreased from 11.3% to 7.7% at 75% RH (p = 0.008) and to 4.9% at 95% RH (p = 0.001). The calculated capillary forces were greater for ML-ML contact than other particle interactions and the propensity of ML-ML contacts was higher in M20F. The agglomerate strength of M20F significantly increased after storage. The study concluded that the critical factors for decreased dispersion of SX formulations were RH of 75% or greater and the presence of high concentrations of ML due to capillary forces and/or solid bridge formation of ML leading to increased agglomerate strength.     

Lactose Surface Modification by Decantation: Are Drug-Fine Lactose Ratios the Key to Better Dispersion of Salmeterol Xinafoate from Lactose-Interactive Mixtures?

PURPOSE: The role of fine lactose in the dispersion of salmeterol xinafoate (SX) from lactose mixtures was studied by modifying the fine lactose concentration on the surface of the lactose carriers using wet decantation. METHODS: Fine lactose was removed from lactose carriers by wet decantation using ethanol saturated with lactose. Particle sizing was achieved by laser diffraction. Fine particle fractions (FPFs) were determined by Twin Stage Impinger using a 2.5% SX mixture, and SX was analyzed by a validated high-performance liquid chromatography method. Adhesion forces between probes of SX and silica and the lactose surfaces were determined by atomic force microscopy. RESULTS: FPFs of SX were related to fine lactose concentration in the mixture for inhalation grade lactose samples. Reductions in FPF (2-tp 4-fold) of Aeroflo 95 and 65 were observed after removing fine lactose by wet decantation; FPFs reverted to original values after addition of micronized lactose to decanted mixtures. FPFs of SX of sieved and decanted fractions of Aeroflo carriers were significantly different (p < 0.001). The relationship between FPF and fine lactose concentration was linear. Decanted lactose demonstrated surface modification through increased SX-lactose adhesion forces; however, any surface modification other than removal of fine lactose only slightly influenced FPF. CONCLUSIONS: Fine lactose played a key and dominating role in controlling FPF. SX to fine lactose ratios influenced dispersion of SX with maximum dispersion occurring as the ratio approached unity.     

Geranylgeranylacetone protects rat and striatum neurons against heat injury via induction of Hsp70

GGA (geranylgeranylacetone) may induce Hsp70 synthesis, thus contributing to the protective effects of GGA in several disease states. This study evaluated the protective effects of GGA against heat injury to rat and striatum neurons in terms of mechanisms. Rats were exposed to 41.5 °C for 35 min to induce heatstroke; the protective effects of GGA were then evaluated by change in rectal temperature (Tre) during heat exposure and survival time after heatstroke. Primary cultured striatum neurons were incubated with GGA for 24 h, and then heat-treated at 43 °C for a further 1 h. The viability, membrane surface ultrastructure and Hsp70 expression of striatum neurons were all observed. Furthermore, the effects of quercetin an inhibitor of Hsp70 synthesis were also investigated. Compared to the heatstroke group, GGA delayed Tre in reaching 42.1 °C (P < 0.05) and prolonged the survival time after heatstroke (P < 0.01). The LDH releasing percentage decreased in GGA groups (P < 0.05, P < 0.01) compared to the heat-treatment group and increased in quercetin groups (P < 0.05) compared to GGA group. Results from AFM showed that GGA protected membrane surface ultrastructure against heat injury. In addition, results from Western blot showed that GGA-induced Hsp70 expression of neurons both in normal and heat-treatment conditions (P < 0.01, P < 0.05) and quercetin inhibited GGA-induced Hsp70 expression (P < 0.05). Therefore, GGA had protective effects against heat injury in striatum neurons and rat heatstroke. Quercetin inhibited GGA-induced Hsp70 expression and prevented GGA-protective effects, which indicated that this protection was dependent on the Hsp70 synthesis.     

An Investigation into the Rheology of Pharmaceutical Inter-granular Material Bridges at High Shear Rates

Purpose  This study was undertaken to investigate the rheological properties of inter-granular material bridges on the nano-scale when strained at high shear rates. Materials and Methods  Atomic force microscopy (AFM) was used as a rheometer to measure the viscoelasticity of inter-granular material bridges for lactose:PVP K29/32 and lactose:PVP K90 granules, produced by wet granulation. Results  The loss tangent (tan δ) and both the storage (G′) and loss shear moduli (G″) of inter-granular material bridges were measured as a function of the probe–sample separation distance, oscillation frequency and relative humidity (RH). As the probe was withdrawn from the granule surface tan δ initially increased rapidly from zero to a plateau phase. G″ became increasingly dominant as the bridge was further extended and eventually exceeded G′. At high RH, capillary forces were foremost at bridge rupture, whereas at low RH elastic forces dominated. The effect of increasing frequency was to increase the effective elasticity of the bridge at high RH. Conclusions  AFM has been employed as a rheometer to investigate the nano-scale rheology of inter-granular material bridges. This novel method may be used to obtain a fundamental understanding how different binders, granulated with different diluent fillers, behave at high shear rates.     

Surface characterization of salmeterol xinafoate powders by inverse gas chromatography at finite coverage

In our previous studies, surface analysis by inverse gas chromatography (IGC) at infinite dilution (zero coverage) was performed on four salmeterol xinafoate (SX) powdered samples, viz, two supercritical CO2-processed Form I (SX-I) and Form II (SX-II) polymorphs, a commercial granulated SX (GSX) raw material and its micronized product (MSX). Both GSX and MSX are also of the same Form I polymorph. To further probe the differences in surface properties between the samples, the present study has extended the IGC analysis to the finite concentration range of selected energy probes. The adsorption isotherms of the SX samples were constructed using (nonpolar) octane, (polar acidic) chloroform, and (polar basic) tetrahydrofuran as liquid probes. Type II adsorption isotherms with weak knees were observed with each probe for all SX Form I samples. The extents of probe adsorption by the samples at various relative pressures follow the rank order: SX-II > GSX approximately MSX > SX-I, indicating that the SX-I has fewer high-energy adsorption sites than GSX and MSX. Type III isotherms were observed for SX-II with the two polar probes, indicative of weak adsorbate-adsorbent interactions. The additional information generated shows that IGC analysis at finite coverage is a valuable complementary tool to that at infinite dilution.     

Effect of carrier size on the dispersion of salmeterol xinafoate from interactive mixtures

The objective of this study was to determine the influence of lactose carrier size on drug dispersion of salmeterol xinafoate (SX) from interactive mixtures. SX dispersion was measured by using the fine particle fractions determined by a twin stage impinger attached to a Rotahaler. The particle size of the lactose carrier in the SX interactive mixtures was varied using a range of commercial inhalation-grade lactoses. In addition, differing size fractions of individual lactose samples were achieved by dry sieving. The dispersion of SX appeared to increase as the particle size of the lactose carrier decreased for the mixtures prepared from different particle size commercial samples of lactose and from different sieve fractions of the same lactose. Fine particles of lactose (<5 microm) associated with the lactose carrier were removed from the carrier surface by a wet decantation process to produce lactose samples with low but similar concentrations of fine lactose particles. The fine particle fractions of SX in mixtures prepared with the decanted lactose decreased significantly (analysis of variance, p < 0.001) and the degree of dispersion became independent of the volume mean diameter of the carriers (analysis of variance, p < 0.05). The dispersion behavior is therefore associated with the presence of fine adhered particles associated with the carriers and the inherent size of the carrier itself has little influence on dispersion.     

A combination of Chinese herbs, Astragalus membranaceus var. mongholicus and Angelica sinensis, improved renal microvascular insufficiency in 5/6 nephrectomized rats

Chronic renal ischemia and hypoxia in the tubulointerstitium are involved in the mechanisms of progressive chronic kidney disease. Previous studies showed that the decoction of a combination of two Chinese herbs, Astragalus membranaceus var. mongholicus and Angelica sinensis (A & A) has antifibrotic effects through multiple pathways in different animal models. In this study, remnant kidney model was employed to investigate whether A & A affect the expression of VEGF, the density of the renal microvasculature and thus alleviate the renal injury. Rats were divided randomly into four groups: sham group (N = 31), 5/6 Nx group (5/6 nephrectomy, N = 43), A & A treated group (A & A group, N = 40, A & A 12 g/kg/d po), enalapril treated group (Ena group, N = 56, enalapril 4 mg/kg/d po). Rats from each group were sacrificed at the 2th, 4th, 8th and 12th weeks respectively after surgery and treatment. The 24 h urinary protein excretion, serum creatinine (Scr) and urea were measured. The collagen IV (COL-IV), fibronectin (FN), aminopeptidase P (APP) and VEGF were stained using immunohistochemistry. The COL-IV, FN and APP were semi-quantitatively analyzed. Peritubular capillary density in the cortical interstitial area was quantified. The level of VEGF was assayed by ELISA. The results revealed that Scr, urea and urinary protein excretion remained constant at each time point in sham group. Compared to sham group, 5/6 Nx group was shown severe glomerulosclerosis, tubulointerstitial lesions and vascular damage, as well as higher level of Scr from the 2nd week (72.3 ± 5.2 vs. 48.6 ± 2.6 μmol/L, P < 0.05) to the 12th week (71.9 ± 8.0 vs. 55.7 ± 4.5 μmol/L, P < 0.05). Although there was no significant difference in Scr level after treatment of enalapril or A & A (P > 0.05), kidney damage was alleviated at the 8th and the 12th week in the two treatment groups (P < 0.05, vs. 5/6 Nx group). The urinary protein excretion of 5/6 Nx group was significantly increased from the 4th week, it was 1.5, 2.4 and 3.8 fold of that of sham group at the 4th, 8th and 12th week, respectively. Compared to 5/6 Nx group, proteinuria was decreased by enalapril to 59%, 33% at 8th and 12th week. After A & A administration, urinary protein excretion decreased to 66%, 56%, 75%, 55% of 5/6 Nx group at the 2nd, 4th, 8th and 12th, respectively (P < 0.05). Compared with sham group, there was increased expression of FN and COL-IV in rats with 5/6 Nx. After A & A or enalapril administration, the expression of FN and COL-IV was significantly decreased compared with that in the 5/6 Nx group at 8th and 12th week (P < 0.05). On the other hand, the capillary density was decreased at the 8th and 12th week in 5/6 Nx rats (P < 0.01). In A & A-treated group, similarly with enalapril group, the amount of APP-positive glomerular capillary increased by 36% (P < 0.01), and the peritubular capillary density was increased 94% at 8th week and 52% at 12th week compared with 5/6 Nx group (P < 0.05). The renal level of VEGF was decreased in 5/6 Nx rats, but increased at the 8th and 12th week in A & A group (P < 0.05, vs. 5/6 Nx group). In conclusion, A & A has renoprotective effects by suppression of extra cellular matrix deposition in 5/6 Nx rat. The renoprotective effects may be associated with reduction of proteinuria, up-regulation of VEGF which may reduce the loss of capillaries and improve microstructure dysfunction.     

Dry powder formulations for inhalation of fluticasone propionate and salmeterol xinafoate microcrystals

Direct crystallization of active pharmaceutical ingredient (API) particles in the inhalable size range of 1-6 microm may overcome surface energization resulting from micronization. The aerosolization of fluticasone propionate (FP) and salmeterol xinafoate (SX) microcrystals produced by aqueous crystallization from poly(ethylene glycol) solutions was investigated using a twin stage impinger following blending with lactose. Fine particle fractions from SX formulations ranged from 15.98 +/- 2.20% from SX crystallized from PEG 6000 to 26.26 +/- 1.51% for SX crystallized from PEG 400. The FPF of microcrystal formulations increased as the particle size of microcrystals was increased. The aerosolization of SX from DPI blends was equivalent for the microcrystals and the micronized material. FP microcrystals, which had a needlelike morphology, produced similar FPFs (PEG 400: 17.15 +/- 0.68% and PEG 6000: 15.46 +/- 0.97%) to micronized FP (mFP; 14.21 +/- 0.54). The highest FPF (25.66 +/- 1.51%) resulted from the formulation of FP microcrystals with the largest median diameter (FP PEG 400B: 6.14 +/- 0.17 microm). Microcrystallization of SX and FP from PEG solvents offers the potential for improving control of particulate solid state properties and was shown to represent a viable alternative to micronization for the production of particles for inclusion in dry powder inhalation formulations.     

Comparative evaluation of the hypolipidemic effects of coconut water and lovastatin in rats fed fat–cholesterol enriched diet

The coconut water presents a series of nutritional and therapeutic properties, being a natural, acid and sterile solution, which contains several biologically active components, l-arginine, ascorbic acid, minerals such as calcium, magnesium and potassium, which have beneficial effects on lipid levels. Recent studies in our laboratory showed that both tender and mature coconut water feeding significantly (P < 0.05) reduced hyperlipidemia in cholesterol fed rats [Sandhya, V.G., Rajamohan, T., 2006. Beneficial effects of coconut water feeding on lipid metabolism in cholesterol fed rats. J. Med. Food 9, 400–407]. The current study evaluated the hypolipidemic effect of coconut water (4 ml/100 g body weight) with a lipid lowering drug, lovastatin (0.1/100 g diet) in rats fed fat–cholesterol enriched diet ad libitum for 45 days. Coconut water or lovastatin supplementation lowered the levels of serum total cholesterol, VLDL + LDL cholesterol, triglycerides and increased HDL cholesterol in experimental rats (P < 0.05). Coconut water feeding decreased activities of hepatic lipogenic enzymes and increased HMG CoA reductase and lipoprotein lipase activity (P < 0.05). Incorporation of radioactive acetate into free and ester cholesterol in the liver were higher in coconut water treated rats. Coconut water supplementation increased hepatic bile acid and fecal bile acids and neutral sterols (P < 0.05). Coconut water has lipid lowering effect similar to the drug lovastatin in rats fed fat–cholesterol enriched diet.     

The influence of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its metabolite—dichlorodiphenyldichloroethylene (DDE) on mRNA expression for NP-I/OT and PGA, involved in oxytocin synthesis in bovine granulosa and luteal cells

The effect of polychlorinated biphenyls (PCBs) congeners (PCB 77, PCB 126, PCB 153) and their technical mixture—Aroclor (Ar) 1248, as well as dichlorodiphenyltrichloroethane (DDT) and its metabolite—dichlorodiphenyldichloroethylene (DDE; two individual isomers p,p′- and o,p′- or their mixture, 95% and 5%, respectively) at the dose of 10 ng/ml each, on the gene expression of (a) oxytocin (OT) precursor—neurophysin–oxytocin (NP-I/OT) and (b) peptidyl glycine-α-amidating mono-oxygenase (PGA), the terminal enzyme in the pathway of OT synthesis, was studied. Granulosa cells from follicles >1 cm in diameter, collected on days 19–21 of estrous cycle, and luteal cells from corpora lutea (CL) collected on days 8–12 of the estrous cycle were used. The cells were incubated (6 h) with these xenobiotics and the expression of NP-I/OT and PGA genes was determined. All PCBs increased (P < 0.05) NP-I/OT gene expression in granulosa cells. Similarly, all PCBs but PCB 126 increased (P < 0.05) PGA gene expression in these cells. DDT and DDE increased (P < 0.05) gene expression of NP-I/OT in granulosa cells, while gene expression of PGA in these cells was stimulated (P < 0.05) by DDE only. The mRNA expression for NP-I/OT and PGA in luteal cells was increased (P < 0.05) by PCB 77 and PCB 153. Both DDE isomers and mixture also stimulated (P < 0.05) of NP-I/OT mRNA expression, while increase (P < 0.05) of PGA mRNA expression was elicited by incubation of these cells with DDE mixture and Ar 1248.Obtained data suggest that PCBs, DDT and DDE can affect the mRNA expression for NP-I/OT and PGA in bovine granulosa and luteal cells.     

The improvement of exercise performance by physical training is related to increased hypothalamic neuronal activation

The effects of physical training on hypothalamic activation after exercise and their relationship with heat dissipation were investigated. Following 8 weeks of physical training, trained (TR, n = 9) and untrained (UN, n = 8) Wistar rats were submitted to a regimen of incremental running until fatigue while body and tail temperatures were recorded. After exercise, hypothalamic c‐Fos immunohistochemistry analysis was performed. The workload, body‐heating rate, heat storage and body temperature threshold for cutaneous vasodilation were calculated. Physical training increased the number of c‐Fos immunoreactive neurons in the paraventricular, medial preoptic and median preoptic nucleus by 112%, 90% and 65% (P < 0.01) after exercise, respectively. In these hypothalamic regions, increased neuronal activation was directly associated with the increased workload performed by TR animals (P < 0.01). Moreover, a reduction of 0.6°C in the body temperature threshold for cutaneous vasodilation was shown by TR animals (P < 0.01). This reduction was possibly responsible for the lower body‐heating rate (0.019 ± 0.002°C/min, TR vs 0.030 ± 0.005°C/min, UN, P < 0.05) and the decreased ratio between heat storage and the workload performed by TR animals (18.18 ± 1.65 cal/kg, TR vs 31.38 ± 5.35 cal/kg, UN, P < 0.05). The data indicate that physical training enhances hypothalamic neuronal activation during exercise. This enhancement is the central adaptation relating to better physical performance, characterized by a lower ratio of heat stored to workload performed, due to improved heat dissipation.     

Dry powder inhaler: influence of humidity on topology and adhesion studied by AFM.

In the dry powder inhalers (DPIs), the adhesion results of the interactions between the active substance and the excipient. The carrier and the micronized drug particle morphologies are believed to affect the delivery of the drug. In this work, the couple studied was the lactose monohydrate and micronized zanamivir, used for the treatment of influenza. In a first approach, observations by scanning electron microscopy (SEM) have shown that the relative humidity (RH) greatly influenced the zanamivir amount fixed on the lactose monohydrate surface. This paper deals with the direct measurement in controlled atmosphere by atomic force microscopy (AFM) of the forces and the interaction ranges between a zanamivir probe and a lactose substrate. Selected zanamivir crystals were attached to the standard AFM probe. Different RH have been used in order to determine influent parameters permitting to identify the nature of adhesion forces between them. This study demonstrated that the increase of RH modified progressively the surface topology of the two components and increased the adhesion force.     

Agglomerate Strength and Dispersion of Salmeterol Xinafoate from Powder Mixtures for Inhalation

Purpose The study investigated the role of agglomeration and the effect of fine lactose size on the dispersion of salmeterol xinafoate (SX) from SX–lactose mixtures for inhalation.Methods Particle size distributions were characterised by Malvern Mastersizer S, Aerosizer and Spraytec, and imaging conducted by scanning electron microscopy (SEM). Inter-particulate adhesion was quantified by atomic force microscopy. Deposition of SX was measured using a twin stage impinger. SX was analysed using validated high-performance liquid chromatography method (r ²=1.0, CV=0.4–1.0%).Results Addition of fine lactose with a volume median diameter (VMD) of 7.9 μm to a SX–lactose carrier and carrier-free mixture resulted in significantly better dispersion (16.8% for 20% added fine lactose) than fractions with VMD of 3.0, 17.7 and 33.3 μm (less than 9.1% for 20% fine lactose). Using the carrier-free mixtures, particle sizing of the aerosol cloud using the Spraytec, coupled with the application of the Aerosizer using differing dispersion energies and SEMs of the samples, indicated that an open packed, agglomerate structure improved SX dispersion. The highest extent of SX dispersion occurred when SX and fine lactose were detached from the surface, usually in the form of loose agglomerates.Conclusions The outcomes of this research demonstrated how agglomerate structure influenced dispersion and the key role of fine lactose particle size in SX dispersion from mixtures for inhalation.     

Following the surface response of caffeine cocrystals to controlled humidity storage by atomic force microscopy

Active pharmaceutical ingredient (API) stability in solid state tablet formulation is frequently a function of the relative humidity (RH) environment in which the drug is stored. Caffeine is one such problematic API. Previously reported caffeine cocrystals, however, were found to offer increased resistance to caffeine hydrate formation. Here we report on the use of atomic force microscopy (AFM) to image the surface of two caffeine cocrystal systems to look for differences between the surface and bulk response of the cocrystal to storage in controlled humidity environments. Bulk responses have previously been assessed by powder X-ray diffraction. With AFM, pinning sites were identified at step edges on caffeine/oxalic acid, with these sites leading to non-uniform step movement on going from ambient to 0% RH. At RH >75%, areas of fresh crystal growth were seen on the cocrystal surface. In the case of caffeine/malonic acid the cocrystals were observed to absorb water anisotropically after storage at 75% RH for 2 days, affecting the surface topography of the cocrystal. These results show that AFM expands on the data gathered by bulk analytical techniques, such as powder X-ray diffraction, by providing localised surface information. This surface information may be important for better predicting API stability in isolation and at a solid state API–excipient interface.     

Adhesion and redistribution of salmeterol xinafoate particles in sugar-based mixtures for inhalation

The aim of this study was to evaluate coarse and fine sugars as potential alternative excipients in dry powder inhalation formulations and to develop a greater understanding of the key interactions between the particulate species in these mixtures. Interactive mixtures composed of salmeterol xinafoate (SX) and different type of sugars (lactose, glucose, mannitol and sorbitol) were prepared using validated laboratory scale mixing. The sugars and SX were characterised by laser diffraction, scanning electron microscopy, atomic force microscopy and loss on drying method. Deposition of SX was measured using a twin-stage impinger and analysed using validated HPLC method (r(2)=1.0, CV=0.4-1.0%). Good correlation existed between the fine particle fraction (FPF) of SX and both the adhesion force and the moisture content. The addition of 10% fine sugars to produce ternary mixtures (i.e. SX, coarse and fine sugars) generally increased dispersion, with the addition of fine glucose>fine mannitol>fine lactose>fine sorbitol. The dispersion of SX showed a reciprocal relationship with the moisture content of the sugars with glucose showing the greatest and sorbitol showing the lowest extent of SX dispersion. The study clearly demonstrated that strong SX adhesion to coarse sugars reduced the extent of dispersion and that surface detachment of the SX and fine sugar from the coarse sugar carrier was important in the dispersion process.     

Effects of Tityus serrulatus scorpion venom on lung mechanics and inflammation in mice

The present study evaluated the effects of an intramuscular injection of Tityus serrulatus venom (TsV) (0.67 μg/g) on lung mechanics and lung inflammation at 15, 30, 60 and 180 min after inoculation. TsV inoculation resulted in increased lung elastance when compared with the control group (p < 0.001); these values were significantly higher at 60 min than at 15 and 180 min (p < 0.05). Resistive pressure (ΔP₁) values decreased significantly at 30, 60 and 180 min after TsV injection (p < 0.001). TsV inoculation resulted in increased lung inflammation, characterised by an increased density of mononuclear cells at 15, 30, 60 and 180 min after TsV injection when compared with the control group (p < 0.001). TsV inoculation also resulted in an increased pulmonary density of polymorphonuclear cells at 15, 30 and 60 min following injection when compared to the control group (p < 0.001). In conclusion, T. serrulatus venom leads to acute lung injury, characterised by altered lung mechanics and increased pulmonary inflammation.     

Investigations on the Mechanism of Magnesium Stearate to Modify Aerosol Performance in Dry Powder Inhaled Formulations

The potential of the force control agent magnesium stearate (MgSt) to enhance the aerosol performance of lactose-based dry powder inhaled (DPI) formulations was investigated in this study. The excipient-blends were investigated with analytical techniques including time-of-flight secondary ion mass spectrometry and single particle aerosol mass spectrometry (SPAMS), and particle size, morphology, and surface properties were evaluated. Excipient-blends were manufactured either by high-shear or low-shear blending lactose carrier with different amounts of MgSt in the range from 0% to 10% (w/w). Fluticasone propionate (FP) and salmeterol xinafoate (SX) used as model active pharmaceutical ingredients were added by low-shear mixing. The in vitro aerosol performance in terms of aerodynamic particle size distribution and fine particle fraction (FPF) of the FP and SX DPI formulations was evaluated with the Next Generation Impactor and also with SPAMS using a Breezhaler^® inhalation device. The distribution of MgSt on the lactose carrier in the blends was visualized and found to depend strongly on the blending method. This affected drug particle detachment from the carrier and thus impacted aerosol performance for FP and SX. Compared with blends without force control agent, low-shear blending of MgSt increases the FPF of the model drug SX, whereas high-shear blending significantly increased FPF of both SX and FP. The interactions between drug and carrier particles were substantially affected by the choice of blending technique of MgSt with lactose. This allows detailed control of aerosol performance of a DPI by an adequate choice of the blending technique. SPAMS successfully demonstrated that it is capable to distinguish changes in DPI formulations blended with different amounts of MgSt, and additional information in terms of dispersibility of fine particles could be generated.     

TRK-820, a selective kappa opioid receptor agonist, could effectively ameliorate L-DOPA-induced dyskinesia symptoms in a rat model of Parkinson's disease

The objective of the present study was to investigate the effect of the administration of resveratrol (RV) on memory and on acetylcholinesterase (AChE) activity in the cerebral cortex, hippocampus, striatum, hypothalamus, cerebellum and blood in streptozotocin-induced diabetic rats. The animals were divided into six groups (n = 6–13): Control/saline; Control/RV 10 mg/kg; Control/RV 20 mg/kg; Diabetic/saline; Diabetic/RV 10 mg/kg; Diabetic/RV 20 mg/kg. One day after 30 days of treatment with resveratrol the animals were submitted to behavioral tests and then submitted to euthanasia and the brain structures and blood were collected. The results showed a decrease in step-down latency in diabetic/saline group. Resveratrol (10 and 20 mg/kg) prevented the impairment of memory induced by diabetes. In the open field test, no significant differences were observed between the groups. In relation to AChE activity, a significant increase in diabetic/saline group (P < 0.05) was observed in all brain structures compared to control/saline group. However, AChE activity decreased significantly in control/RV10 and control/RV20 (P < 0.05) groups in cerebral cortex, hippocampus and striatum, while no significant differences were observed in diabetic/RV10 and diabetic/RV20 groups in all brain structures compared to control/saline group. Blood AChE activity increased significantly in diabetic/saline group (P < 0.05) decreased in control/RV10, control/RV20 and diabetic/RV20 groups (P < 0.05) compared to control/saline group. In conclusion, the present findings showed that treatment with resveratrol prevents the increase in AChE activity and consequently memory impairment in diabetic rats, demonstrating that this compound can modulate cholinergic neurotransmission and consequently improve cognition.