State of insulin self-association does not affect its absorption from the pulmonary route.

This study is designed to compare and contrast the pulmonary absorption profiles of monomeric and hexameric insulin in the presence or absence of ethylene diamine tetraacetic acid (EDTA) or n-tetradecyl-beta-d-maltoside (TDM). The pulmonary absorption of two forms of insulin was studied by monitoring the changes in plasma insulin and glucose levels after intratracheal administration of monomeric or hexameric insulin into anesthetized rodents. EDTA or TDM was added to the formulation in order to evaluate if either of these agents has effects on the rate and extent of pulmonary absorption of monomeric and hexameric insulin. The biochemical changes that may occur after acute administration of TDM-based formulation have also been investigated by estimating lung injury markers in bronchoalveolar lavage fluid. A dose-dependent increase in the plasma insulin and decrease in plasma glucose levels was observed when increasing concentrations of hexameric or monomeric insulin were administered via the pulmonary route. Pulmonary administration of monomeric and hexameric insulin produced comparable absorption profiles in the presence or absence of EDTA or TDM. The bronchoalveolar lavage fluid analysis did not show differences in the levels of injury markers produced in TDM-treated rats and that produced in saline-treated rats, indicating no evidence for adverse effects of TDM in these short-term studies. Overall, in terms of rapidity of action and efficacy to reduce blood sugar, monomeric insulin did not provide advantages over hexameric insulin when administered via the pulmonary route.     

Inhaled Insulin is Better Absorbed When Administered as a Dry Powder Compared to Solution in the Presence or Absence of Alkylglycosides

Purpose This study was performed to investigate the safety of alkylglycosides administered via the respiratory route and to compare the pulmonary absorption profiles of insulin administered as dry powder inhaler and inhaler solution. Methods The safety of a series of alkylglycosides with varying alkyl chain lengths was studied by measuring the enzymatic activities in the bronchoalveolar lavage (BAL) fluid of rat lungs. Pulmonary formulations of insulin plus octylmaltoside were administered either as solution or lyophilized dry powder to anesthetized rats, and absorption of insulin was assessed by measuring plasma insulin and glucose levels. The physical characterization of the dry powder formulation was performed using scanning electron microscope (SEM) and Fourier transform infrared spectrophotometer (FTIR). Results The BAL analysis showed that there was a gradual increase in the amount of lung injury markers released with the increase in the hydrophobic chain length of alkylglycosides. The pulmonary administration of lyophilized dry powder of insulin plus octylmaltoside or its solution counterpart showed that the bioavailability of powder formulation was about 2-fold higher than that of the formulation administered as solution. The SEM studies showed a subtle difference in the surface morphologies of formulation particles after lyophilization. FTIR data showed minor interactions between the peptide and excipients upon lyophilization. Conclusions Of the alkylglycosides tested, octylmaltoside was least toxic in releasing lung injury markers. Octylmaltoside-based dry powder insulin formulations were more efficacious in enhancing pulmonary insulin absorption and reducing plasma glucose levels compared with the formulations administered as a solution.     

Phospholipid concentration in lung lavage fluid as biomarker for pulmonary fibrosis

Pulmonary surfactant comprised primarily of phospholipids is a phospholipid-protein complex synthesized by type II alveolar epithelial cells or Clara cells and secreted to the pulmonary alveoli. As changes have been found in phospholipid concentrations in the bronchoalveolar lavage fluid (BALF) of patients with pulmonary fibrosis, phospholipid is considered to be involved in the process of fibrois/fibrotic process. Therefore, we made a crystalline silica rat model and measured phospholipid concentrations in lung lavage fluid in order to study the relationship of phospholipid to particle-induced pulmonary fibrosis. Eight-week-old Wistar male rats (n = 35) were injected with 2 mg crystalline silica particles suspended in 0.4 ml physiological saline. Rats in the control group (n = 35) were injected with physiological saline only. There were 7 rats in each of the ten subgroups. Rats were sacrificed and dissected at 3 days, 1 wk, 1 mo, 3 mo, and 6 mo after injection. Bronchoalveolar lavage was conducted on bronchoalveoli recovered from the right lung of each rat, the lavage fluid was centrifuged, and the supernatant was used to measure phospholipid concentration. The results were compared with previously reported inflammation scores. Phospholipid concentrations in lung lavage fluid for the exposed group showed a statistically significant increase compared to the control group throughout the observation period. Moreover, when compared to histopathologically examined inflammation scores, a positive correlation was found between the two. Judging from the facts that phospholipid concentrations in lung lavage fluid increased and that this increase correlated with the severity of inflammation, this experiment indicated that phospholipids are involved in particle-induced lung disorders.     

Phospholipid Concentration in Lung Lavage Fluid as Biomarker for Pulmonary Fibrosis

Pulmonary surfactant comprised primarily of phospholipids is a phospholipid-protein complex synthesized by type II alveolar epithelial cells or Clara cells and secreted to the pulmonary alveoli. As changes have been found in phospholipid concentrations in the bronchoalveolar lavage fluid (BALF) of patients with pulmonary fibrosis, phospholipid is considered to be involved in the process of fibrois/fibrotic process. Therefore, we made a crystalline silica rat model and measured phospholipid concentrations in lung lavage fluid in order to study the relationship of phospholipid to particle-induced pulmonary fibrosis. Eight-week-old Wistar male rats (n = 35) were injected with 2 mg crystalline silica particles suspended in 0.4 ml physiological saline. Rats in the control group (n = 35) were injected with physiological saline only. There were 7 rats in each of the ten subgroups. Rats were sacrificed and dissected at 3 days, 1 wk, 1 mo, 3 mo, and 6 mo after injection. Bronchoalveolar lavage was conducted on bronchoalveoli recovered from the right lung of each rat, the lavage fluid was centrifuged, and the supernatant was used to measure phospholipid concentration. The results were compared with previously reported inflammation scores. Phospholipid concentrations in lung lavage fluid for the exposed group showed a statistically significant increase compared to the control group throughout the observation period. Moreover, when compared to histopathologically examined inflammation scores, a positive correlation was found between the two. Judging from the facts that phospholipid concentrations in lung lavage fluid increased and that this increase correlated with the severity of inflammation, this experiment indicated that phospholipids are involved in particle-induced lung disorders.     

Airway inflammatory events in diabetic-antigen sensitized guinea pigs

Experimental evidence indicates that the relative lack of insulin in an organism results in an overall reduction in inflammatory reactions. This study was planned to determine the inflammatory events in antigen sensitized diabetic guinea pigs. Twenty-five male guinea pigs were categorized into five groups of five each as follows: diabetic, antigen sensitized, antigen sensitized diabetic, insulin-treated antigen sensitized diabetic and control animals. Induction of experimental diabetes and antigen sensitization was performed by injection of streptozotocin and ovalbumin, respectively. Animals were killed by exsanguination and bronchoalveolar lavage was performed. Bronchoalveolar lavage fluid cellular and protein contents were determined. Airway responsiveness to acetylcholine was assessed using isolated tracheal triple-ring. Histopathological examinations were performed on the lungs. Decreases in the airway reactivity in diabetic and antigen sensitized diabetic animals were found compared with antigen sensitized animals. Experimental diabetes also decreased antigen-induced protein leakage into the airspace as well as the accumulation of inflammatory cells (eosinophils, neutrophils, lymphocytes and macrophages) in bronchoalveolar lavage fluid of antigen sensitized animals. Insulin treatment prevented these decreases in protein content and inflammatory cells infiltration in bronchoalveolar lavage fluid observed in the antigen sensitized guinea pigs with diabetes. Histopathological results showed that coinduction of experimental diabetes significantly reduces the number of eosinophils in the lungs of antigen sensitized animals. Again, treatment with insulin increased the number of eosinophils in the antigen sensitized diabetic animals. Experimental diabetes causes were found to decrease the airway reactivity and inflammatory responsiveness induced by antigen sensitization due to a reduction in the insulin levels.     

Polyamidoamine dendrimers can improve the pulmonary absorption of insulin and calcitonin in rats

The absorption-enhancing effects of polyamidoamine (PAMAM) dendrimers with various generations (G0-G3) and concentrations [0.1%-1.0% (w/v)] on the pulmonary absorption of peptide and protein drugs were studied in rats. Insulin and calcitonin were chosen as models of peptide and protein drugs, and their pulmonary absorption with or without PAMAM dendrimers was examined by in vivo pulmonary absorption studies. PAMAM dendrimers significantly increased the pulmonary absorption of insulin and calcitonin in rats, and their absorption-enhancing effects were generation dependent. The rank order of absorption enhancement effect of these PAMAM dendrimers was G3 > G2 > G1 > G0. For the same generation, the absorption-enhancing effects of PAMAM dendrimers were shown to be concentration dependent. The toxicity of these PAMAM dendrimers in the lung tissues was evaluated by measuring the release of protein and the activities of lactate dehydrogenase (LDH) in bronchoalveolar lavage fluid (BALF). The PAMAM dendrimers with various generations and concentrations did not significantly increase the release of protein and the activities of LDH in BALF, indicating that these dendrimers did not cause any membrane damage to the lung tissues. The zeta potentials of insulin and calcitonin solutions changed to positive by the addition of PAMAM dendrimers, and the degree of positive charge as determined by the zeta potentials was linearly correlated with the absorption-enhancing effects of the PAMAM dendrimers. This positive charge of the PAMAM dendrimers might be related to their absorption-enhancing mechanisms for improving the pulmonary absorption of insulin and calcitonin in rats. In conclusion, the PAMAM dendrimers are suitable absorption enhancers to improve the pulmonary absorption of insulin and calcitonin without any membrane damage to the respiratory tissues.     

The effect of hexafluorocyclobutene on rat bronchoalveolar lavage fluid surfactant phospholipids and alveolar type II cells

Hexafluorocyclobutene (HFCB), a reactive organohalogen gas, causes overwhelming pulmonary oedema. We investigated its effect on the rat lung surfactant system, comparing its action on type II pneumocytes with air-exposed rats. The inflammatory cell population and protein content of bronchoalveolar lavage fluid was analysed following exposure to air or HFCB (LCt30). Six rat lung phospholipids were measured by high-performance liquid chromatography, following solid phase extraction (SPE) from lavage fluid. Transmission electron microscopy (TEM) was used to visualise effects on alveolar type II cell ultrastructure. HFCB caused changes in cell populations and increased lavage fluid protein compared to controls, suggesting a permeability oedema. Changes in the total amount and percentage composition (sustained decrease in phosphatidylglycerol and phosphatidylcholine) of surfactant phospholipids also occurred. TEM observations indicated no direct ultrastructural damage to the type II cells, but showed initial, rapid release of surfactant into the alveolar space. HFCB altered the surfactant system in a manner similar to that shown following another reactive organohalogen gas, perfluoroisobutene (PFIB), but differently to that after phosgene. These differences suggest different mechanisms of action even though pulmonary oedema is the final injury for all gases. Better knowledge of the mechanisms involved will improve prospects for prophylactic/therapeutic intervention.     

Studies on the liberation behavior of insulin from polymeric matrices

The in-vitro and in-vivo liberation of insulin from embeddings in polymeric matrices was investigated dependent on the charging degree, the particle- and pore size, respectively, of the granules and the dissolution behaviour of the hormone. Polyacrylamide, agar-agar, dextrane and Sephadex G-100 were used as ground-mass. These polymers are characterized by a good swelling and a high binding capacity. If these properties quality them for insulin was investigated in model experiments. Information concerning the obtained retention effects of the matrix mould were produced by photochemical methods (application of insulin against citrate phosphate buffer; absorption region of 230 to 320 nm). The in-vitro effects yielded could be confirmed by means of representative in-vivo studies in eumetabolic insulin sensitive rabbits.     

The effect of in-vivo dispersion and gastric emptying on glibenclamide absorption from a novel, rapidly dissolving capsule formulation

The in-vivo dispersion and gastric emptying of a novel glibenclamide dose form have been investigated using gamma-scintigraphy and related to the absorption of glibenclamide determined by measuring glibenclamide plasma concentrations. Its absorption is determined by the rate of emptying of the dose form from the stomach with the lag time between dosing and the start of gastric emptying (and hence absorption of the dose) largely dependent on the in-vivo disintegration time. The presence of food in the stomach has a marked effect on in-vivo disintegration/dispersion of the dose form and hence on the lag time between dosing and the start of absorption.     

金舒喜辅助治疗子宫颈CINⅠ-Ⅲ对阴道微生态及阴道灌洗液IL-10、IFN-γ水平的影响观察

探讨金舒喜辅助治疗宫颈上皮内瘤变(CIN)Ⅰ-Ⅲ对阴道微生态及阴道灌洗液白介素-10(IL-10)、干扰素-γ(IFN-γ)的影响。将该院于2017年8月~2019年3月接诊的76例CIN患者随机均分为研究组及对照组,研究组(38例)给予辛复宁+金舒喜治疗,对照组(38例)仅给予辛复宁治疗,比较两组患者治疗3个月后人乳头瘤病毒(HPV)感染和CIN疗效及阴道微生态、阴道灌洗液IL-10、IFN-γ等情况。研究组HPV感染和CIN疗效均明显优于对照组(P<0.05);两组治疗后白带量、色泽、质地和气味均明显改善(P<0.05),阴道病原体检出率和阴道灌洗液IL-10水平均显著降低(P<0.05),乳酸杆菌检出率、阴道p H<4.5比例和阴道灌洗液IFN-γ水平均显著增加(P<0.05);研究组临床症状、阴道微生态、阴道灌洗液IL-10、IFN-γ水平变化幅度均大于对照组(P<0.05)。金舒喜辅助治疗子宫颈CINⅠ-Ⅲ疗效确切,可有效改善患者阴道微生态,调节阴道内IL-10、IFN-γ水平。     

Biotinylated liposomes as potential carriers for the oral delivery of insulin

This study aimed to explore biotinylated liposomes (BLPs) as novel carriers to enhance the oral delivery of insulin. Biotinylation was achieved by incorporating biotin-conjugated phospholipids into the liposome membranes. A significant hypoglycemic effect and enhanced absorption were observed after treating diabetic rats with the BLPs with a relative bioavailability of 12.09% and 8.23%, based on the measurement of the pharmacologic effect and the blood insulin level, respectively; this achieved bioavailability was approximately double that of conventional liposomes. The significance of the biotinylation was confirmed by the facilitated absorption of the BLPs through receptor-mediated endocytosis, as well as by the improved physical stability of the liposomes. Increased cellular uptake and quick gastrointestinal transport further verified the ability of the BLPs to enhance absorption. These results provide a proof of concept that BLPs can be used as potential carriers for the oral delivery of insulin.From the Clinical EditorDiabetes remains a major source of mortality in the Western world, and advances in its management are expected to have substantial socioeconomic impact. In this paper, biotinylated liposomes were utilized as carriers of insulin for local delivery, demonstrating the feasibility of this approach in a rat model.     

Effects of chronic exposure to ozone on pulmonary lipids in rats

Ozone is the most toxic component of photochemical oxidant air pollution. Exposure to high concentrations of ozone produces a variety of toxic effects in the lung, but it is not known to what extent prolonged exposure to low concentrations of ozone may contribute to the development of chronic lung disease. Phospholipids, important components of cellular membranes and surfactant, are necessary for the maintenance of normal lung structure and function. In order to test the effects of chronic exposure to environmentally relevant concentrations of ozone on phospholipid metabolism in the lung, rats were exposed to clean air or to 0.12, 0.25 or 0.50 ppm ozone for up to 18 months. The content and biosynthesis of phospholipids in both lung tissue and bronchopulmonary lavage fluid (surfactant) were measured. Incorporation of [14C]acetate into lung tissue phospholipids, an estimate of overall biosynthesis, decreased significantly at some time points in the study, while tissue phospholipid content tended to increase with both ozone concentration and with age. No changes were detected in phospholipid content of bronchopulmonary lavage fluid. These findings did not support the hypothesis that prolonged exposure of rats to environmentally relevant concentrations of ozone results in either qualitative or quantitative deficits in the pulmonary surfactant system.     

Evaluation of absorbability of centpropazine in rats: in-situ and in-vivo appraoches.

Intestinal absorption of centpropazine was studied in rats by both in-situ (closed-loop method) and in-vivo (portal-venous difference) approaches. The drug was found to be well absorbed from solution in in-situ studies. However, the results obtained in-vivo suggested that very low amounts of drug reach the portal circulation after oral dosing. This could imply extensive binding to the mucosa or metabolism in the intestinal wall. The presence of higher amounts of metabolites in the portal vein compared with the inferior vena cava samples signal their formation in the gastrointestinal tract or enterohepatic recirculation. These findings will be useful in incorporating suitable structural and formulation modifications for enhancing the bioavailability of centpropazine and its analogues.     

The effect of perfluoroisobutene and phosgene on rat lavage fluid surfactant phospholipids

1. This study investigated whether the reactive organohalogen gases perfluoroisobutene (PFIB) and phosgene, which cause death by overwhelming pulmonary oedema, affect the surfactant system or type II pneumocytes of rat lung. 2. The progression and type of pulmonary injury in Porton Wistar-derived rats was monitored over a 48 h period following exposure to either PFIB or phosgene (LCt30) by analyzing the inflammatory cells and protein in bronchoalveolar lavage fluid. Six rat lung phospholipids were measured by high-performance liquid chromatography, following solid phase extraction from lavage fluid. 3. Alterations in the cell population and lung permeability occurred following both gases, indicating that the injury was a permeability-type pulmonary oedema. Changes in the total amount of phospholipid and in the percentage composition of the surfactant were different for the two gases. PFIB produced increases in phosphatidylglycerol and phosphatidylcholine over the first hour, similar to that seen following air exposure, followed by substantial decreases in these phospholipids. Phosgene caused late increases in all phospholipids from 6 h post-exposure. 4. Differences in the response of the surfactant system to exposure to PFIB and phosgene suggest different mechanisms of action at the alveolar surface although the final injurious response is pulmonary oedema for both gases.     

Effects of lead(II) nitrate and a dithiocarbamate fungicide on the rat lung.

The pulmonary toxicity of two potential environmental pollutants was studied in rats 1, 7 and 30 days after a single intratracheal instillation of lead nitrate and Dithane M-45 (mancoceb), either individually or in various combinations. The cell count, protein, phospholipids and lactate dehydrogenase level were determined in the bronchoalveolar lavage fluid, as were the protein, phospholipids and acid phosphatase contents in the lung tissue. Lead nitrate and Dithane M-45 induced acute inflammation reactions with different features. The effects of mixtures of lead nitrate and Dithane M-45 were found to be different from those of the individual components.     

Early damage indicators in the lung I. Lactate dehydrogenase activity in the airways

The rapid determination of damage in the lung is important in developing screening methods for ranking the toxicity of inhalable pollutants. The presence of lactate dehydrogenase (LDH) activity in the airways was found to be a sensitive indicator of acute toxicity to lung cells. The airway content of LDH increased after bronchopulmonary lavage of Syrian hamsters with increasing amounts of Triton X-100, with a correlation coefficient of 0.98. No increase in iron content of the lavage fluid occurred, indicating that lysed erythrocytes were not the source of the LDH. The isoenzyme pattern of the LDH activity in the lavage fluid suggested the LDH was released from lung cells. The method of detecting early lung injury by the presence of LDH in the airways can be used in one of two ways: The toxic material to be tested may be introduced into the lung by pulmonary lavage and the released LDH may be measured in the same lavage fluid; or in animals exposed to toxicants in aersol form, a lavage can be performed after exposure to obtain a sample of the LDH in the airways.     

Anti-allergic effect of N-acetylneuraminic acid in guinea-pigs.

The in-vivo anti-allergic effect of N-acetylneuraminic acid (NANA) in guinea-pigs passively sensitized with anti-ovalbumin rabbit serum has been studied. NANA (20 mg kg-1 i.v.) inhibited bronchial anaphylaxis and the release of histamine into bronchoalveolar lavage fluid. NANA dose-dependently inhibited heterologous passive cutaneous anaphylaxis and haemorrhaging in the passive Arthus reaction. However, it did not inhibit the release of histamine from sensitized minced lung tissue.     

咖啡对糖尿病大鼠胰岛素分泌、敏感性及氧化应激影响

目的评价咖啡对链脲佐菌素（STZ）诱导的糖尿病大鼠胰岛素敏感性、氧化应激指标及胰腺内胰岛素含量的影响。方法 Wistar大鼠48只,随机分为正常对照组（NC组）、含咖啡因咖啡灌胃组（CC）、去咖啡因咖啡灌胃组（DC）、STZ模型组（S）。CC组和DC组分别以咖啡和去咖啡因咖啡每日灌胃,8周后CC组、DC组、S组均腹腔注射STZ 10 mg kg-1,行口服葡萄糖耐量试验（OGTT）及胰岛素耐量试验（ITT）,测定血浆8-异前列腺素F2α（8-isoPGF2α）和8-羟脱氧鸟苷（8-OHDG）水平,检测胰腺内胰岛素含量。结果 OGTT CC组、DC组、S组均较NC组血糖明显升高。ITT结果 DC组和CC组ITT 30、60、120 min血糖下降比例明显高于S组、与NC组比较血糖下降比例无显著差异。CC组、DC组、S组血浆8-isoPGF2α和8-OHDG水平较NC组明显升高,CC组和DC组8-isoPGF2α和8-OHDG水平显著低于S组。CC组、DC组、S组胰腺内胰岛素含量较NC组显著降低,CC组胰腺内胰岛素水平明显高于DC组和S组。结论含咖啡因咖啡和去咖啡因咖啡均可增加糖尿病大鼠胰岛素敏感性、改善氧化应激;含咖啡因咖啡可增加内源性胰岛素分泌。本研究结果提示含咖啡因和去咖啡因咖啡都可能通过影响氧化应激参与调节糖代谢,含咖啡因咖啡可改善糖尿病大鼠B细胞分泌功能。     

Comparative Physicochemical Characterization of Phospholipids Complex of Puerarin Formulated by Conventional and Supercritical Methods

Purpose The aim of this work was to compare the physicochemical characteristics of the phospholipids complex of puerarin (Pur) prepared by traditional methods (solvent evaporation, freeze-drying and micronization) and a supercritical fluid (SCF) technology. The physicochemical properties of the pure drug and the corresponding products prepared by two different SCF methods were also compared. Methods Solid-state characterization of particles included differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), solubility, dissolution rate and scanning electron microscopy (SEM) examinations. Besides puerarin phospholipids complex (PPC) by four different methods, the solid-state properties of unprocessed, gas antisolvent (GAS) crystallized and solution enhanced dispersion by supercritical fluid (SEDS) precipitated puerarin samples were also compared. Crystallinity was assessed using DSC and XRPD. Drug-phospholipids interactions were characterized using Fourier transform infrared spectroscopy (FTIR). SEM was used to determine any morphological changes. Pharmaceutical performance was assessed in dissolution rate and solubility tests. Result The results of the physical characterization attested a substantial correspondence of the solid state of the drug before and after treatment with GAS technique, whereas a pronounced change in size and morphology of the drug crystals was noticed. The GAS-processed puerarin exhibited a better crystal shape confirmed by DSC, XRPD and IR. Polymorphic change of puerarin during SEDS coupled with the dramatic reduction of the dimensions determined a remarkable enhancement of its solubility and in vitro dissolution rate. Phospholipids complex prepared using supercritical fluid technology showed similar properties of physical state, thermal stability and molecular interaction with phospholipids (PC) to those of corresponding systems prepared by other three conventional methods namely solvent evaporation, freeze-drying and micronization as proved by XRPD, DSC, and FTIR. The best dissolution rate was obtained by SEDS-prepared complex, while the highest solubility was obtained for solvent evaporation method. Conclusion Supercritical fluid technology for the preparation of puerarin and its phospholipids complex has been proven to have significant advantages over the solvent evaporation technique and other conventional methods.