Indomethacin Research Articles

Anomalous Water-Sorption Kinetics in ASDs.

Anomalous water-sorption kinetics in amorphous solid dispersions (ASDs) are caused by the slow swelling of the polymer. In this work, we used a diffusion–relaxation model with the Williams–Landel–Ferry (WLF) equation and the Arrhenius equation to predict the anomalous water-sorption kinetics in ASDs of poly(vinyl-pyrrolidone)-co-vinyl-acetate (PVPVA) and indomethacin (IND) at 25 °C. These predictions were based on the viscosities of pure PVPVA and pure IND, as well as on the water-sorption kinetics in pure PVPVA. The diffusion–relaxation model was able to predict the different types of anomalous behavior leading to a qualitative and quantitative agreement with the experimental data. Predictions and experiments indicated more pronounced anomalous two-stage water-sorption behavior in the ASDs than in pure PVPVA. This was caused by a higher viscosity of glassy ASD–water mixtures compared to glassy PVPVA–water mixtures at the same distance from their glass transition temperature. These results suggest that this ASD swells more slowly than the polymer it is composed of. The modeling approach applied in this work can be used in the future for predicting diffusion-controlled release behavior or swelling-controlled release behavior of ASDs.

Protective Effect of Anwulignan on Gastric Injury Induced by Indomethacin in Mice.

Anwulignan (AN) is a monomer lignan from Schisandra sphenanthera Rehd. et Wits (Schisandra sphenanthera fructus, Schisandra sphenanthera). The protective effect of AN against the indomethacin (IND)-induced gastric injury to mice and the related mechanism of action was investigated in this study. The effect of AN was mainly assessed by observing the gastric tissue morphology, gastric ulcer index (GUI), ulcer inhibition rate (UIR), gastric juice volume (GJV) and pH value. Chemical colorimetry, immunofluorescence, ELISA, and Western blot were used to detect related factors in the gastric tissue. The results showed that AN reduced the GUI, increased the UIR, inhibited the GJV, and increased the gastric pH value. AN significantly increased cyclooxygenase-1, cyclooxygenase-2, and prostaglandin E2 expression levels in the gastric tissue, activated nuclear factor (erythroid-derived 2)-like 2 (Nrf2), increased heme oxygenase-1 expression, enhanced the activity of superoxide dismutase and glutathione peroxidase, and decreased the malondialdehyde content. AN reduced the phosphorylation of nuclear factor-κ gene binding (NF-κB) p65 and its nuclear translocation, the key protein of NF-κB signaling pathway in the gastric tissue, and the content of the pathway downstream signaling molecules, including interleukin-6, interleukin-1β, and tumor necrosis factor-α, to play an anti-inflammatory role. AN inhibited the downstream signals B-cell lymphoma 2-associated x protein and cleaved caspase-3 in gastric tissue, and activated B-cell lymphoma 2, to play an antiapoptotic role, which were further verified by Hoechst staining. Therefore, AN has a significant protection against the gastric injury induced by IND in mice, and the mechanism may be concerned in its activation of Nrf2, inhibition of NF-κB signaling pathway, and anti-apoptotic effect. SIGNIFICANCE STATEMENT: Anwulignan (AN) significantly reduced the indomethacin-induced gastric injury in mice, and its antioxidation, anti-inflammation, and antiapoptosis were considered to be involve in the effect, suggesting that AN should be a potential drug or food supplement for gastric injury induced by indomethacin.

Sasol ECOFT and Deutsche Aircraft join forces to accelerate power-to-liquid (PTL) aiming for carbon-neutral flight

T he dissolution rates of indomethacin (IMC) and nifedipine (NIF) as poorly water-soluble model drugs have been significantly improved by encapsulating their molecules in the porous structure of engineered-particles of lactose as a new biocompatible porous carrier. The formulation method used in this study utilized a template-based spray-drying technique for in-situ production of porous lactose followed by two solvent-based drug-loading methods: (i) adsorption from organic solution, and (ii) incipient wetness impregnation to incorporate the drugs inside the porous lactose. In both cases, the results of DSC and XRD have revealed the deposition of nano-sized crystals of drugs inside the nanopores due to the nanoconfinement phenomenon. Greater extents of drug loadings have been achieved during the indomethacin adsorption due to the hydrogen-bonding interaction with the surface of lactose, as determined by FTIR spectroscopy. The in vitro release studies in simulated gastric fluid (SGF) have shown faster release rates for the impregnated particles compared with drug-loaded particles via the adsorption method.

Comparison study of physicochemical and biopharmaceutics properties of hydrophobic drugs ground by two dry milling processes

This study focuses on the dry milling of biopharmaceutical classification system (BCS) class II molecules. These molecules have a limited bioavailability because of their low aqueous solubility, poor water wettability and low dissolution rate. In order to improve these properties, indomethacin (IND) and niflumic acid (NIF) were milled using two different types of equipment: Pulverisette 0® and CryoMill®. Milled samples were characterized and compared to commercial molecules. IND shows a modified solid state, like surface crystallinity reduction and an increase in water vapor adsorption from to 2- up to 5-fold due to milling processes. The obtained solubility data resulted in an improvement in solubility up to 1.2-fold and an increase in initial dissolution kinetics: 2% of dissolved drug for original crystals against 25% for milled samples. For NIF no crystallinity reduction, no change of surface properties and no solubility improvement after milling were noticed. In addition, milled particles seemed more agglomerated resulting in no changes in dissolution rate compared to the original drug. IND solubility and dissolution enhancement can be attributed to the modification of surface area, drug crystallinity reduction, and water sorption increase due to specific behavior related to the drug crystal disorder induced by milling process.

Electrochemical biosensor based on three components random conjugated polymer with fullerene (C60)

Herein, a conjugated polymer and fullerene bearing architecture-based electrochemical Tyrosinase (Tyr) enzyme inhibition biosensor for indomethacin (INDO) drug active compound has been developed. For this purpose, three moieties of benzoxadiazole, thienopyrroledione, and benzodithiophene containing conjugated polymer; poly[BDT-alt-(TP;BO)] was used as a transducer modifier together with fullerene for catechol detection. The specific combination of these materials is considered an effective way to fabricate highly sensitive and fast response catechol biosensors for the first time. Electrochemical and surface characteristics of the modified electrodes were obtained by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, and atomic force microscopy. The effect of the parameters during chronoamperometric measurements on the biosensor response was also studied. Using optimized conditions, biosensing of catechol was achieved between 0.5 and 62.5 µM with a limit of the detection 0.11 µM. Tyr inhibition was followed with INDO drug active compound and it was found that INDO has a mixed type characteristic of enzyme kinetics with an I50 value of 15.11 µM.

Gelation switch of polyamorphic indomethacin depending on the thermal procedure

Amorphous indomethacin (IMC) prepared under different thermal procedures via melt quenching method showed significantly different dissolution behaviors. This study aims to investigate the influence of thermal procedures on the formation of IMC polyamorphism and to explore the mechanism for their different dissolution behaviors. Amorphous IMC samples were prepared by melting crystalline IMC under a series of temperatures (160–195 °C), respectively, followed by quenching in liquid nitrogen. Samples obtained under 170 °C exhibited bi-halo shapes at ∼15° and ∼26° (2θ), while the ones above 175 °C showed a single halo at ∼21° (2θ), suggesting amorphous IMC prepared under different thermal procedures probably have different local molecular arrangements. In comparison to crystalline IMC, amorphous IMC obtained under 170 °C showed significantly higher dissolution profiles with good dispersibility in aqueous medium, however, all amorphous IMC samples prepared above 175 °C demonstrated much lower dissolution with significant gelation, which seemed like a gelation switch existed for polyamorphic IMC when the preparation temperature was between 170 and 175 °C. Based on physicochemical characterizations, amorphous IMC prepared under 170 °C had higher surface free energy, more surficial hydrophilic groups and better wettability than the ones made above 175 °C. Molecular dynamics simulations revealed that the amorphous samples prepared below 170 °C had similar binding energy values in the range of 310.045–325.479 kcal/mol, while those prepared above 175 °C were significantly lower within 212.193–235.073 kcal/mol. Such binding energy difference might be responsible for their different local molecular arrangements after different thermal procedures. The current study deeply reminds us that the thermal procedure of preparation methods may significantly affect the physicochemical properties of amorphous materials, which should be paid special attention to the polymorphic selection during pharmaceutical development.

Contribution of molecular chiral mesoporous silica nanoparticles in delivering drugs with chiral recognition ability

Among massive study of mesoporous silica nanoparticles, molecular chiral mesoporous silica nanoparticles (MC-MSN) enjoy great interests recently as it may exert special functions in chiral environment. To elucidate its potential abilities as drug carriers, the present work focused on its prominent advantage of chiral recognition in adsorbing and delivering drug molecules, which mainly covered molecular recognition of racemic drugs and chiral delivery of achiral drug by triggering chiral responses in biological environment. The result turned out that the loading capacity of L-alanine was 1.56-fold higher than that of DL-alanine, reminding that MC-MSN had effective molecular recognition function due to its chirality. Furthermore, the peak area ratio of levorotary ofloxacin/dextral ofloxacin from loaded ofloxacin was obviously higher than ofloxacin, confirming that MC-MSN can molecularly recognize levorotary drug. After loading poorly water-soluble drug indometacin (IMC) into MC-MSN, the carrier delivered IMC with improved anti-inflammation effect based on its chiral recognition effect.

Molecular interactions of indomethacin and amino acids: Computational approach

Molecular interactions of indomethacin (IND) and amino acids (AA) were investigated in this work by employing the computational approaches. To this aim, the models of IND-AA were stabilized by performing density functional theory (DFT) calculations yielding the most favorable configurations regarding the energy values. Next, the approach of quantum theory of atoms in molecules (QTAIM) was used to recognize the roles of interactions and their significance in the bimolecular models. The results of interaction energies indicate that tryptophan (TRP) and phenylalanine (PHE) could be considered for participating in strong interactions with the IND substance. The results of QTAIM indicated that not only the electronegative atomic centers, but also homo-atomic centers could play significant roles in formations of IND-AA bimolecular models.

Rivastigmine ameliorates indomethacin experimentally induced gastric mucosal injury via activating α7nAChR with inhibiting oxidative stressand apoptosis.

The current study aimed to investigate the potential ameliorative role of Rivastigmine (RIVA), the anti-Alzheimer drug, against the gastric mucosal injury caused by indomethacin (IND). The rats were divided into four groups: group I was given a vehicle as a control, group II was given RIVA (0.3 mg/kg) once daily intraperitoneal (ip) for 2 weeks, group III was given a single IP dose of 30 mg/kg IND, and group IV was given RIVA ip 2 weeks before the administration of IND. The gastric mucosal injury was detected by the estimation of ulcer index, gastric acidity, pepsin, and mucin concentrations. Malondialdehyde (MDA), superoxide dismutase (SOD), reduced glutathione (GSH), total nitrite/nitrate (NOx), and the expression of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), nuclear factor kappa B (NF-κB), Hemoxygenase 1 (HO-1), and caspase-3 were all measured in gastric tissue. In addition, histological assessment and proliferating cell nuclear antigen (PCNA) immuno-expression were studied. Gastric mucosal injury induced by IND was indicated by both biochemical and histopathological assessments. RIVA Pretreatment reduced ulcer index, MDA, TNF-α, IL-6, NF-κB, and caspase-3 and increased SOD, GSH, NOx, and HO-1. RIVA improved the suppressed nuclear immunoreaction for PCNA observed with IND. The current findings provide novel evidence that RIVA possesses a prophylactic action against IND-induced gastric mucosal damage in rats. Despite being a cholinergic drug that is associated with increased pepsin and stomach acidity, RIVA protected against IND-induced gastric mucosal injury via activating α7nAChR and inhibiting oxidative stress and apoptosis.

Pentapeptide modified ethosomes for enhanced skin retention and topical efficacy activity of indomethacin

Challenges associated with topical analgesics and anti-inflammatory drugs include poor drug penetration and retention at the desired lesion site. Therefore, improving these challenges would help to reduce the toxic and side effects caused by drug absorption into the systemic circulation and improve the therapeutic efficacy of topical therapeutic drugs. Pentapeptide (KTTKS) is a signal peptide in skin tissue, it can be recognized and bound by signal recognition particles. In the current study, we successfully prepared novel indomethacin (IMC) loaded KTTKS-modified ethosomes (IMC-KTTKS-Es), and the physicochemical properties and topical efficacy were investigated. Results showed that the prepared IMC-KTTKS-Es displayed a particle size of about 244 nm, a negative charge, good deformability, and encapsulation efficiency (EE) exceeding 80% for IMC, with a sustained release pattern. In vitro percutaneous permeation studies revealed that the skin retention was increased after the drug was loaded in the IMC-KTTKS-Es. Confocal laser scanning microscopy also showed improved skin retention of IMC-KTTKS-Es. In addition, IMC-KTTKS-Es showed improved topical analgesic and anti-inflammatory activity with no potentially hazardous skin irritation. This study suggested that the IMC-KTTKS-Es might be an effective drug carrier for topical skin therapy with a good safety profile.

Chitosan/sulfobutylether-β-cyclodextrin based nanoparticles coated with thiolated hyaluronic acid for indomethacin ophthalmic delivery

Indomethacin (IND) is topically administered for the treatment of the anterior segment diseases such as conjunctivitis, uveitis, and inflammation prevention for post-cataract surgery, as well as posterior segment diseases as macular edema. Currently IND is available as 0.1% w/v hydroxypropyl-β-cyclodextrin-based eye drop formulation and its bioavailability is limited by several drawbacks such as the nasolacrimal duct draining, the reflex blinking and the low volume of the conjunctival sac. In this study, chitosan (CS)/sulfobutylether-β-cyclodextrin (SBE-β-CD) based nanoparticles (NPs) with a mean diameter of 340 (±7) nm, a ζ-potential value of +18.3 (±0.5) mV and coated with thiolated low molecular weight hyaluronic acid were formulated to improve both the solubility and the residential time in the conjunctival sac of the loaded drug IND. The NPs were prepared through the ionotropic gelation technique, exploiting the interaction between the positively charged amino group of CS and the negatively charged sulfonic group of SBE-β-CD. The mucoadhesive properties of the NPs were evaluated on chicken trachea and esophagus tissues using a texture analyser. The irritability effects of NPs were disclaimed with Hecam test. The developed coated NPs showed increased residential time in the conjunctival sac, displayed no irritancy or toxicity for local administration, making them an optimal and innovative drug delivery system for the treatment of anterior segment inflammation diseases. On the other hand, the uncoated NPs displayed better permeating properties since they are smaller and could be further exploited for the treatment of posterior segment diseases.

Evaluation of Different Surface Coating Agents for Selenium Nanoparticles: Enhanced Anti-Inflammatory Activity and Drug Loading Capacity.

BackgroundInflammation is the keystone in the disease’s pathological process in response to any damaging stimuli. Therefore, any agent that inhibits the inflammatory response is under focus, either a drug or a bioactive compound. Selenium nanoparticles have drawn attention in various biomedical applications, including the anti-inflammatory activity.PurposeIn the current study, we aimed to evaluate the capacity of different surface coating materials (soybean lecithin, PEG 6000, and β-cyclodextrin) to enhance the anti-inflammatory activity of the synthesized selenium nanoparticles (SeNPs). The capability of the coated SeNPs to adsorb indomethacin (IND) on their surfaces compared to the uncoated SeNPs was also evaluated.MethodsSeNPs were synthesized, coated with different materials, and characterized in vitro using X-ray diffraction, UV-Vis spectrophotometer, FTIR, SEM, TEM, and particle size and zeta potential measurements. The in vivo anti-inflammatory activity of the uncoated/coated SeNPs loaded into hydrogel was evaluated using a carrageenan-induced paw edema rat model. The effect of SeNPs surface coatings was further evaluated for IND loading capacity.ResultsOur findings proved the superior anti-inflammatory activity of all coated SeNPs compared to the uncoated SeNPs, especially with β-cyclodextrin surface coating. Regarding the IND loading capacity of the prepared uncoated/coated SeNPs, the amount of drug loaded was 0.12, 1.12, 0.3, and 0.14 µg IND/µg SeNPs for the uncoated, lecithin-, PEG- and β-CD-coated SeNPs, respectively.ConclusionSurface functionalization of SeNPs can provide a synergistic therapeutic activity. Our results are promising for further investigation of the in vivo anti-inflammatory synergistic activity of the IND-loaded surface-coated SeNPs.

Underlying mechanisms of promoted formation of haloacetic acids disinfection byproducts after indometacin degradation by non-thermal discharge plasma

Indometacin (IDM), as a kind of non-steroidal anti-inflammatory drugs, has ecological and health risks, which is the potential precursor of chlorination disinfection byproducts (DBPs). Non-thermal discharge plasma was attempted to eliminate IDM and control subsequent DBPs formation. Satisfactory removal performance for IDM was realized by the plasma oxidation; almost 100% of IDM was removed within 2 min. Relatively greater removal efficiency was gained at a higher plasma voltage and a lower pH level. Electron paramagnetic resonance spectrometer revealed that reactive species ·OH, O2·−, and 1O2 were responsible for IDM decomposition. Based on analyses of Fourier transform infrared spectroscopy, two-dimensional correlation spectroscopy, three-dimensional fluorescence spectrum, and gas chromatography-mass spectrometer, attacks of reactive species resulted in sequence breakages in functional groups of IDM, leading to production of small molecular alcohols, acids, and amines. Possible decomposition pathways of IDM were proposed. The produced acetamide and 1H-indol-5-ol were important precursors of DBPs. Formation and toxicity of nitrogen-containing DBPs were dramatically inhibited after IDM degradation; however, those of haloacetic acids were strengthened. The relevant roadmaps among DBPs and degradation intermediates were figured out. This study revealed the underlying mechanisms of IDM degradation by discharge plasma and its potential risks in chlorination disinfection.

Altered expression of Notch signaling, Tlr receptors, and surfactant protein expression after prostaglandin inhibition may be associated with the delayed labor in LPS-induced mice.

This study aims to investigate whether indomethacin (IND) delays preterm birth by regulating the Notch pathway, Tlr receptors, and Sp-A in the placenta in lipopolysaccharide (LPS)-induced preterm labor (PTL) model. CD-1 mice were distributed to the pregnant control (PC), Sham, PBS, IND (2 mg/kg; i.p.), LPS (25 μg/100 μl; intrauterine), and LPS + IND groups. The injections were performed on day 14.5 of pregnancy. Placentae were collected on day 15.5 of pregnancy, and immunohistochemical analyzes were performed. Differences in staining intensities between the Cox-1, Notch-1 (N1), Dll-1, Jagged-2 (Jag-2), Tlr-2, and Tlr-4 proteins were compared. Preterm labor rates were 100% and 66% (preterm delivery delayed 5 h) in the LPS and LPS + IND groups, respectively. In LPS-treated mice, a general morphological deterioration was observed in the placenta. Total placental mid-sagittal measurement was significantly reduced in the LPS-treated group, while it was similar to the PC group in the LPS + IND group. Cox-1 expression in the LZ increased, and Sp-A expression decreased after LPS injection, and IND administration diminished this increase. N1 expression increased in the labyrinth zone (LZ) and the junctional zone (JZ). Dll-1 and Jag-2 expression increased in the JZ after LPS injection (p < 0.0001). IND administration diminished Tlr-2 expression in the LZ and Tlr-4 expression in the JZ after LPS injection. In conclusion, PG (prostaglandin) inhibition may alter Notch signaling, Tlr, and Sp-A protein expression and may be associated with delayed labor in LPS-induced mice.

Evaluating the effect of kosmotropic inorganic salts in the in vitro dissolution behavior of tablets containing amorphous indomethacin-polyvinylpyrrolidone solid dispersions

The present study evaluates the effect of kosmotropic inorganic salts in the disintegration time and the in vitro dissolution behavior of tablets containing polyvinylpyrrolidone (PVP)-based amorphous solid dispersions (ASDs). Specifically, the impact of KH2PO4, KHCO3 and KCl -which have presented kosmotropic effect on hydrophilic polymers at previous studies- on the performance of tablets containing indomethacin (IND)-PVP ASDs was evaluated. Results showed that all the tested potassium salts presented a kosmotropic effect on PVP, while KH2PO4 was identified as the salt with the greatest impact on PVP's cloud point temperature. Contrary to previously published reports, the in vitro dissolution study of the prepared formulations (with and without inorganic salts) revealed that only the addition of KH2PO4 resulted to increased drug in vitro supersaturation rate and extent. As far as the KHCO3 and KCl are concerned, their incorporation into the systems brought about only a marginal increase in the final level of the API's supersaturation. Interestingly, according to the obtained results, as the inorganic salts' concentration increased, the final supersaturation level of IND decreased in all examined cases. Furthermore, in order to evaluate the moisture-effect on the tablets' performance, pharmaco-technical characterization and in vitro dissolution studies of tablets stored at 60% RH/25 °C took place. Results revealed that the presence of the potassium inorganic salts could not control the moisture's impact on the dissolution profiles and the disintegration time of tablets, highlighting that, in contrary to previous findings, the utilization of kosmotropes salts is not to be considered as a universal solution for the improvement of ASD-based tablet's dissolution/supersaturation performance.

Potential role of carvedilol in intestinal toxicity through NF-κB/iNOS/COX-2/TNF-α inflammatory signaling pathway in rats

Background The increased use of indomethacin (IND) is associated with gastrointestinal injury. This research aims to investigate the effects of a beta-blocker, carvedilol (CAR) on a rat model of IND-induced acute intestinal damage and clarify the probable underlying protective mechanisms. Materials and methods Twenty-four male Wistar rats were divided into four groups. Control group: given vehicles; CAR-treated group: given 10 mg/kg/day CAR PO daily by gastric gavage for 10 consecutive days; IND-treated group: given a single Sc dose of 10 mg/kg IND at the end of the ninth day of the experiment; combined CAR/IND-treated group: given both IND and CAR. Results In the rats that received IND, severe intestinal histopathological changes together with oxidative and nitrosative intestinal stress were present biochemically and immunohistochemically. Obvious inflammatory and tissue damage were represented by the significant intestinal increases in TNF-α, COX-2, and caspase-3 together with the elevated expression of VCAM-1 adhesion molecules. Intestinal gene expression of NF-kB and COX-2 was also increased. Pretreatment with CAR significantly reversed the IND-induced intestinal toxic manifestations. Conclusion CAR has beneficial intestinal protective effects. Its ameliorative action is conferred through its antioxidant, antinitrosative, anti-inflammatory, and antiapoptotic properties.

Low- versus Mid-frequency Raman Spectroscopy for in Situ Analysis of Crystallization in Slurries.

Slurry studies are useful for exhaustive polymorph and solid-state stability screening of drug compounds. Raman spectroscopy is convenient for monitoring crystallization in such slurries, as the measurements can be performed in situ even in aqueous environments. While the mid-frequency region (400–4000 cm–1) is dominated by intramolecular vibrations and has traditionally been used for such studies, the low-frequency spectral region (<200 cm–1) probes solid-state related lattice vibrations and is potentially more valuable for understanding subtle and/or complex crystallization behavior. The aim of the study was to investigate low-frequency Raman spectroscopy for in situ monitoring of crystallization of an amorphous pharmaceutical in slurries for the first time and directly compare the results with those simultaneously obtained with mid-frequency Raman spectroscopy. Amorphous indomethacin (IND) slurries were prepared at pH 1.2 and continuously monitored in situ at 5 and 25 °C with both low- and mid-frequency Raman spectroscopy. At 25 °C, both spectral regions profiled amorphous IND in slurries as converting directly from the amorphous form toward the α crystalline form. In contrast, at 5 °C, principal component analysis revealed a divergence in the detected conversion profiles: the mid-frequency Raman suggested a direct conversion to the α crystalline form, but the low-frequency region showed additional transition points. These were attributed to the appearance of minor amounts of the ε-form. The additional solid-state sensitivity of the low-frequency region was attributed to the better signal-to-noise ratio and more consistent spectra in this region. Finally, the low-frequency Raman spectrum of the ε-form of IND is reported for the first time.

Pharmacological Preconditioning by Corticotropin Releasing Factor (CRF) or ACTH Protects the Gastric Mucosa against Ulcerogenic Action of Indomethacin through Involvement of Glucocorticoids

Non‐steroidal anti‐inflammatory drugs (NSAIDs) are widely used as analgesic and anti‐inflammatory drugs. However, adverse effects, including gastrointestinal, renal, cardiovascular side effects, seriously complicate NSAIDs use. Their gastrointestinal side effects are the most known serious complications in patients taking these drugs. Previously we have shown that preconditioning stress attenuates the ulcerogenic action of indomethacin (IM) on the gastric mucosa. According our findings glucocorticoids, released in response to stressor, are gastroprotective hormones and involved in stress preconditioning protective effects. Corticotropin releasing factor (CRF), a major mediator of stress response, stimulates ACTH release through CRF receptors of subtype 1 and ACTH, in turn, stimulates glucocorticoid production. Here we verify the hypothesis that pharmacological preconditioning by CRF or ACTH can protect the gastric mucosa against ulcerogenic action of IM in rats through mechanism associated with glucocorticoids. For this, preliminary fasted (24 h) rats were administered by CRF (2.5 or 5 µg/ kg, ip) or ACTH (1U/kg, ip) 30 min before IM injection (35 mg/kg, sc). Gastric lesions were examined 4 h after IM administration. Plasma corticosterone levels were measured before and 4 h after IM injection. Since the gastrointestinal injury is accompanied by changes in somatic pain sensitivity, we also measured tail flick latencies (tail flick test) before and 4 h after IM. Both CRF and ACTH by itself caused an elevation of plasma corticosterone levels, which was accompanied by an increase of tail flick latencies (analgesic effect). IM administration resulted in the gastric erosion 4 h later. Pretreatment with CRF or ACTH reduced an area of gastric lesions caused by IM (gastroprotective effect). IM‐induced gastric injury was accompanied by an increase of tail flick latencies, which was prevented by CRF (normalization of somatic pain sensitivity). To estimate the role of glucocorticoids in CRF‐induced gastroprotection an inhibitor of corticosterone synthesis metyrapone (30 mg/kg) or CRF receptor type 1 antagonist NBI 27914 (10 mg/kg) or glucocorticoid receptor antagonist RU‐38486 (20 mg/kg) was administered before CRF. Both metyrapone and NBI 27914 injected before CRF administration caused an inhibition of CRF‐induced corticosterone response and prevented protective effect of CRF on the gastric mucosa against the IM‐induced injury. The gastroprotective effect of CRF was also eliminated by the pretreatment with RU‐38486. Thus, CRF as well as ACTH can protect the gastric mucosa against ulcerogenic action of IM. Gastroprotective action of CRF accompanied by normalization of somatic pain sensitivity is provided by mechanism associated with glucocorticoids.

Repeated Treadmill Running Attenuates Indomethacin‐caused Gastric Injury in Rats with Streptozotocin‐induced Diabetes

Diabetes is one of the most common chronic diseases leading to disability and death. Physical activity has a beneficial effect on all vital functions of the body under the norm as well as pathology including diabetes. Previously we have shown that treadmill running attenuates the vulnerability of gastric mucosa to ulcerogenic action of indomethacin (IM). The aim of the study was to investigate the effect of treadmill running on the vulnerability of the gastric mucosa to ulcerogenic action of IM in rats with streptozotocin‐induced diabetes. Diabetes was induced by a single injection of streptozotocin (STZ, 70 mg/kg, ip). Two regimens of treadmill running, repeated (Experiment 1) and single (Experiment 2), were used. There were four groups of rats in each experiment: two groups (running and sedentary) treated with STZ and two groups (running and sedentary) treated with vehicle of STZ (control). In Experiment 1 daily repeated treadmill running was initiated 7 days before STZ (or its vehicle) administration and continued daily 7 days after STZ administration. The intensity and duration of treadmill running gradually increased from 10 to 15 cm/s and from 10 to 20 min/day, respectively. In Experiment 2 only single treadmill session (15 cm/s, 15 min) was initiated 7 days after STZ (or its vehicle) administration. In both experiments, IM (35 mg/kg, sc) was administered immediately after completion of treadmill session in preliminary (24 h) fasted rats 7 days after STZ injection. Gastric erosion was examined 4 h after IM administration. Glucose level, body weight, water consumption and plasma corticosterone levels were also measured. Signs of diabetes (an increase of glucose level, loss of body weight, an increase of water consumption and elevation of plasma corticosterone levels) were developed 1 week after STZ administration. IM administration caused the gastric erosion 4 h after the injection. STZ‐induced diabetes aggravated ulcerogenic action of IM: the mean area of gastric erosion was significantly greater in rats with STZ injection compared to that in control animals. Repeated as well as single treadmill running did not significantly affect the signs of diabetes. However, repeated daily treadmill running resulted in a significant decrease of the area of gastric erosion in rats with STZ‐induced diabetes as well as control (non‐diabetic) rats compared to corresponding sedentary groups. A single running, before IM administration, reduced the area of gastric erosion in non‐diabetic rats, but it did not affect the gastric injury in rats with STZ‐induced diabetes. The data suggest that regular physical activity started before STZ‐induced diabetes can protect the gastric mucosa against the ulcerogenic action of IM.

Spray-dried indomethacin-loaded polymeric micelles for the improvement of intestinal drug release and permeability

Current study aimed to develop a spray-dried powder containing indomethacin (IND)-loaded polymeric micelles which can be administered perorally as a dissolved powder to enhance the drug release and permeability of the active substance. The resulting low dense spray-dried spherical particles have decreased particle size (7.21 µm) in monodisperse distribution. The polymeric micelles had a nano size range (130 nm) also in monodisperse size distribution. These nanoparticulate properties and the high encapsulation efficiency (> 80%) lead to the improvement of gastrointestinal drug release in fasted and fed state conditions. Following second order and Higuchi kinetics, a rapid drug release was experienced exceeding the initial IND suspension. In vitro cell line studies on Caco-2 human colorectal adenocarcinoma cells showed that the formulation does not increase the toxicity of initial IND, therefore can be considered safe for oral application. Ex vivo semiquantitative and quantitative studies were performed on porcine small intestine where increased flux and permeability values of IND were achieved. The physical stability of the solid formulation was sufficient through a 6-month intermediate study caused by the hydrogen-bond formation between IND and the micelle-forming co-polymer.