Anti-inflammatory and Immunomodulatory Potency of Selenium-Enriched Probiotic Mutants in Mice with Induced Ulcerative Colitis.

Selenium-enriched Lactobacillus plantarum and Bifidobacterium longum mutants were used as a protector against Piroxicam-induced ulcerative colitis (UC). In this study, 32 BALB/c male mice were distributed to four groups: the control group, the Piroxicam group which was given 0.8 mg Piroxicam, SP and SB groups which were given 0.8 mg Piroxicam, and plus Lactobacillus plantarum and Bifidobacterium longum selenium-enriched mutants, respectively. Bodyweight; serum content of IgG, IgM, TNF-α, IL-2, IL-6, and IL-10; CBC; myeloperoxidase enzyme activity; histopathological examination of colon and spleen; and expression of TNF-α, IL-2, IL-6, and IL-10 genes in colon and spleen with qRT-PCR were determined. Bodyweight was found to reduce in the Piroxicam group and then recovery in the SB group. Serum content of IgG, IL-2, and IL-10 reduced in the Piroxicam group, whereas IgG, TNF-α, and IL-6 increased in the Piroxicam group in comparison to the other groups. Myeloperoxidase activity witnessed a significant increase in the Piroxicam group compared with the other groups. No significant differences were observed between all groups in measurements of red cells, hemoglobin, neutrophil, monocyte, eosinophil, and basophil in blood. Meanwhile, the white blood cells and platelets recorded the highest and lowest value, respectively, in the Piroxicam group. The colon of the Piroxicam group showed a noticeably massive infiltration of inflammatory cells in the lamina propria. These inflammations were mildly reduced in the SP group, while the reduction in the SB group was significant. In the Piroxicam group, splenic parenchyma saw an increase in the number of melanomacrophages, while hypertrophic plasma cells were observed in the SP group. The spleen of the SB group exhibits a nearly normal form. TNF-α and IL-6 genes had significantly upregulated in the colon of the Piroxicam group compared to the control group, while they were significantly downregulated in the SB group. In contrast, IL-2 and IL-10 genes had upregulated in the colon of the SB group compared to the control groups, while they had downregulated in the Piroxicam group. The expression of these genes had not recorded significant differences between all groups in the spleen. Therefore, this study recommends Bifidobacterium longum selenium-enriched mutants as anti-inflammatory and immunomodulatory supplements.

Alloimperatorin from Ammi majus fruits mitigates Piroxicam-provoked gastric ulcer and hepatorenal toxicity in rats via suppressing oxidative stress and apoptosis.

INTRODUCTION: Fruits of Ammi majus, commonly called bishop's weed, contain a significant amount of furanocoumarins. Alloimperatorin (Allo, 6) was isolated from the free coumarin fraction of fruits, beside 8-hydroxypsoralen (1), methoxsalen (2), heraclin (3), isoimperatorin (4), imperatorin (5), isoheraclenin (7) and heraclenin hydrate (8). Piroxicam (Px) is a widely used pain-relieving drug that demonstrated side effects, including gastric ulceration and hepatorenal toxicity. OBJECTIVE: This study aimed to investigate the protective potential of Alloimperatorin against Px-induced gastric ulceration and hepatorenal toxicity. MATERIAL & METHODS: Rats were divided into four groups: Negative control, Px-induced rats, Allo + Px co-treated group, and Pc + Px co-treated group. Allo (25 mg/kg body weight) and Pc (25 mg/kg body weight) treatments were received 5 days before and 4 days after Px intoxication for 4 days (50 mg/kg body weight). Serum prostaglandin E2 (PG-E2) and liver and kidney functions were measured. Oxidative stress markers were evaluated in the three tissues. Histopathological features and caspase-3 immunoexpression were monitored. RESULTS & DISCUSSION: Px triggered gastric ulceration, increased indices of liver and kidney functions, decreased PG-E2 levels, provoked oxidative stress, and activated caspase-3 immunoexpression. Co-treatment with Allo demonstrated protective activities. CONCLUSION: Alloimperatorin exhibited anti-oxidative, anti-inflammatory, and anti-apoptotic activities.

Bilosomes as Promising Nanovesicular Carriers for Improved Transdermal Delivery: Construction, in vitro Optimization, ex vivo Permeation and in vivo Evaluation.

PURPOSE: The goal of this research was to enhance the transdermal delivery of lornoxicam (LX), using nanovesicular carriers composed of the bile salt sodium deoxycholate (SDC), soybean phosphatidyl choline (SPC) and a permeation enhancer limonene. METHODS: Thin-film hydration was the technique employed for the fabrication using a Box-Behnken design with three central points. The investigated factors were SPC molar concentration, SDC amount in mg and limonene percentage (%). The studied responses were percent entrapment efficiency (%EE), particle size (PS), polydispersity index (PDI), zeta potential (ZP), and in vitro drug release (after 2, 10 h). In order to obtain the optimum formula, numerical optimization by Design-Expert® software was used. Electing the optimized bilosomal formula was based on boosting %EE, ZP (as absolute value) and in vitro drug release, taking in consideration diminishing PS and PDI. Further assessment of the selected formula was achieved by transmission electron microscopy (TEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), stability testing, ex vivo skin permeation and deposition. The in vivo pharmacodynamics activities of the optimized formula were examined on male rats and mice and compared to that of the oral market product. RESULTS: The optimized bilosomal formula demonstrated to be nonirritant, with noticeably enhanced anti-inflammatory and antinociceptive activities. Superior in vivo permeation was proved by confocal laser scanning microscopy (CLSM). CONCLUSION: The outcomes demonstrated that bilosomes could improve transdermal delivery of lornoxicam.

Cadmium overload modulates piroxicam-regulated oxidative damage and apoptotic pathways.

Cadmium (Cd) is a common environmental pollutant that threatens humans' and animals' health. Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used drugs due to their wide therapeutic action; however, they have significant side effects. Since, under many circumstances, humans and animals may be co-exposed to Cd and NSAIDs, the current investigation was assigned to explore the intertwining relationship between Cd and NSAIDs. Four groups of male Wister rats were used: control group: rats received saline; Cd group: rats received cadmium (Cd, 2 mg/kg) orally; Px group: rats received a NSAID (piroxicam, Px, 7 mg/kg, i.p.); and Cd+Px group: rats received both Cd+Px. All treatments were given once a day for 28 consecutive days. Then, blood samples, stomach, liver, and kidney tissues were collected. The results indicated that Px provoked gastric ulcer indicated by high ulcer index, while Cd had no effect on the gastric mucosa. In addition, treatment with Cd or Px alone significantly induced liver and kidney injuries indicated by serum elevations of AST, ALT, ALP, ALB, total protein, creatinine, and urea along with histopathological alterations. Significant increases in malondialdehyde and reduction in GSH and CAT contents were reported along with up-regulated expression of Bax and Bcl-2 after Cd or Px exposure. However, when Cd and Px were given in a combination, Cd obviously potentiated the Px-inflicted cellular injury and death in the liver and kidney but not in the stomach when compared to their individual exposure. This study concluded that oxidative stress mechanisms were supposed to be the main modulator in promoting Cd and Px toxicities when given in combination.

Pectin, beta-cyclodextrin, chitosan and albumin based gastroprotective systems for piroxicam maleate: Synthesis, characterization and biological evaluation.

In order to optimize drug action, new drug formulations have been developed based upon the prodrug approach. This study was inspired by the increasing interest in the field of macromolecular prodrugs and Piroxicam maleate was used as a model drug. A total of five prodrugs were synthesized using beta cyclodextrin, chitosan, pectin, egg albumin, bovine serum albumin. The synthesized conjugates were characterized on the basis of UV, IR and NMR techniques. In-vitro hydrolysis studies were carried out at pH 1.2, pH 7.4, pH 9.0 and in 80% human plasma followed by in-vivo evaluation of analgesic, anti-inflammatory and anti-ulcerogenic potential. The extent of hydrolysis was found to be proportional to increase in pH. Beta cyclodextrin conjugate was found to possess significant analgesic activity whereas chitosan conjugate was found to be the best anti-inflammatory. Pectin conjugate provided maximum protection against ulcers.

Polysaccharides based gastroretentive system to sustain piroxicam release: Development and in vivo prolonged anti-inflammatory effect.

A gastro-retentive delivery system loaded with piroxicam with a bimodal release profile in gastrointestinal-tract was developed. Piroxicam is characterized by high oral absorption, long half-life, but its elimination is impaired in elderly patients. To overcome fluctuations in plasma levels, floating gastro-retentive gel-beads with sustained release properties were manufactured using prilling. Beads matrix was designed as a hollow/multipolymeric system based on alginate, ALM-pectin and hydroxypropilmethylcellulose. This research studied variables able to affect particles micromeritics, hollow inner structure, floating properties and drug-release profiles in gastro-intestinal tract. The gastro-retentive formulation (F4) acted as a floating-system able to provide the desired bimodal drug-release pattern controlling and delaying in vitro piroxicam release. The in vivo anti-inflammatory activity of the floating beads resulted prolonged up to 48 h, compared to standard piroxicam. This formulation may be proposed to treat chronic inflammatory-diseases in elderly patients, needing a rapid onset of drug action followed by a maintenance dose.

Interaction of a common painkiller piroxicam and copper-piroxicam with chromatin causes structural alterations accompanied by modulation at the epigenomic/genomic level.

BACKGROUND: NSAIDs are the most common class of painkillers and anti-inflammatory agents. They also show other functions like chemoprevention and chemosuppression for which they act at the protein but not at the genome level since they are mostly anions at physiological pH, which prohibit their approach to the poly-anionic DNA. Complexing the drugs with bioactive metal obliterate their negative charge and allow them to bind to the DNA, thereby, opening the possibility of genome level interaction. To test this hypothesis, we present the interaction of a traditional NSAID, Piroxicam and its copper complex with core histone and chromatin. METHODS: Spectroscopy, DLS, and SEM studies were applied to see the effect of the interaction on the structure of histone/chromatin. This was coupled with MTT assay, immunoblot analysis, confocal microscopy, micro array analysis and qRT-PCR. RESULTS: The interaction of Piroxicam and its copper complex with histone/chromatin results in structural alterations. Such structural alterations can have different biological manifestations, but to test our hypothesis, we have focused only on the accompanied modulations at the epigenomic/genomic level. The complex, showed alteration of key epigenetic signatures implicated in transcription in the global context, although Piroxicam caused no significant changes. We have correlated such alterations caused by the complex with the changes in global gene expression and validated the candidate gene expression alterations. CONCLUSION AND GENERAL SIGNIFICANCE: Our results provide the proof of concept that DNA binding ability of the copper complexes of a traditional NSAID, opens up the possibility of modulations at the epigenomic/genomic level.

Alkylglycerol Derivatives, a New Class of Skin Penetration Modulators.

The absorption modulating activity of two alkylglycerol derivatives (batyl and chimyl alcohol) on skin barrier properties was evaluated. Biophysical tests such as transepidermal water loss (TEWL) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, as well as in vitro skin permeation studies, were performed in order to determine the effect of these compounds as chemical absorption modulators. Four drugs were used as models: three NSAIDS (diclofenac, naproxen, and piroxicam) and glycyrrhizic acid. The results showed that treatment of the skin with alkylglycerols caused (i) a reduction on the amount of drug permeated; (ii) a reduction in TEWL; and (iii) changes in the ATR-FTIR peaks of stratum corneum lipids, indicative of a more ordered structure. All of these findings confirm that alkyl glycerols have an absorption retarding effect on the drugs tested. Such effects are expected to give rise to important applications in the pharmaceutical and cosmetic sectors, in cases where it is desirable for the drug to remain in the superficial layers of the skin to achieve a local effect.

In vivo Piroxicam Metabolites: Possible Source for Synthesis of Central Nervous System (CNS) Acting Depressants.

BACKGROUND: Piroxicam has been reported to be convertible to Central Nervous System (CNS) acting agents. It has serious depressant effects at high doses. OBJECTIVE: In view of this, structures of piroxicam metabolites were assessed for possible conversion to CNS depressants. METHODS: Literature search was carried out with intent to identifying piroxicam metabolites and the possibility of converting them to CNS acting depressants. RESULTS: Piroxicam is convertible to hydroxymethylated metabolite which may be converted to barbiturates such as thiopentone and thiamylal. Whereas cyclodehydrated metabolite may be converted to acetylcyclodehydrated compound that may be in turn converted to acetylacetone and cyclohexamide. However, carboxybenzothiazine metabolite may be converted to carboxamide compound, benzolactone which is convertible to phenazone. Carboxybenzothiazine is also convertible to 2-aminopyridine mepyramine and triplenamine. Conversion of carboxybenzothiazine to gamma aminobutyric acid and phenothiazines such as chlorpromazine, thioridazine, fluphenazine and perphenazine is highly possible. CONCLUSION: Structurally, barbituric compounds, carboxamide, cyclodehydrated, benzothiazine and carboxybenzothiazine metabolites may act via dopamine and adrenergic receptors causing depression of CNS activities. Piroxicam metabolites may also act via histamine, melatonin and potassium channel receptors causing CNS depression.

Injectable long acting chitosan/tripolyphosphate microspheres for the intra-articular delivery of lornoxicam: Optimization and in vivo evaluation.

Chitosan microspheres were formulated for the intra-articular delivery of lornoxicam in knee osteoarthritis, to minimize associated side-effects after prolonged oral administration. Ionotropic-gelation technique was employed using tripolyphosphate as anionic cross-linker. Full-factorial design experiment was conducted to optimize lornoxicam entrapment-efficiency%. Formulations were assessed for their particle size, in-vitro drug release, Scanning electron microscopy, Differential-scanning-calorimetry and Fourier transform infra-red spectroscopy studies. Changing independent variables, chitosan pH, TPP pH and lornoxicam concentration resulted in different values of entrapment-efficiency% ranging from 13.5%±0.35 to 59.5%±2.2. Particle size ranged from 3.57µm±0.02 to 6.12µm±0.00 and lornoxicam%release was prolonged for up to 8days. SEM results showed spherical shape of the microspheres. FTIR and DSC studies confirmed the crosslinking of chitosan with tripolyphosphate. In-vivo therapeutic effect of lornoxicam microspheres was investigated using Monosodiumiodoacetate (MIA) induced osteoarthritis model in rats. Optimized formula showed long-term in-vivo anti-inflammatory effect relative to lornoxicam solution injected intra-articularly with significant reduction of histological, inflammatory and biochemical parameters of osteoarthritis.

Small Mismatches in Fatty Acyl Tail Lengths Can Effect Non Steroidal Anti-Inflammatory Drug Induced Membrane Fusion.

Biological membranes are made up of a variety of lipids with diverse physicochemical properties. The lipid composition modulates different lipidic parameters, such as hydration, dynamics, lipid packing, curvature strain, etc. Changes in these parameters affect various membrane-mediated processes, such as membrane fusion which is an integral step in many biological processes. Packing defects, which originate either from mismatch in the headgroup region or in the hydrophobic acyl tail region, play a major role in modulating membrane dynamics. In this study, we demonstrate how even a small mismatch in the fatty acyl chain length, achieved by incorporation of low concentrations (up to 30 mol %) of dipalmitoylphosphatidylcholine (DPPC) into dimyristoylphosphatidylcholine (DMPC) small unilamellar vesicles (SUVs), alters several lipidic parameters like packing, dynamics, and headgroup hydration. This in turn affects non steroidal anti-inflammatory drug (NSAID) induced membrane fusion. Dynamic light scattering, differential scanning calorimetry, second-derivative absorption spectrophotometry, and steady-state and time-resolved fluorescence have been used to elucidate the effect of small mismatch in the tails in DMPC/DPPC mixed vesicles and how it modulates membrane fusion induced by the oxicam NSAIDs, meloxicam (Mx), piroxicam (Px), and tenoxicam (Tx). Fusion kinetics was monitored using fluorescence based fusion assays. At low DPPC concentration of 10 mol %, additional fluidization promotes lipid mixing to some extent for Mx, but at higher mol % of DPPC, subsequent increase in rigidity of membrane interior along with increase in headgroup hydration, synergistically inhibits fusion to various extents for the three different drugs, Mx, Px, and Tx.

Polypyrrole nanoparticles for tunable, pH-sensitive and sustained drug release.

We report the development of a generalized pH-sensitive drug delivery system that can release any charged drug preferentially at the pH range of interest. Our system is based on polypyrrole nanoparticles (PPy NPs), synthesized via a simple one-step microemulsion technique. These nanoparticles are highly monodisperse, stable in solution over the period of a month, and have good drug loading capacity (∼15 wt%). We show that PPy NPs can be tuned to release drugs at both acidic and basic pH by varying the pH, the charge of the drug, as well as by adding small amounts of charged amphiphiles. Moreover, these NPs may be delivered locally by immobilizing them in a hydrogel. Our studies show encapsulation within a calcium alginate hydrogel results in sustained release of the incorporated drug for more than 21 days. Such a nanoparticle-hydrogel composite drug delivery system is promising for treatment of long-lasting conditions such as cancer and chronic pain which require controlled, localized, and sustained drug release.

Evaluation of protein undernourishment on the condylar process of the Wistar rat mandible correlation with insulin receptor expression

The mandible condylar process cartilage (CP) of Wistar rats is a secondary cartilage and acts as a mandibular growth site. This phenomenon depends on adequate proteins intake and hormone actions, including insulin. Objectives The present study evaluated the morphological aspects and the expression of the insulin receptor (IR) in the cartilage of the condylar process (CP) of rats subjected to protein undernourishment. Material and Methods The nourished group received a 20% casein diet, while the undernourished group (U) received a 5% casein diet. The re-nourished groups, R and RR, were used to assess the effects of re-nutrition during puberty and adulthood, respectively. CPs were processed and stained with picro-sirius red, safranin-O and azocarmine. Scanning electron microscopy and immunohistochemistry were also performed. Results The area of the CP cartilage and the number of cells in the chondroblastic layer decreased in the U group, as did the thickness of the CP layer in the joint and hypertrophic layer. Renourishment during the pubertal stage, but not during the adult phase, restored these parameters. The cell number was restored when re-nutrition occurred in the pubertal stage, but not in the adult phase. The extracellular matrix also decreased in the U group, but was restored by re-nutrition during the pubertal stage and further increased in the adult phase. IR expression was observed in all CPs, being higher in the chondroblastic and hypertrophic cartilage layers. The lowest expression was found in the U and RR groups. Conclusions Protein malnutrition altered the cellularity, the area, and the fibrous cartilage complex, as well as the expression of the IRs. .

Investigating the potential of employing bilosomes as a novel vesicular carrier for transdermal delivery of tenoxicam.

Bilosomes represent an evolving vesicular carrier that have been explored for oral vaccines delivery based on its ability to resist enzymes and bile salts in the gastrointestinal tract (GIT). Bilosomes vesicles are formed of bilayer membrane of non-ionic surfactant molecules encompassing bile salts. Although, bilosomes have not been proposed for transdermal drug delivery, this carrier seems to have promising potential in this regard. Accordingly, the aim of this investigation was to assess the capability and safety of utilizing bilosomes for transdermal delivery of tenoxicam (TX) as a model drug. A 3(1)2(2) full factorial design was adopted to study the effects of different formulation parameters on bilosomes properties and select the optimal formulation using Design-Expert(®) software. The selected formulation displayed nano-sized spherical vesicles (242.5 ± 6.43nm) with reasonable entrapment efficiency percent (68.33 ± 2.33%). Confocal laser scanning microscopy confirmed the capability of the flourolabeled bilosomes to penetrate deep within the skin. Both, ex vivo permeation and in vivo skin deposition studies confirmed the superiority of bilosomes over drug solution in delivering TX transdermally. In addition, in vivo histopathological study proved the safety of topically applied bilosomes. In summary, the highlighted results confirmed that bilosomes can be further adopted for delivering drugs transdermally.

Efficacy of piroxicam plus cisplatin-loaded PLGA nanoparticles in inducing apoptosis in mesothelioma cells.

PURPOSE: Combined treatment based on cisplatin-loaded Poly(D,L-lactic-co-glicolic)acid (PLGA) nanoparticles (NP-C) plus the NSAID piroxicam was used as novel treatment for mesothelioma to reduce side effects related to cisplatin toxicity. METHODS: PLGA nanoparticles were prepared by double emulsion solvent evaporation method. Particle size, drug release profile and in vitro cellular uptake were characterized by TEM, DLS, LC/MS and fluorescence microscopy. MSTO-211H cell line was used to analyse NP-C biological efficacy by FACS and protein analysis. RESULTS: Cisplatin was encapsulated in 197 nm PLGA nanoparticles with 8.2% drug loading efficiency and 47% encapsulation efficiency. Cisplatin delivery from nanoparticles reaches 80% of total encapsulated drug in 14 days following a triphasic trend. PLGA nanoparticles in MSTO-211H cells were localized in the perinuclear space NP-C in combination with piroxicam induced apoptosis using a final cisplatin concentration 1.75 fold less than free drug. Delivered cisplatin cooperated with piroxicam in modulating cell cycle regulators as caspase-3, p53 and p21. CONCLUSIONS: Cisplatin loaded PLGA nanoparticles plus piroxicam showed a good efficacy in exerting cytotoxic activity and inducing the same molecular apoptotic effects of the free drugs. Sustained cisplatin release allowed to use less amount of drug, decreasing toxic side effects. This novel approach could represent a new strategy for mesothelioma treatment.

Semi solid matrix formulations of meloxicam and tenoxicam: an in vitro and in vivo evaluation.

The objective of this study was to improve the dissolution and subsequently the therapeutic efficacy of poorly water soluble BCS class-II drugs meloxicam and tenoxicam, by lipid semi solid matrix (SSM) systems filled in hard gelatin capsules by liquid fill technology. The present research involved preparation of SSM formulations using Gelucire 44/14 as a carrier due to its self emulsifying, wetting and hydrophilic properties. The SSM capsules were characterized by assay, in vitro dissolution studies, moisture uptake, FTIR and DSC. The optimized formulations were also evaluated for their in vivo anti inflammatory activity in rat model. Six to ten fold enhancement in vitro drug release, in both acidic and basic media, was obtained with formulations containing drug to carrier in 1:6 ratio. The absence of drug peak in DSC scans indicated complete dissolution of the drug in carrier, while IR revealed no chemical interaction of pure drug and Gelucire 44/14. The optimized SSM formulations of meloxicam and tenoxicam showed a rapid decrease in paw edema with a significant increase in anti-inflammatory activity. The SSM formulations were successful in providing rapid release of drugs with improved dissolution and in vivo anti-inflammatory activity by liquid fill technology in hard gelatin capsules.

A mononuclear zinc(II) complex with piroxicam: crystal structure, DNA- and BSA-binding studies; in vitro cell cytotoxicity and molecular modeling of oxicam complexes.

A new mononuclear Zn(II) complex, trans-[Zn(Pir)2(DMSO)2], where Pir(-) is 4-hydroxy-2-methyl-N-2-pyridyl-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide (piroxicam), has been synthesized and characterized. The crystal structure of the complex was obtained by the single crystal X-ray diffraction technique. The interaction of the complex with DNA and BSA was investigated. The complex interacts with FS-DNA by two binding modes, viz., electrostatic and groove binding (major and minor). The microenvironment and the secondary structure of BSA are changed in the presence of the complex. The anticancer effects of the seven complexes of oxicam family were also determined on the human K562 cell lines and the results showed reasonable cytotoxicities. The interactions of the oxicam complexes with BSA and DNA were modeled by molecular docking and molecular dynamic simulation methods.

Modulation of non steroidal anti-inflammatory drug induced membrane fusion by copper coordination of these drugs: anchoring effect.

Membrane fusion, an integral event in several biological processes, is characterized by several intermediate steps guided by specific energy barriers. Hence, it requires the aid of fusogens to complete the process. Common fusogens, such as proteins/peptides, have the ability to overcome theses barriers by their conformational reorganization, an advantage not shared by small drug molecules. Hence, drug induced fusion at physiologically relevant drug concentrations is rare and occurs only in the case of the oxicam group of non steroidal anti-inflammatory drugs (NSAIDs). To use drugs to induce and control membrane fusion in various biochemical processes requires the understanding of how different parameters modulate fusion. Also, fusion efficacy needs to be enhanced. Here we have synthesized and used Cu(II) complexes of fusogenic oxicam NSAIDs, Meloxicam and Piroxicam, to induce fusion in model membranes monitored by using DSC, TEM, steady-state, and time-resolved spectroscopy. The ability of the complexes to anchor apposing model membranes to initiate/facilitate fusion has been demonstrated. This results in better fusion efficacy compared to the bare drugs. These complexes can take the fusion to its final step. Unlike other designed membrane anchors, the role of molecular recognition and strength of interaction between molecular partners is obliterated for these preformed Cu(II)-NSAIDs.

Oxicams bind in a novel mode to the cyclooxygenase active site via a two-water-mediated H-bonding Network.

Oxicams are widely used nonsteroidal anti-inflammatory drugs (NSAIDs), but little is known about the molecular basis of the interaction with their target enzymes, the cyclooxygenases (COX). Isoxicam is a nonselective inhibitor of COX-1 and COX-2 whereas meloxicam displays some selectivity for COX-2. Here we report crystal complexes of COX-2 with isoxicam and meloxicam at 2.0 and 2.45 angstroms, respectively, and a crystal complex of COX-1 with meloxicam at 2.4 angstroms. These structures reveal that the oxicams bind to the active site of COX-2 using a binding pose not seen with other NSAIDs through two highly coordinated water molecules. The 4-hydroxyl group on the thiazine ring partners with Ser-530 via hydrogen bonding, and the heteroatom of the carboxamide ring of the oxicam scaffold interacts with Tyr-385 and Ser-530 through a highly coordinated water molecule. The nitrogen atom of the thiazine and the oxygen atom of the carboxamide bind to Arg-120 and Tyr-355 via another highly ordered water molecule. The rotation of Leu-531 in the structure opens a novel binding pocket, which is not utilized for the binding of other NSAIDs. In addition, a detailed study of meloxicam·COX-2 interactions revealed that mutation of Val-434 to Ile significantly reduces inhibition by meloxicam due to subtle changes around Phe-518, giving rise to the preferential inhibition of COX-2 over COX-1.

In vitro & in vivo studies on lornoxicam loaded nanoemulsion gels for topical application.

The objective of this work was to increase the solubility, in vitro skin permeability of lornoxicam from semisolid topical formulations and also to investigate the in vivo potential of nanoemulsion formulation. Optimized lornoxicam loaded nanoemulsion was prepared successfully by spontaneous self-emulsification method and the size of the stable formulations was found within the range of 102 to 200 nm. The stable nanoemulsion formulations characterized for viscosity, droplet size, transmission electron microscopy (TEM) and refractive index. In vitro permeation rate of nanoemulsion and conventional gel of lornoxicam (LX) were determined. Prmeability parameters like steady-state flux (Jss), permeability coefficient (Kp), and enhancement ratio (Er) were significantly increased in nanoemulsion NE8 and the nanogel NG8 as compared to conventional gel (LG). In vivo studies revealed a significant increase in anti-inflammatory effects as compared with conventional gel of LX. The anti-inflammatory effects of formulation NG8 showed a significant increase in percent inhibition value when compared with control, this difference was found to be highly significant (p<0.001). This work shows for the first time that lornoxicam can be formulated into nanoemulsions and may show promise in enhancing solubility and permeation.