Self-assembling Organogels Loaded with Tenoxicam for Local Intensive Pain and Inflammation Cure: In Vitro and In Vivo Correlation

Due to tenoxicam (TX)'s poor aqueous solubility (0.072 mg/ml), it is poorly absorbable in the GIT, and the long-term oral administration of TX may cause severe GIT disturbances. Topical administration of TX can help in bypassing the GIT adverse effects. Therefore, in the present work, we constructed different pluronic/lecithin organogels (PLOs) for topical delivery of TX. PLO was constructed simply via direct mixing of an aqueous pluronic solution with lecithin solution. The prepared PLO formulations were characterized for their physicochemical properties including pH, drug content, visual inspection, viscosity, and spreadability. Also, the in vitro release and kinetic studies were carried out to investigate the mechanism of drug release. Moreover, the in vivo studies were carried out by investigating the anti-inflammatory and analgesic activities using albino male rats. The results showed that the modified PLOs have good physicochemical properties. The viscosity of the modified gels is a direct proportionality with both lecithin and pluronic concentrations. Also, subsequently, the drug release rate is directly proportional to gel viscosity. Moreover, the in vivo studies showed that the modified PLOs (F19) showed a significant ( < 0.05%) paw edema inhibition and pain analgesia compared with other investigated groups. Also, the results indicated that the increase in dose is accompanied by higher activity and a longer duration of action which extended to 12 h. Hence, the modified PLOs are promising safe candidates or vehicles for effective TX loading with sustained delivery behavior.

A Novel Approach for the Availability and Ocular Delivery of Tenoxicam Potassium: Synthesis, Characterization, and In Vivo Application

Tenoxicam (TX) is a non-steroidal anti-inflammatory agent that can be used to control pain in various ophthalmic lesions like cataracts, refractive surgery, and corneal abrasion. TX has a very slightly aqueous solubility of 0.072 mg/mL resulting in difficulty to be formulated in ophthalmic solutions. This study aims to improve TX solubility by converting it into its potassium salt to achieve a target of 10 mg/mL (1%w/v) concentration of TX in the desired aqueous medium for the formulation of aqueous ophthalmic solutions. The synthesized TX salt was characterized by different evaluation parameters such as solubility studies, ¹H NMR, IR, and elemental analyses. Different TX potassium solutions were formulated at concentrations of 0.5% and 1% w/v using different viscosity-imparting agents. The prepared solutions were characterized for their physicochemical properties including visual inspection, pH, rheological, in vitro release, and kinetic behavior. Also, the formulations were biologically evaluated in vivo using male albino rabbits. The obtained results showed the successful synthesis of TX salt, as indicated by IR and NMR, and elemental analysis. The solubility study showed that the solubility of TX was improved hugely to 18 mg/mL (250-fold). In addition, the results showed that the prepared formulations showed acceptable physicochemical properties. The highest release rate was obtained with formula F1, which contains no viscosity-imparting agents. While as, the lowest release rate was obtained in the case of formula F9, composed of Pluronic F127 (12% w/v). The in vivo results showed that TX optimized ophthalmic solutions F8 and F9 inhibited the redness and edema in an extended or sustained manner.

Clinical study on the efficacy of hepatitis B vaccination in hepatitis C virus related chronic liver diseases in Egypt

BACKGROUND

Chronic hepatitis B (HBV) and C virus (HCV) infections represent significant public health issues internationally. HBV vaccination has high sero-conversion rates in patients with mild to moderate chronic liver disease but has reduced efficacy in advanced stages.

AIM

to evaluate the efficacy of hepatitis B vaccination in HCV-related chronic liver disease and identify possible factors that may contribute to hypo-responsiveness in those patients.

METHODS

Our study was a retrospective observational clinical study carried out at the tropical medicine department. It was conducted on 500 individuals (400 chronic HCV patients and 100 healthy controls). Individuals were divided into 5 groups: A (control group), B (cirrhotic patient not receiving treatment), C (chronic hepatitis patients receiving treatment), D (cirrhotic patients receiving treatment), and E (HCC patients receiving treatment). All individuals were subjected for comprehensive history taking, clinical examination, laboratory investigations, and assessment of anti-HBs titer.

RESULTS

There is an inverse relationship between the level of anti-HBs Abs and the duration of vaccine. Diabetes and presence of cirrhosis have statistically significant relationship with serum anti-HBs Abs titer (P = 0.007). Oral DAAs therapy is associated with reduced response to HBV vaccine (only 31.75% of the patients were protected).

CONCLUSION

HCV infection and its complications significantly impair HBV vaccine response. Levels of anti-HBs Abs decline progressively with increasing duration from the last dose in immunization schedule of HBV vaccine. Diabetes and presence of cirrhosis being the main risk factors for vaccine hypo-responsiveness, also oral DAAs therapy is associated with reduced response to HBV vaccine.

Mitral valve replacement through mini sternotomy after long ECMO course: Case report

INTRODUCTION

Mitral regurgitation (MR) is defined as an abnormal reversal of blood flow from the left ventricle to the left atrium (LA). It is caused by disruption in any part of the mitral valve apparatus. Surgical intervention remains the mainstay of management for severe cases.

CASE SUMMARY

We are reporting a case of pneumonia with severe sepsis, that had a complicated hospital course. The patient developed multi-organ failure. Echocardiography on admission showed severe mitral regurgitation. He required early mechanical ventilation and then Veno-venous Extracorporeal Membrane Oxygenation (VV-ECMO) over 29 days. He might be the first case of Coronavirus Disease 2019 (COVID-19) in our hospital. Mitral valve replacement was done after stabilization of the patient and weaning from the ECMO.

DISCUSSION

Our report demonstrates that the use of a long term VV-ECMO as a bridge for stabilization, facilitates management of the critically ill respiratory failure patient with severe MR and patient outcomes. Still the long-term results and the optimal timing of intervention need more research to define.

CONCLUSION

Our report demonstrates that the use of a long term VV ECMO facilitates management of patients with respiratory failure associated with severe MR. Future studies focusing on stabilizing such patients, might help to define the optimal timing for intervention in these patients and the long-term outcome.

Hydralazine HCl rapidly disintegrating sublingual tablets: simple dosage form of higher bioavailability and enhanced clinical efficacy for potential rapid control on hypertensive preeclampsia

BACKGROUND

Hypertensive disorders are the most common complication in pregnancy which can even lead to maternal mortality. Hydralazine hydrochloride (HHC), a direct-acting vasodilator, is intravenously used as the first-line therapy in controlling hypertension in pregnancy (preeclampsia). It suffers poor oral bioavailability (26%-50%) due to first-pass metabolism.

OBJECTIVE

This work aims for the preparation of HHC rapidly disintegrating sublingual tablets of higher absorption rate, short onset of action, and higher bioavailability for rapid control on blood pressure (BP) in hypertensive emergencies especially preeclampsia.

METHODS

HHC sublingual tablet mixtures were prepared using starch sodium glycolate and Pharmaburst as super disintegrants at three different levels by direct compression and were subjected to full in vitro evaluation; the drug bioavailability from the optimized sublingual tablet formula was assessed in comparison to conventional oral tablets in rabbits, and the clinical efficacy on controlling BP in induced preeclampsia like mouse model was also studied.

RESULTS

The results indicated compatibility of the prepared tablet mixtures, good flow, and acceptable mechanical strength. Sublingual tablet formula containing Pharmaburst (7%) that showed fastest disintegration (21 seconds) and 100% drug release within 5 minutes was selected for further bioavailability and pharmacodynamic studies. The drug bioavailability was significantly increased with C max = 28.2767±4.61 µg/mL, AUC(0-α) = 52.85±3.18 µg.h/mL, and T max = 0.33±0.011 hour in comparison to 18.0633±23.2 µg/mL, 33.18±5.18 µg⋅h/mL, and 0.75±0.025 hour for conventional oral tablets. Results of pharmacodynamic studies proved significant rapid control on both systolic and diastolic BP to normal values within only 30 minutes without any significant difference from intravenous data.

CONCLUSION

These results confirm the suitability of the prepared HHC sublingual tablets for use in rapid control on hypertensive crisis especially in pregnant women as an alternate to parenteral administration.

In VitroandIn VivoCartilage Engineering Using a Combination of Chondrocyte-Seeded Long-Term Stable Fibrin Gels and Polycaprolactone-Based Polyurethane Scaffolds

The use of either a hydrogel or a solid polymeric scaffold alone is often associated with distinct drawbacks in many tissue engineering applications. Therefore, in this study, we investigated the potential of a combination of long-term stable fibrin gels and polyurethane scaffolds for cartilage engineering. Primary bovine chondrocytes were suspended in fibrin gel and subsequently injected into a polycaprolactone-based polyurethane scaffold. Cells were homogeneously distributed within this composite system and produced high amounts of cartilage-specific extracellular matrix (ECM) components, namely glycosaminoglycans (GAGs) and collagen type II, within 4 weeks of in vitro culture. In contrast, cells seeded directly onto the scaffold without fibrin resulted in a lower seeding efficiency and distinctly less homogeneous matrix distribution. Cell-fibrin-scaffold constructs implanted into the back of nude mice promoted the formation of adequate engineered cartilaginous tissue within the scaffold after 1, 3, and 6 months in vivo, containing evenly distributed ECM components, such as GAGs and collagen. Again, in constructs seeded without fibrin, histology showed an inhomogeneous and, thus, not adequate ECM distribution compared to seeding with fibrin, even after 6 months in vivo. Strikingly, a precultivation for 1 week in vitro elicited similar results in vivo compared to precultivation for 4 weeks; that is, a precultivation for longer than 1 week did not enhance tissue development. The presented composite system is suggested as a promising alternative toward clinical application of engineered cartilaginous tissue for plastic and reconstructive surgery.

Lipidic implants for controlled release of bioactive insulin: effects on cartilage engineered in vitro

Controlled release systems for growth factors and morphogens are potentially powerful tools for the engineering or the treatment of living tissues. However, due to possible instabilities of the protein during manufacture, storage, and release, in the development of new release systems it is paramount to investigate into the maintenance of bioactivity of the protein. Within this study, recently developed protein releasing lipid matrix cylinders of 2 mm diameter and 2 mm height made from glycerol tripalmitate were manufactured in a compression process without further additives. Insulin in different concentrations (0.2%, 1%, and 2%) served as model protein. The bioactivity of the protein released from the matrices was investigated in a long-term cartilage engineering culture for up to four weeks; additionally, the release profiles were determined using ELISA. Insulin released from the matrices increased the wet weights of the cartilaginous cell-polymer constructs (up to 3.2-fold), the amount of GAG and collagen in the constructs (up to 2.4-fold and 3.2-fold, respectively) and the GAG and collagen content per cell (1.8-fold and 2.5-fold, respectively), compared to the control. The dose-dependent effects on tissue development correlated well with release profiles from the matrices with different insulin loading. In conclusion, the lipid matrices, preserving the bioactivity of incorporated and released protein, are suggested as a suitable carrier system for use in tissue engineering or for the localized treatment of tissues with highly potent protein drugs such as used in the therapy of brain cancer or neurodegenerative CNS diseases.

5-HT1B receptors modulate release of [3H]dopamine from rat striatal synaptosomes: further evidence using 5-HT moduline, polyclonal 5-HT1B receptor antibodies and 5-HT1B receptor knock-out mice

In previous paper based on classical pharmacological tools, we identified a Gi protein-coupled presynaptic 5-hydroxytryptamine (5-HT) 1B receptor causing inhibition of dopamine (DA) release in rat striatal synaptosomes. It was the aim of the present study to further explore this receptor, using 5-HT moduline, a polyclonal antibody directed against 5-HT1B receptors and 5-HT1B receptor knock-out mice. Preincubation of rat striatal synaptosomes with 5-HT moduline (0.1, 1, or 10 microM) significantly reduced the inhibitory effect of CP93,129, a selective rat 5-HT1B receptor agonist, on K+-evoked overflow of [3H]DA in a non-competitive manner: 5-HT moduline did not modify the IC50 of CP93,129, but concentration-dependently reduced the maximal inhibitory effect. Preincubation of rat striatal synaptosomes with a specific polyclonal 5-HT1B receptor antibody also resulted in a significant attenuation of the inhibitory effect of CP93,129 on K+-evoked overflow of [3H]DA. In female 129/Sv wild-type mice, CP93,129 and 5-carboxyamidotryptamine maleate (5-CT), a non-selective 5-HT1B receptor agonist, inhibited the K+-evoked [3H]DA overflow in a concentration-dependent manner. Sumatriptan, a selective rat 5-HT1D receptor agonist, did not modify the overflow of [3H]DA. SB224289, a selective 5-HT1B receptor antagonist, abolished the inhibitory effects of CP93,129 and 5-CT. The inhibitory effects of CP93,129 and 5-CT were absent in synaptosomes from 5-HT1B receptor knockout mice. No compensatory inhibition effect in mutant mice was observed using sumatriptan. In conclusion, the results show that a non-competitive antagonist of the 5-HT1B receptor concentration-dependently decreases the maximal inhibitory effect of a 5-HT1B receptor agonist on the synaptosomal K+-evoked release of [3H]DA in striatum. Moreover, a specific antibody raised against the receptor and particularly directed against a region of the receptor protein involved in signal transduction, namely the coupling with the G-protein, also antagonizes the inhibitory effect of the stimulation of 5-HT1B receptor on the release of [3H]DA. Ultimately the disruption of 5-HT1B receptor gene in 5-HT1B knock-out mice leads to a total suppression of the effect of 5-HT1B receptor agonists on [3H]DA release. These observations further support our previous observations using selective agonists/antagonists, indicating that 5-HT1B receptors control the release of neuronal DA as presynaptic heteroreceptors.

Differential sensitivity of 5-HT1B auto and heteroreceptors

The effect of the native and rodent-selective 5-HT1B receptor agonists (5-hydroxytryptamine (5-HT) and CP93,129) on the K+-evoked overflows of [3H]5-HT, [3H]dopamine (DA) and [3H]acetylcholine (ACh) was studied in synaptosome preparations obtained from rat brain striatum or hippocampus loaded with radiolabeled neurotransmitter. The aim of the study was to compare the different potencies of the specific 5-HT1B receptor agonists to stimulate the auto and heteroreceptors and to modulate the different neurotransmitter release. Results show that under the same experimental conditions, 5-HT and CP93,129 exhibited significantly higher potencies in inhibiting the K+-evoked overflow of [3H]5-HT from synaptosomes of rat striatum (IC50=2.0+/-1.8 nM and 20.5+/-3.1 nM, respectively) than in inhibiting the K+-evoked overflow of [3H]DA from synaptosomes of the same cerebral region (IC50= 0.8+/-0.2 microM and 1.8+/-0.4 microM, respectively), or [3H]ACh from synaptosomes of hippocampus (IC50=1.7+/-0.8 microM for CP93,129). The inhibitory effects of the 5-HT1B receptor agonists on [3H] K+-overflows were antagonized by the selective 5-HT1B receptor antagonist (SB224289), further indicating that the observed effects were 5-HT1B receptor specific. Sumatriptan, a selective r5-HT1D receptor agonist, did not show any significant effect on the K+-overflow of [3H]5-HT in the range of concentrations (10(-10) to 10(-6) M), and did not affect the K+ overflow of [3H]DA or [3H]ACh at concentrations (10(-9) to 10(-4) M), which exclude the involvement of 5-HT1D receptors. These inhibitory effects of the 5-HT1B receptor agonists were highly attenuated by pertussis toxin in the three systems studied, suggesting the involvement of Gi/Go-proteins in the transduction mechanism pathway of the receptor generated signal. In conclusion, these results suggest that 5-HT1B heteroreceptors located on dopaminergic and cholinergic terminals exhibit a lower sensitivity to 5-HT1B receptor agonist and antagonist than do 5-HT1B autoreceptors. The observed difference in functional sensitivities of 5-HT1B auto- and heteroreceptors may represent important consequences in the physiological control of the release of serotonin versus that of other neurotransmitters.

5-HT1B receptors modulate release of [3H]dopamine from rat striatal synaptosomes

The effect of the selective r5-HT1B agonist 3-(1,2,5,6-tetrahydro)-4-pyridil-5-pyrrolo [3,2-b] pyril-5-one (CP93,129) on the K(+)-evoked overflow of [3H]dopamine was studied in rat striatal synaptosomes loaded with [3H]dopamine. The aim of the study was to investigate the participation of 5-HT1B receptors in the serotonergic modulation of striatal dopaminergic transmission. The Ca2(+)-dependent, tetrodotoxin-resistant K(+)-evoked overflow of [3H]dopamine was inhibited by CP93,129 (0.01-100 microM) in a concentration-dependent manner (IC50=1.8 microM; maximal inhibition by 35.5% of control). [+/-]8-OH-DPAT, a 5-HT(1A) receptor agonist, [+/-]DOI, a 5-HT2 receptor agonist, and 2-methyl-5-hydroxytryptamine, a 5-HT3 receptor agonist, at concentrations ranging from 0.01 microM to 100 microM did not show any significant effect. Neither ketanserin (1 microM and 5 microM), a selective 5-HT2/5-HT1D receptor antagonist, nor ondansetron (1 microM), a 5-HT3 receptor antagonist, changed the inhibitory effect of CP93,129. SB224289, GR55562, GR127935, isamoltane and metergoline, selective and non-selective 5-HT1B receptor antagonists, in contrast, used at a concentration of 1 microM, antagonized the inhibitory effect of CP93,129 (3 microM and 10 microM). SB224289, a selective 5-HT1B receptor antagonist, inhibited the effect of CP93,129 in a concentration-dependent manner; the calculated K(i) value was 1.8 nM. Our results indicate that in rat striatal axon terminals the K(+)-evoked release of dopamine is regulated by the presynaptic 5-HT1B heteroreceptors.

Mapping of 5-HT-moduline binding sites in guinea-pig brain by film and digital autoradiography

5-HT-moduline is a cerebral tetrapeptide [Leu-Ser-Ala-Leu] that was recently isolated from bovine brain tissue and shown to interact specifically with 5-HT1B receptors, particularly in rodents. The pharmacological properties of 5-HT1B receptors in rodents are different from those in other species. In order to better understand the role of this peptide in non-rodent species, we determined the distribution of 5-HT-moduline binding sites in guinea-pig brain using both the film autoradiography and digital autoradiography with a newly developed high resolution beta-imaging techniques. We found that 5-HT-moduline binding sites were expressed in various brain regions. Quantitative analysis showed that densities of binding sites were similar to those observed previously in rat brain. Regions with the highest labelling included cortex, septum, hippocampus and some regions of basal ganglia. Our results extend previous data and show that 5-HT-moduline interacts with the two forms of 5-HT1B receptors that are distinct pharmacologically. By this interaction, 5-HT-moduline may play an important role in regulating the functional activity of 5-HT1B receptors, thereby contributes to the pathophysiology of serotonergic transmission.

Sub-chronic cold stress reduces 5-HT1A receptor responsiveness in the old but not in the young rat

The inhibitory effect of the prototypical 5-hydroxytryptamine (5-HT)1A receptor agonist 8-hydroxy-2-(di-n-propyl amino)tetraline (8-OH-DPAT) on forskolin-stimulated adenylyl cyclase activity, has been examined as an index of the functional activity of 5-HT1A receptors in the hippocampus of young (3 months) and old (18 months) rats exposed during 24 h or 5 days to cold. In both young and old rats exposed to cold stress during 24 h, there was a reduction in the potency (EC50) and/or the maximal inhibitory effect (Emax) of 8-OH-DPAT in reducing forskolin-induced cAMP accumulation. The properties of the hippocampal 5-HT1A sites labelled by [3H]8-OH-DPAT were not affected by these stressful conditions. Moreover, while the sensitivity of 5-HT1A receptors to 8-OH-DPAT in young rats returned to control values after 5 days of cold exposure, old rats still exhibited a significant desensitization of 5-HT1A receptors as compared to naive animals. These results point out the capacity of young but not of old rats to adapt to the aversive effects of a subchronic stressor.

Stress-induced 5-HT1A receptor desensitization: protective effects of Ginkgo biloba extract (EGb 761)

The effects of sub-chronic cold stress on the functioning of hippocampal 5-HT1A receptors in old isolated rats and the possible protective effects of Ginkgo biloba extract (EGb 761) were investigated. Cold exposure during five days, produced a significant reduction of the inhibitory effect of 8-hydroxy-2-(di-n-propylamino)tetraline (8-OH-DPAT) on forskolin-stimulated adenylyl cyclase activity. In contrast, neither the affinity nor the density of hippocampal [3H]8-OH-DPAT binding sites were affected indicating that the reduced sensitivity of 5-HT1A receptors induced by stress is probably due to a modification of their coupling mechanisms to adenylyl cyclase. The stress-induced desensitization of 5-HT1A receptors was prevented by the administration of EGb 761 (50 mg/kg per os/14 days). These results clearly indicate that 5-HT1A receptors are desensitized by stress and point out the reduced capacity of old rats to cope with the adverse effects of a chronic stressor. EGb 761 appears to restore the age-related decreased capacity to adapt to a chronic stressor.

Regional distribution of 3-O-methyl-DOPA in the cortex and subcortical structures in the rat: effect of aging

Dihydroxyphenylalanine (DOPA) and its metabolite 3-O-methyl-DOPA (3-OMDOPA) have been identified as normal constituents in blood, CSF and brain in human and several animal species. In the present study, we report results of 3-OMDOPA measurements in seven cortical areas, hippocampus and striatum of young (3-month-old), middle aged (10-month-old) and aged (27-month-old) rats. 3-OMDOPA was identified in all the areas considered. Regional differences were observed, with the highest levels being found in the hippocampus and the somatomotor and pyriform cortex. A marked increase in the level of 3-OMDOPA was observed in all the cortical areas and in the hippocampus of aged rats. In contrast, this level remained unchanged in the striatum. These modifications were compared to those observed in the levels of dopamine (DA) in the same areas.