Latanoprost niosomes as a sustained release ocular delivery system for the management of glaucoma.

Objective: Glaucoma is a leading cause of irreversible blindness worldwide. Whereas latanoprost is one of the most effective drugs in glaucoma treatment, its eye drops need frequent application leading to lack of patient adherence. This study aimed to develop a patient-friendly niosome-in-gel system for the sustained ocular delivery of latanoprost.Methods: Niosomes were prepared by the reverse-phase evaporation technique and optimized for different formulation parameters, such as cholesterol/surfactant and drug/surfactant ratios. Selected niosomal formulations were incorporated into different gels and their viscosity and drug release kinetics were evaluated. Optimal niosomal gel was evaluated in vivo in rabbits' eyes for irritation potential and ability to reduce intraocular pressure.Results: FT-IR studies showed that there were nonspecific interactions between latanoprost and different niosomal components leading to drug encapsulation efficiency ≥88%. Latanoprost encapsulation efficiency increased with the drug/surfactant ratio and encapsulation efficiency ∼98% was obtained at a ratio of 50%. Pluronic® F127 had the best ability to sustain drug release from the niosomes. In rabbits' eyes, this gel was free of toxic and irritant effects and reduced intraocular pressure over a period of three days, which was significantly longer than that of commercial latanoprost eye drops.Conclusion: Latanoprost niosomal Pluronic® F127 gel may find applications in glaucoma management.

Pharmacokinetic studies of naproxen amides of some amino acid esters with promising colorectal cancer chemopreventive activity.

Naproxen (nap) is belonging to Non-steriodal anti-inflammatory drugs (NSAIDs) group of drugs that characterized by their free carboxylic group. The therapeutic activity of nap is usually accompanied by GI untoward side effects. Recently synthesized naproxen amides of some amino acid esters prodrugs to mask the free carboxylic group were reported. Those prodrugs showed a promising colorectal cancer chemopreventive activity. The current study aims to investigate the fate and hydrolysis of the prodrugs kinetically in different pH conditions, simulated gastric and intestinal fluids with pHs of 1.2, 5.5 and 7.4 in vitro at 37 °C. The effect of enzymes on the hydrolysis of prodrugs was also studied through incubation of these prodrugs at 37 °C in human plasma and rat liver homogenates. The pharmacokinetic parameters of selected prodrugs and the liberated nap were studied after oral and intraperitoneal administration in male wistar rats. The results showed the hydrolysis of naproxen amides of amino acid esters to nap through two steps first by degradation of the ester moiety to form the amide of nap with amino acid and the second was through the degradation of the amide link to liberate nap. The two reactions were followed and studied kinetically where K1 and K2 (rate constants of degradation) is reported. The hydrolysis of prodrugs was faster in liver homogenates than in plasma. The relative bioavailability of the liberated nap in vivo was higher in case of prodrug containing ethyl glycinate moiety than that occupied l-valine ethyl ester moiety. Each of nap. prodrugs containing ethyl glycinate and l-valine ethyl ester moieties appears promising in liberating nap, decreasing direct GI side effect and consequently their colorectal cancer chemopreventive activity.

Phenotypic and genotypic characterization of erythromycin-resistant Staphylococcus aureus isolated from bovine subclinical mastitis in Egypt.

Background and Aim: Subclinical mastitis (SCM) caused by erythromycin-resistant Staphylococcus aureus is a significant disease in lactating animals. Therefore, it is crucial to understand the genetic factors contributing to erythromycin resistance in S. aureus. This study aimed to estimate the prevalence of S. aureus in milk from subclinical mastitic cattle and buffaloes and tank milk samples as identified by probe-based real-time polymerase chain reaction (PCR) and the genotypic assessment of macrolide and erythromycin resistance profiles, as well as to analyze the phylogenetic relatedness of our local isolates of S. aureus. Materials and Methods: In total, 285 milk samples were analyzed using the California mastitis test to detect SCM. Milk samples were cultured on different specific Staphylococcus media. The presence of S. aureus was confirmed by Gram staining, the catalase and coagulase tests, the detection of hemolytic activity, DNase agar testing, and biofilm activity in Congo red medium. The genotypic identification of S. aureus (nuc) was performed. The determinants of erythromycin (ermA, ermB, ermC, and ermT) and macrolide resistance (msrA) were screened in all isolates. DNA sequencing of our local isolates of S. aureus was used to analyze their phylogenetic relatedness. Moreover, histopathological examination of tissue specimens of mammary gland was performed. Results: The S. aureus positivity rates were 36.4%, 48.8%, and 63.6% in cattle, buffalo, and bulk tank milk, respectively. Probe-based real-time PCR molecularly confirmed all 62 S. aureus isolates. Thirty-one isolates were subjected to PCR to create profiles of their genotypic erythromycin resistance. ermA, ermB, ermC, and ermT were present in 5 (8%), 26 (41.9%), 18 (29%), and 15 (24.1%) S. aureus isolates, respectively. Moreover, msrA was found in three (4.8%) strains. Eight PCR products were produced using standard PCR for DNA sequencing. Multiple sequence alignment, phylogenetic tree construction, and analysis of nuc in S. aureus revealed a high degree of homology (100%) with S. aureus strains isolated from milk in cases of bovine mastitis in India and Kenya. Histological analysis of udder tissues revealed extensive aggregation of mononuclear inflammatory cells in the interstitial connective tissue, primarily lymphocytes, and macrophages. Conclusion: This study showed a high prevalence of erythromycin resistance in S. aureus isolates. This information is vital for controlling mastitis and the spread of resistance genes between bacterial strains and hosts. Moreover, the probe-based real-time PCR approach is helpful for the rapid screening of S. aureus isolates and the consequent efficient treatment and control of S. aureus mastitis.

Dogs as a source for the spreading of enteric parasites including zoonotic ones in Giza Province, Egypt.

To investigate the impact of domestic and stray dogs on the transmission of zoonotic and other parasites to humans in contact with them, fecal samples were collected from 80 domestic dogs that presented at a clinic with health disturbances and 220 randomly selected stray dogs housed in shelters. The parasitological examination of these samples revealed infection by six zoonotic and four non-zoonotic parasites in varying percentages. The zoonotic parasites included Ancylostoma caninum, Toxocara canis, Dipylidium caninum, Echinococcus granulosus, Cryptosporidium species, and Giardia cysts and trophozoites. The other parasites included Toxascaris leonina, Trichuris vulpis, Taenia species eggs, and Isospora canis oocysts. The infection rate was higher in stray dogs (60%) than in domestic dogs (40%). Infected dogs in both groups were generally unhealthy, with poor body condition recorded in 13.8% of domestic dogs and 63.6% of stray dogs. The infection rate was higher (92%) among shelter workers than among domestic dog owners (66.7%). Giardia assemblages A and D from dogs and assemblage A from humans, as well as two isolates of Cryptosporidium canis (C. canis), one from dogs and the other from humans, were submitted in the GenBank with the accession numbers OQ870443, OQ870444, and OQ919265 for Giardia and OQ917532 & OQ915519 for C. canis of dogs & human, respectively. In conclusion, domestic and stray dogs play an essential role in transmitting zoonotic parasites to humans in contact with them, and regular deworming and strict hygienic measures are recommended to minimize their impact on human health.

Current trends in pharmaceutical treatment of dry eye disease: A review.

Dry eye disease (DED), keratoconjunctivitis sicca or dysfunctional tear syndrome, is the most prevalent ophthalmic disease which affects a substantial segment of people worldwide with increasing frequency. It is considered a multifactorial disease of the ocular surface and tear film, characterized by a variation of signs and symptoms. The symptoms range from mild to severe itching, burning, irritation, eye fatigue, and ocular inflammation that may lead to potential damage to the cornea, conjunctiva and even vision loss. Correspondingly, depending on the different manifestations and pathophysiology, the treatment must be tailored specifically to each patient by targeting the specific mechanisms implicated in their disease. Currently, there are several medical products and techniques available or under investigation for the treatment of DED. The present article focused on the pathophysiology of DED, the new diagnostic approach and the recently developed drug delivery systems or devices reducing the progress of the disease and treating the causes.

Celecoxib-Loaded Solid Lipid Nanoparticles for Colon Delivery: Formulation Optimization and In Vitro Assessment of Anti-Cancer Activity.

This work aimed to optimize a celecoxib (CXB)-loaded solid lipid nanoparticles (SLN) colon delivery system for the enhancement of anticancer activity. An ultrasonic melt-emulsification method was employed in this work for the preparation of SLN. The physical attributes were characterized for their particle sizes, charges, morphology, and entrapment efficiency (%EE), in addition to DSC and FTIR. The in vitro drug release profiles were evaluated, and the anticancer activity was examined utilizing an MTT assay in three cancer cell lines: the colon cancer HT29, medulloblastoma Daoy, and hepatocellular carcinoma HepG2 cells. All of the prepared SLN formulations had nanoscale particle sizes ranging from 238 nm to 757 nm. High zeta-potential values (mv) within -30 s mv were reported. The %EE was in the range 86.76-96.6%. The amorphous nature of the SLN-entrapped CXB was confirmed from SLN DSC thermograms. The in vitro release profile revealed a slow constant rate of release with no burst release, which is unusual for SLN. Both the F9 and F14 demonstrated almost complete CXB release within 24 h, with only 25% completed within the first 5 h. F9 caused a significant percentage of cell death in the three cancer cell lines tested after 24 h of incubation and maintained this effect for 72 h. The prepared CXB-loaded SLN exhibited unique properties such as slow release with no burst and a high %EE. The anticancer activity of one formulation was extremely significant in all tested cancer cell lines at all incubation times, which is very promising.

The use of spray-drying to enhance celecoxib solubility.

The present research investigates the enhancement of the dissolution rate of celecoxib by using spray-drying to prepare a solid dispersion with various polymers, namely Kollicoat IR® (Kollicoat), polyvinyl alcohol (PVA) 22000, or polyethylene glycol 6000 (PEG). The investigated drug-to-polymer mass ratios were 1:1, 1:2, and 1:4 by weight. Hydroalcoholic or methylene chloride solvent systems were used. The obtained yields ranged from 65% to 78%, whereas the entrapment efficiencies were between 68% and 82%. The results revealed an increase in the dissolution rate of the prepared particles up to 200% within 20 min. The prepared particles were investigated using differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The increased dissolution rate was attributed to hydrogen bond formation between celecoxib and each polymer together with the reduced size of the formed particles offering a greater overall surface area. It was concluded that spray-drying may be considered a successful one-step technique to improve the dissolution rate of celecoxib when using Kollicoat, PVA, or PEG as the carrier polymer.

Isolation, identification and virulence determinants of Streptococcus agalactiae from bovine subclinical mastitis in Egypt.

INTRODUCTION: This study aimed to investigate the prevalence of contagious mastitis caused by Streptococcus agalctiae (S. agalactiae) in cattle from households and small-scale dairy farms in Egypt. Molecular characterization of S.agalactiae isolates was described including the genetic determinants of virulence to assess the genetic variation in isolated strains of S. agalactiae. METHODOLOGY: Three hundred and sixty milk samples were collected from 90 apparently healthy dairy cows randomly selected from household and small-scale dairy farms were examined by Somatic Cell Count (SCC) as an indicator for subclinical mastitis. S.agalactiae isolates were bacteriologically and molecularly identified followed by identification of virulence genes using PCR. RESULTS: A total of 172 milk samples (47.77%) were positive with SCC > 200×103/ml. Bacteriological examination of the positive SCC milk samples revealed that 28 (16.28%) of the isolates were S.agalactiae. Molecular examination using PCR confirmed only 22 isolates of S. agalactiae (12.8%). Moreover, we used the pattern of virulence genes to address the genetic variation of S. agalactiae strains isolated from cases of contagious mastitis in cattle in Egypt. Virulence genes hylB, cylE, iagA, and bac were determined in 100%, 68.2%, 13.6% and 100% of isolates respectively. CONCLUSIONS: The use of molecular methods for the identification of the causative agent in mastitis confirmed that, in Egypt, Streptococcus agalactiae is considered as one of the predominant infectious agents among contagious mastitis causing pathogens. The pattern of virulence genes presented the genetic diversity of highly virulent S. agalactiae strains isolated from cases of contagious mastitis in cattle in Egypt.

Preparation and investigation of acetyl salicylic acid-caffeine complex for rectal administration.

An acetyl salicylic acid-caffeine complex was prepared and evaluated for the potential use in rectal administration. The results revealed the formation of a complex between acetyl salicylic acid and caffeine in a 1:1 molar ratio by a charge transfer mechanism. The effects of acetyl salicylic acid and complex on the rectal tissues showed destruction in the mucosal epithelium in case of acetyl salicylic acid; however, no change in the rectal tissues was noticed upon the administration of the complex. The effect of suppository bases on the release of the complex was studied using Witepsol H15 as fatty base and polyethylene glycols (PEG) 1000 and 4000 as a water soluble suppository base. The release profiles of acetyl salicylic acid and the complex were faster from PEG than from that of Witepsol H15. The percent release for the complex and acetyl salicylic acid from PEG base were 45.8, and 34.9%, respectively. However, it was 8.7 and 7.8%, respectively, from Witepsol H15 fatty base. The release kinetic was found to follow the non-Fickian diffusion model for complex from the suppository bases. It was concluded that acetyl salicylic acid caffeine complex can be used safely for rectal administration.

Preparation and investigation of acetyl salicylic acid-caffeine complex for rectal administration.

An acetyl salicylic acid-caffeine complex was prepared and evaluated for the potential use in rectal administration. The results revealed the formation of a complex between acetyl salicylic acid and caffeine in a 1:1 molar ratio by a charge transfer mechanism. The effects of acetyl salicylic acid and complex on the rectal tissues showed destruction in the mucosal epithelium in case of acetyl salicylic acid; however, no change in the rectal tissues was noticed upon the administration of the complex. The effect of suppository bases on the release of the complex was studied using Witepsol H15 as fatty base and polyethylene glycols (PEG) 1000 and 4000 as a water soluble suppository base. The release profiles of acetyl salicylic acid and the complex were faster from PEG than from that of Witepsol H15. The percent release for the complex and acetyl salicylic acid from PEG base were 45.8, and 34.9%, respectively. However, it was 8.7 and 7.8%, respectively, from Witepsol H15 fatty base. The release kinetic was found to follow the non-Fickian diffusion model for complex from the suppository bases. It was concluded that acetyl salicylic acid caffeine complex can be used safely for rectal administration.