Metallo-ß-lactamase and AmpC genes in Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa isolates from abattoir and poultry origin in Nigeria.

BACKGROUND: Gram-negative bacteria (GNB) including Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae represent the most relevant reservoir of resistance genes such as metallo-ß-lactamase (MBL) and AmpC genes that give them the undue advantage to resist antimicrobial onslaught. This study aimed to investigate the occurrence of MBL (blaIMP-1, blaIMP-2, blaVIM-1, blaVIM-2) and AmpC (blaFOX, blaDHA, blaCMY, blaACC) resistance genes in aforementioned GNB collected from abattoir and poultry sources in Nigeria. RESULTS: In total, 370 isolates were collected from abattoir tables (n = 130), anal region of cows (n = 120), and the cloacae of poultry birds (n = 120). The test isolates showed high rate of resistance to cephalosporins and carbapenems. The MBLs were phenotypically detected in 22 E. coli, 22 P. aeruginosa, and 18 K. pneumoniae isolates using combined disc test (CDT). However, only 11 E. coli, 24 P. aeruginosa, and 18 Klebsiella pneumoniae isolates were phenotypically confirmed to be AmpC producers using cefoxitin-cloxacillin double disk synergy test (CC-DDST). MBL encoding genes (particularly the blaIMP-1 genes and blaIMP-2 genes) were detected by polymerase chain reaction (PCR) in 12 (54.6%) E. coli, 15 (83.3%) K. pneumoniae, and 16 (72.7%) P. aeruginosa isolates. AmpC genes (particularly the blaCMY genes and blaFOX genes) were found in a total of 5 (29.4%) E. coli isolates, 5 (27.8%) isolates of K. pneumoniae, and 10 (41.7%) isolates of P. aeruginosa. CONCLUSIONS: Our study showed the circulation of MBL and AmpC genes in GNB from abattoir and poultry origin in Nigeria. Adoption of regular control policies is necessary to reduce the spread of these species as soon as possible, especially in poultry and slaughterhouses.

Nanovesicle Formulation Enhances Anti-inflammatory Property and Safe Use of Piroxicam.

BACKGROUND: Enhanced utilization of certain drugs may be possible through the development of alternative delivery forms. It has been observed that NSAIDs have adverse gastrointestinal tract effects such as irritation and ulceration during anti-inflammatory therapy. This challenge may be overcome through nano topical formulations. OBJECTIVE: This study aimed to explore the potentials of a transdermal nanovesicular formulation for safe and enhanced delivery of piroxicam (PRX), a poorly water-soluble NSAID. METHODS: Preformulation studies were conducted using DSC and FTIR. Ethosomal nanovesicular carrier (ENVC) was prepared by thin-film deposition technique using Phospholipon® 90 H (P90H) and ethanol and then converted into gel form. The formulation was characterized using a commercial PRX gel as control. Permeation studies were conducted using rat skin and Franz diffusion cell. Samples were assayed spectrophotometrically, and the obtained data was analyzed by ANOVA using GraphPad Prism software. RESULTS: The preformulation studies showed compatibility between PRX and P90H. Spherical vesicles of mean size 343.1 ± 5.9 nm, and polydispersity index 0.510 were produced, which remained stable for over 2 years. The optimized formulation (PE30) exhibited pseudoplastic flow, indicating good consistency. The rate of permeation increased with time in the following order: PE30 > Commercial, with significant difference (p< 0.05). It also showed higher inhibition of inflammation (71.92 ± 9.67%) than the reference (64.12 ± 7.92%). CONCLUSION: ENVC gel of PRX was formulated. It showed potentials for enhanced transdermal delivery and anti-inflammatory activity relative to the reference. This may be further developed as a safe alternative to the oral form.

Evaluation of Chitosan-Microcrystalline Cellulose Blends as Direct Compression Excipients.

This study was aimed at evaluating chitosan-microcrystalline cellulose blends as direct compression excipients. Crab shell chitosan, α-lactose monohydrate, and microcrystalline cellulose powders were characterized. Blends of the microcrystalline cellulose and chitosan in ratios 9 : 1, 4 : 1, 2 : 1, and 1 : 1 as direct compression excipients were made to constitute 60% of metronidazole tablets. Similar tablets containing blends of the microcrystalline cellulose and α-lactose monohydrate as well as those containing pure microcrystalline cellulose were also produced. The compact density, tensile strength, porosity, disintegration time, and dissolution rate of tablets were determined. Chitosan had higher moisture content (7.66%) and higher moisture sorption capacity (1.33%) compared to microcrystalline cellulose and lactose. It also showed better flow properties (Carr's index of 18.9% and Hausner's ratio of 1.23). Compact density of tablets increased but tensile strength decreased with increase in the proportion of chitosan in the binary mixtures. In contrast to lactose, the disintegration time increased and the dissolution rate decreased with increase in the proportion of chitosan. This study has shown that chitosan promotes flowability of powder mix and rapid disintegration of tablet. However, incorporation of equal proportions of microcrystalline cellulose and chitosan leads to production of extended-release tablet. Therefore, chitosan promotes tablet disintegration at low concentration and enables extended-release at higher concentration.

Thermochemical Properties of Hydrophilic Polymers from Cashew and Khaya Exudates and Their Implications on Drug Delivery.

Characterization of a polymer is essential for determining its suitability for a particular purpose. Thermochemical properties of cashew gum (CSG) extracted from exudates of Anacardium occidentale L. and khaya gum (KYG) extracted from exudates of Khaya senegalensis were determined and compared with those of acacia gum BP (ACG). The polymers were subjected to different thermal and chemical analyses. Exudates of CSG contained higher amount of hydrophilic polymer. The pH of 2% w/v gum dispersions was in the order KYG < CSG < ACG. Calcium was the predominant ion in CSG while potassium was predominant in KYG. The FTIR spectra of CSG and KYG were similar and slightly different from that of ACG. Acacia and khaya gums exhibited the same thermal behaviour which is different from that of CSG. X-ray diffraction revealed that the three gums are the same type of polymer, the major difference being the concentration of metal ions. This work suggests the application of cashew gum for formulation of basic and oxidizable drugs while using khaya gum for acidic drugs.

Anti-trypanosomal activity of nigerian plants and their constituents.

African trypanosomiasis is a vector-borne parasitic disease causing serious risks to the lives of about 60 million people and 48 million cattle globally. Nigerian medicinal plants are known to contain a large variety of chemical structures and some of the plant extracts have been screened for antitrypanosomal activity, in the search for potential new drugs against the illness. We surveyed the literatures on plants and plant-derived products with antitrypanosomal activity from Nigerian flora published from 1990 to 2014. About 90 plants were identified, with 54 compounds as potential active agents and presented by plant families in alphabetical order. This review indicates that the Nigerian flora may be suitable as a starting point in searching for new and more efficient trypanocidal molecules.

Immunomodulatory and immunorestorative activities of ß-D-glucan-rich extract and polysaccharide fraction of mushroom, Pleurutus tuberregium.

CONTEXT: Some edible mushrooms are reputed to possess useful medicinal properties which are related to their ability to modulate the protective responses of the immune system. OBJECTIVE: This study explored the immunomodulatory and immunorestorative properties of a hot aqueous extract (APTR) and of a ß-d-glucan-enriched polysaccharide fraction (BGP) of a local oyster mushroom Pleurutus tuberregium (Fr.) Singer (Pleurotaceae). MATERIALS AND METHODS: Immunomodulatory activities were investigated by assessing specific and none-specific immune responses in immunocompetent and immunosuppressed mice; as well as in vitro in culture of RAW264.7 macrophages stimulated with BGP. RESULTS: In a homologous prime-boost immunization schedule, oral supplementation with APTR (100, 200, or 400 mg/kg) and BGP (100 or 200 mg/kg) resulted in significantly higher titers of total IgG, IgG1, and IgG2a by as much as 2-4-folds compared with the levels in untreated control mice. The mean hemagglutination (HA) titer in immunized mice that were treated with dexamethasone (DEX; 5 mg/kg) was significantly (p < 0.05) lower than the titer in groups that did not receive dexamethasone; however, short-term alternate day administration of APTR (200 mg/kg) to mice that had been immunosuppressed with 5 mg DEX/kg produced significant increases in secondary anti-SRBC antibody compared with the mean titer of mice immunized and treated with DEX alone. In in vitro studies, stimulation of RAW264.7 macrophages with BGP caused significant increases in iNO and TNF-α expression, and phagocytic functions of the cell. CONCLUSION: Taken together, the results of these studies showed that P. tuberregium imparts immunostimulatory and immunorestorative effects that could be explained, in part, by the actions of its ß-d-glucan constituent(s) on macrophages.

Molecular modeling of potential anticancer agents from African medicinal plants.

Naturally occurring anticancer compounds represent about half of the chemotherapeutic drugs which have been put in the market against cancer until date. Computer-based or in silico virtual screening methods are often used in lead/hit discovery protocols. In this study, the "drug-likeness" of ~400 compounds from African medicinal plants that have shown in vitro and/or in vivo anticancer, cytotoxic, and antiproliferative activities has been explored. To verify potential binding to anticancer drug targets, the interactions between the compounds and 14 selected targets have been analyzed by in silico modeling. Docking and binding affinity calculations were carried out, in comparison with known anticancer agents comprising ~1,500 published naturally occurring plant-based compounds from around the world. The results reveal that African medicinal plants could represent a good starting point for the discovery of anticancer drugs. The small data set generated (named AfroCancer) has been made available for research groups working on virtual screening.

New direct compression excipient from tigernut starch: physicochemical and functional properties.

Tigernut starch has been isolated and modified by forced retrogradation of the acidic gel by freezing and thawing processes. Relevant physicochemical and functional properties of the new excipient (tigernut starch modified by acid gelation and accelerated (forced) retrogradation (ST(AM))) were evaluated as a direct compression excipient in relation to the native tigernut starch (ST(NA)), intermediate product (tigernut starch modified by acid gelation (ST(A))), and microcrystalline cellulose (MCC). The particle morphology, swelling capacity, moisture sorption, differential scanning calorimeter (DSC) thermographs and X-ray powder diffraction (XRD) patterns, flow, dilution capacity, and tablet disintegration efficiency were evaluated. The particles of ST(NA) were either round or oval in shape, ST(A) were smooth with thick round edges and hollowed center while ST(AM) were long, smooth, and irregularly shaped typically resembling MCC. The DSC thermographs of ST(NA) and MCC showed two endothermic transitions as compared with ST(A) and ST(AM) which showed an endothermic and an exothermic. The moisture uptake, swelling, flow, and dilution capacity of ST(AM) were higher than those of MCC, ST(A), and ST(NA). The XRD pattern and moisture sorption profile of ST(AM) showed similarities and differences with ST(NA), ST(A), and MCC that relate the modification. Acetylsalicylic acid (ASA) tablets containing ST(AM) disintegrated at 3±0.5 min as compared with the tablets containing ST(NA), ST(A), and MCC which disintegrated at 8.5±0.5, 10±0.5, and 58±0.8 min, respectively. The study shows the physicochemical properties of tigernut starch modified by forced retrogradation as well as its potential as an efficient direct compression excipient with enhanced flow and disintegration abilities for tablets production.

Pharmacodynamics of piroxicam from novel solid lipid microparticles formulated with homolipids from Bos indicus.

The dissolution of piroxicam is a limiting step in its bioavailability on account of its hydrophobicity. The objective of this research was to formulate novel solid lipid microparticles (SLMs) based on homolipids (admixtures of tallow fat (TF) and Softisan(®) 142 (SFT) templated with Phospholipon(®) 90G (P90G), a heterolipid for the delivery of piroxicam. Lipid matrices consisting of TF and SFT in ratios of 1:1, 1:2 and 2:1 were templated with the heterolipid, P90G and characterized by differential scanning calorimetry (DSC). The SLMs produced by hot homogenization technique using the matrices were characterized in terms of thermal properties, particle size, morphology, drug encapsulation efficiency, stability studies and in vitro diffusion studies. In vivo pharmacodynamic study was performed using egg albumin- induced pedal edema in rats. The results showed that addition of Softisan(®) 142 improved the drug holding capacity of the micellar solution of 2:1 mixture of TF and SFT. The in vitro diffusion of piroxicam from this SLM showed maximum release of 87.53 % and followed non-Fickian diffusion kinetic mechanism. At dose equivalence of 10 mg, piroxicamloaded SLMs showed superior in vivo anti-inflammatory properties at 3 h than Feldene(®) and the pure drug sample. This study has shown that surface-modified SLMs could confer favourable properties with respect to drug release and antiinflammatory activity on SLMs for the delivery of piroxicam, thus encouraging further development of the formulations.

Biodegradable microspheres based on gelatin-porcine mucin admixtures: in vitro and in vivo delivery studies.

Soluble mucus glycoprotein (S-mucin) processed from the small intestines (ileal region) of freshly slaughtered pigs via homogenization, dialysis, centrifugation and lyophilization and their admixtures with type B gelatin were used to prepare cefaclor-loaded microspheres by the emulsification-crosslinking method. The microspheres were evaluated for the in vitro delivery of cefaclor in both simulated intestinal fluid (SIF) without pancreatin (pH 7.4) and simulated gastric fluid (SGF) without pepsin (pH 1.2). Results obtained indicated that the microspheres formulated were highly mucoadhesive and that release of cefaclor in both release media was non-Fickian and was much higher and more rapid in SGF than in SIF and from microspheres based on gelatin alone when compared to those based on gelatin-procine mucin admixtures. The mean area under the plasma level versus time curves (AUC) was shown to be dependent on the formulation with values of 172.3 mug.h/ml for the control, 278.5 mug.h/ml for microspheres based on gelatin only and 353.0 mug.h/ml for microspheres formulated with equal parts of gelatin and mucin indicating that the rectal route may provide a therapeutically viable alternative to the oral route for the delivery of cefaclor. Further indications also emerged of a possibility of site-specific delivery of cefaclor to the small intestine through a careful selection of gelatin type and porcine mucin admixtures prior to formulation of the microspheres. On the whole, the inclusion of S-mucin in the composition of the microspheres had an enhancer effect on the release and rectal bioavailability of cefaclor which may be exploited in the design of a rectal delivery system of the drug.

Preparation and evaluation of mucinated sodium alginate microparticles for oral delivery of insulin.

Effective oral insulin delivery remains a challenge to the pharmaceutical industry. In this study, insulin-loaded microparticles for oral delivery were prepared with mucin and sodium alginate combined at different ratios using a novel method based on polymer coacervation and diffusion filling. Some physical characteristics of the various insulin-loaded microparticles such as particle size, morphology and compressibility indices were determined. The microparticles were filled into hard gelatin capsules and the in vitro insulin release as well as the blood glucose reduction after oral administration to diabetic rabbits were determined. The microparticles formed were generally multi-particulate, discrete and free flowing. Before insulin loading, microparticles were round and smooth, becoming fluffier, less spherical and larger with rough and pitted surface after insulin loading. The insulin content of the microparticles increased with increase in their sodium alginate content. The various insulin-loaded microparticles prepared with the mucinated sodium alginate when encapsulated exhibited lag time before insulin release. The time taken to reach maximum insulin release from the various formulations varied with the mucin-sodium alginate ratio mix. The mean dissolution time of insulin from the microparticles prepared with sodium alginate, mucin, sodium alginate: mucin ratios of 1:1, 3:1 and 1:3 was 11.21+/-0.75, 3.3+/-0.42, 6.69+/-023, 8.52+/-0.95 and 3.48+/-0.65 (min.), respectively. The percentage blood glucose reduction for the subcutaneously administered insulin was significantly (p<0.001) higher than for the formulations. The blood glucose reduction effect produced by the orally administered insulin-loaded microparticles prepared with three parts of sodium alginate and one part of mucin after 5h was, however, equal to that produced by the subcutaneously administered insulin solution, an indication that it is an effective alternative for the delivery of insulin.

Preparation and characterization of mucinated agarose: a mucin-agarose physical crosslink.

Efficient, biocompatible and biodegradable new polymer materials are continually being sought to meet the challenging needs of drug delivery. Mucinated agarose, a physical crosslink of mucin and agarose, which are both biodegradable natural polymers, has been successfully prepared by a temperature controlled coarcervation technique of aqueous dispersions of equal concentrations of both polymers. Some functional and physicochemical characteristics of the new polymer such as swelling, moisture uptake, mucoadhesive as well as the thermal properties were determined and compared to those of agarose and mucin alone. Turbidimetric interaction between the aqueous dispersions of mucin and agarose was used to determine the concentration ratio of optimum interaction between the two polymers. A concentration ratio mix of four parts mucin and six parts agarose was obtained as the concentration ratio of optimum interaction. A 1:1 dispersion mix was, however, used for the crosslinking process. The mucinated agarose showed characteristic swelling, mucoadhesiveness, moisture uptake and DSC thermal properties that were different from those of mucin and agarose alone. The results indicated that there was formation of a crosslink between mucin and agarose.

In vitro evaluation of the antiviral activity of extracts from the lichen Parmelia perlata (L.) Ach. against three RNA viruses.

BACKGROUND: Substances extracted from lichens have previously been reported to possess antimicrobial activities against various groups of bacteria, fungi and viruses. Due to the high abundance of Parmelia perlata in the Eastern parts of Nigeria, we decided to explore whether it possesses antiviral activity against some common animal and human viruses. METHODOLOGY: The dried and powdered lichen was extracted with acetone, water and 4% (v/v) NaOH (to yield a crude polysaccharide fraction) using standard methods. The cytotoxicity of the extracts was investigated on HEP-2, Vero and L20 cell lines. The antiviral properties were determined against yellow fever, poliomyelitis and infectious bursal disease virus of chickens using the end-point cytopathic effect assay. Phytochemical evaluations of the extracts were also carried out. RESULTS: Phytochemical tests showed the presence of flavonoids, saponins, tannins, glycosides, steroidal aglycone, carbohydrates and also the presence, in trace amounts, of some oligodynamic elements. Cytotoxicity tests revealed that while L20 was susceptible to the extracts at a concentration of 50 microg/ml, the extracts were generally toxic to the cell lines at concentrations above 500 microg/ml. The order of sensitivity of the cell lines was L20 > HEP-2 > Vero. The water and acetone extracts showed no activity against the viruses when tested at concentrations below the cytotoxic level while the crude polysaccharide fraction showed activity against yellow fever virus with an IC50 of 15 microg/ml. The time of addition of the test extracts to the infected cells did not have significant effect on cytopathic effect inhibition. CONCLUSIONS: The results showed that the crude polysaccharide fraction from Parmelia perlata possesses specific antiviral activity against yellow fever virus. It is postulated that a major mechanism of inhibition of yellow fever infection by the crude polysaccharide fraction of the lichen could be by attack on the viral envelope.

Evaluation of snail mucin motifs as rectal absorption enhancer for insulin in non-diabetic rat models.

The use of snail mucin motifs as rectal absorption enhancer for insulin has been evaluated. The mucin motifs were extracted from the giant African snail Archachatina marginata by differential precipitation with acetone. The mucin motifs were found to have a molecular weight of 5780 Da and an isoelectric point of 3.4. At the concentrations evaluated, the mucin exhibited rectal absorption enhancing property for the administration of insulin in rats. The % basal blood glucose level of the rats that received the batch of suppositories containing no mucin were consistently above 100% except at the ninetieth minute when it came down slightly to 97.2%. Rats dosed with the batch containing 7%w/w suppositories showed the greatest blood glucose reduction with mean % basal blood glucose concentration of 61.2%. Batches of the suppository containing 5% and 7% mucin showed more marked and consistent lowering in blood glucose concentration than the other batches containing lower amounts of the rectal absorption enhancer. The batch with 7% mucin reduced the basal glucose level to 44% within 2 h of administration of the glycero-gelatin suppository loaded mucin.

Thermodynamic consideration of the charge transfer interaction of the donor: acceptor type between chloranilic acid and haloperidol.

The thermodynamic parameters of the charge transfer complex between chloranilic acid and haloperidol were studied. Haloperidol in pure form and in dosage form was assayed in this study. The method was based on charge transfer complex formation between the drug, which acted as an n-donor, and chloranilic acid, which acted as a pi acceptor in a non aqueous solvent. The complex stoichiometry was found to be 1:2 (haloperidol: chloranilic acid) with the maximum absorption band at a wavelength of 576 nm. The complex obeyed Beer's law. The thermodynamic parameters investigated included stability constant, molar absorptivity, free energy change, enthalpy, and entropy. The method was successfully applied in the analysis of commercially available haloperidol tablets without interference from its excipients, with good precision and reproducibility, compared with the official assay method (non aqueous titration) described for haloperidol in the compendium.

Pharmacodynamic-pharmacokinetic profiles of metformin hydrochloride from a mucoadhesive formulation of a polysaccharide with antidiabetic property in streptozotocin-induced diabetic rat models.

The antidiabetic property of a formulation containing metformin hydrochloride and detarium gum has been evaluated in streptozotocin model of experimental rats. Both the gum and metformin hydrochloride possess antidiabetic properties to varying degrees. The pharmacokinetics of metformin from the mucoadhesive dosage forms indicated that for metformin alone, the area under the curve (AUC) values were 125.6 and 135.6 mgh/ml at 200 and 400 mg/kg BW, respectively. For the mucoadhesive products using the same dose levels, the AUCs were modified to 102.4 and 150.2 in detarium gum and 59.9 and 80.4 in NaCMC. The results indicate that detarium gum is a good excipient for the formulation of metformin mucoadhesive delivery systems when compared with NaCMC. The gum also showed promising antidiabetic effect and should be cautiously used as it may lead to depressed blood-glucose levels beyond the desired levels.

Bioadhesive delivery of metformin using prosopis gum with antidiabetic potential.

The antidiabetic properties of prosopis gum alone and as a bioadhesive base for the delivery of metformin are presented. The bioadhesive value of the gum was commensurate with those of Carbopol 974-P and sodium carboxymethyl cellulose (NaCMC). The release of the drug was higher from prosopis gum based bioadhesive formulations than from NaCMC and Carbopol 974-P products. This was shown by the shorter time required to reach t(50) (the time required for 50% of the drug to be released) or t(20) (time required for 20% of the drug to be released) for the release of metformin. The gum showed moderate antidiabetic properties when used alone. In combination with metformin in a bioadhesive form, the glucose lowering effect was found to be synergistic. The areas under the plasma drug concentration vs. time curves (AUCs) for the bioadhesive combinations were similar to those of the drugs alone in an aqueous system. This shows that the gum did not interfere with absorption of the incorporated drug. However, the areas under the effect vs. time curves (AUECs) were much higher when combined in a bioadhesive form than with the drug alone. The AUCs obtained with NaCMC based bioadhesive formulations were relatively smaller than those of metformin in an aqueous system and the combinations of metformin and prosopis gum.