Anthony attama | University of Nigeria, Nsukka (original) (raw)

Papers by Anthony attama

Biotechnology journal international, Sep 16, 2019

Aims: The study aims to investigate the antimicrobial activities of the leaves, seeds, bark, and ... more Aims: The study aims to investigate the antimicrobial activities of the leaves, seeds, bark, and root of Pterocarpus santalinoides plant. Study Design: Agar well diffusion and Agar well dilution methods were used to test the preliminary antimicrobial and minimum inhibitory/bactericidal/fungicidal concentrations respectively of Pterocarpus santalinoides plants.

Quinine (QHCl) as an antimalarial drug has remained very relevant 400 years after its effectivene... more Quinine (QHCl) as an antimalarial drug has remained very relevant 400 years after its effectiveness was discovered. Unlike other antimalarials, the development of resistance to quinine has been slow. Hence, this drug is till date still used for the treatment of severe and cerebral malaria, for malaria treatment in all trimesters of pregnancy, and in combination with doxycycline against multi-drug resistant parasites. The declined in its administration over the years is mainly associated with poor tolerability due to its gastrointestinal (GIT) side effects such as cinchonism, complex dosing regimen and bitter taste, all of which result in poor compliance. Hence our research was aimed at redesigning quinine using nanotechnology and investigating an alternative route for its administration for the treatment of malaria. A nanosuspension (NS) of QHCl was formulated to suit intranasal administration. QHCl-NS was prepared using lipid matrices made up of solidified reverse micellar solution...

Hosts and viruses, 2022

This research was designed to isolate and test the lytic action of a bacteriophage specific to Es... more This research was designed to isolate and test the lytic action of a bacteriophage specific to Escherichia coli. Both Escherichia coli and bacteriophages were isolated from farmlands and residential wastewaters. The isolated Escherichia coli were confirmed through phenotypic and biochemical tests. Antimicrobial susceptibility test to nine antibiotics was determined. Multi-antibiotic resistance index (MARI) was assessed. Spot assay was done to determine lytic action of the bacteriophage on the lawns of the Escherichia coli. The phenotypic and biochemical tests confirmed Escherichia coli isolates. There was metallic green sheen on EMB agar. The isolates were citrate negative and indole positive. The isolates were found to be resistant to amoxicillin (100 %), meropenem (100 %), and ceftriaxone (100 %). The Multi Antibiotic resistance index (MARI) of the isolates was calculated to be 0.33. The formation of plaques (clear zones of inhibition) on the lawn of the plates of Escherichia coli was confirmed. The isolation of Escherichia coli phages from residential and farm wastewaters is a promising molecular tool for E. coli tracking in the environment.

Frontiers in Pharmacology

Cancer is an important cause of morbidity and mortality worldwide, irrespective of the level of h... more Cancer is an important cause of morbidity and mortality worldwide, irrespective of the level of human development. Globally, it was estimated that there were 19.3 million new cases of cancer and almost 10 million deaths from cancer in 2020. The importance of prevention, early detection as well as effective cancer therapies cannot be over-emphasized. One of the important strategies in cancer therapy is targeted drug delivery to the specific tumor sites. Nanogels are among the several drug delivery systems (DDS) being explored as potential candidates for targeted drug delivery in cancer therapy. Nanogels, which are new generation, versatile DDS with the possession of dual characteristics of hydrogels and nanoparticles have shown great potential as targeted DDS in cancer therapy. Nanogels are hydrogels with a three-dimensional (3D) tunable porous structure and a particle size in the nanometre range, from 20 to 200 nm. They have been visualized as ideal DDS with enormous drug loading ca...

Lipid nanoemulsion-based liquisolid compact tablets for oral delivery of clotrimazole: fabrication strategies, characterizations, antimycotic and toxicological evaluations

Bulletin of Pharmaceutical Sciences. Assiut

BioMed Research International, 2022

Purpose. To assess the improvement in oral bioavailability and efficacy in systemic candidiasis t... more Purpose. To assess the improvement in oral bioavailability and efficacy in systemic candidiasis treatment of miconazole nitrate (MN) formulations in murine models of candidiasis. Methods. Selected formulations containing 5% of Softisan + Phospholipon 90H lipid matrix with 3% of MN ( A 1 ), 5% of stearic acid + Phospholipon 90H lipid matrix with 3% of MN ( B 1 ), and 5% Softisan + stearic acid + Phospholipon 90H with 3% of MN ( C 1 ) from the in vitro investigation were used for the study. Their acute toxicity was assessed using Lorke’s method (with slight modification) while bioavailability was determined using the bioassay method. The optimized batch ( A 1 ) was tested in murine systemic candidiasis induced in cyclophosphamide-immunosuppressed mice. The mice were treated with a single oral dose (100 mg/kg) of the formulations for five days. Serum fungal counts (cfu/mL) were determined on days 1, 3, and 5 of the treatment period. Haematological assessments were done. Results. Th...

Advanced Pharmaceutical Bulletin, 2020

The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it... more The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form.

Purpose: The purpose of the present study is to improve the physicochemical and gastroprotective ... more Purpose: The purpose of the present study is to improve the physicochemical and gastroprotective properties of the BCS class III drug, cimetidine using nanostructured lipid carriers (NLC); thus, improving the overall absorption and bioavailability of cimetidine. Methods: Cimetidine-loaded NLCs were formulated by melt-fusion followed by high pressure homogenization (HPH) using rational blends of the solid lipids, Precirol ATO5 and beeswax, and the liquid lipid, Kolliphor ELP. In vitro physicochemical characterization (particle size, electric charge, polydispersity index, thermal analysis, particle optics, entrapment efficiency) and in vivo gastroprotective evaluations were carried out respectively. Results: Cimetidine-loaded NLCs were stable (-31 to -37 mV), polydispersed (0.1 – 0.4) with particle sizes ranging from 113 – 153 nm. Thermal analysis confirmed that cimetidine was molecularly dispersed in the NLC due to low matrix crystallinity. In vitro release of cimetidine showed susta...

International Journal of Pharmacy and Pharmaceutical Sciences, 2017

Objective: Despite the broad pharmacological activity of gentamicin against a number of bacteria,... more Objective: Despite the broad pharmacological activity of gentamicin against a number of bacteria, it's very inadequate oral bioavailability due to poor intestinal membrane permeability has limited its formulation into oral dosage delivery system. This work was thus aimed at formulation and evaluation of gentamicin-loaded microemulsions based on preparation of lipid matrix for sustained release delivery.Methods: Oral gentamicin suspensions were prepared by emulsification method using Tween 80 as a mobile surfactant in the lipid matrix dispersion. The resultant oral suspensions were evaluated for mean particle size and morphology using a photomicrograph, encapsulation efficiency/entrapment, EE (%), dispersibility, pH and absolute drug content. Release study as a function of inhibition zone diameter (IZD) and in vitro release study was also carried out. The in vitro release study was performed in both simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 7.2) respecti...

Tropical Journal of Pharmaceutical Research, 2016

Purpose: To optimize and characterize amoxicillin encapsulated in mucoadhesive alginate-coated ch... more Purpose: To optimize and characterize amoxicillin encapsulated in mucoadhesive alginate-coated chitosan microparticles for the treatment of gastric and duodenal ulcers caused by Helicobacter pylori. Methods: Eighteen batches of various ratios of chitosan, sodium alginate and calcium chloride were prepared by ionotropic gelation method. The batches were optimized based on their particle size (PS) and drug encapsulation efficiency (PDEE). Optimized batches were further evaluated for in vitro drug release, bacterial susceptibility and mucoadhesion. Results: Microparticle size ranged from 0.70 ± 0.37 to 5.25 ± 0.70 µm. Drug encapsulation efficiency ranged from 95.79 to 97.42 % while maximum drug released after 24 h was 44.79 % in simulated gastric fluid (SGF). Mucoadhesion reached a maximum of 76 % in simulated intestinal fluid (SIF). Drug release followed Higuchi model of release kinetics while the release exponent, n, was > 0.9 in all the formulations. There was a significant difference between the inhibition zone diameter (IZD) of the optimized formulations and that of a commercial brand of amoxicillin when they were tested against Salmonella typhi and Staphylococcus aureus. Conclusion: The mucoadhesive amoxicillin microparticles may improve the treatment of gastric ulcer caused by H. pylori due to enhanced adhesion of the formulation to the pig's ileum and the increased antibacterial property against Salmonella typhi and Staphylococcus aureus.

European Journal of Nanomedicine, 2016

Artemisinins, the mainstay in the treatment of malaria today, are used in combination with other ... more Artemisinins, the mainstay in the treatment of malaria today, are used in combination with other antimalarials to forestall resistance, as artemisinin-combination therapies. In line with the World Health Organization’s recommendation in that respect, solid lipid nanoparticles (SLN) were formulated to encapsulate two antimalarial drugs — artemether and lumefantrine. The nanoparticles were evaluated for size and solid state properties. Caco-2 cells were used to investigate the ability of the SLN to deliver its payload at the absorptive interface of the gastrointestinal tract. Mice heart endothelial cells (MHEC) were also used as marker cells to assess cellular uptake of coumarin 6 from the SLN with imaging by confocal laser scanning microscopy (CSLM). In vivo antimalarial activity was done using a standard suppressive protocol. The results of this study revealed different crystal properties for artemether and lumefantrine, which affected their solubility in the lipid matrix and thus, ...

Drug Delivery, 2013

Effective clinical utilization of non-steroidal anti-inflammatory drugs such as diclofenac sodium... more Effective clinical utilization of non-steroidal anti-inflammatory drugs such as diclofenac sodium (DS) is significantly limited by their ulcerogenic potential and poor bioavailability after oral administration, thus necessitating the need for a better carrier to minimize these obvious limitations. The objective of this study was to evaluate Eudragit Õ RS100/RL100 microspheres formulated by the solvent-evaporation technique for improved delivery of diclofenac. Three batches of (DF1, DF2 and DF3) microspheres were prepared using different ratios of Eudragit RS-100 and RL-100 polymers based on the solvent-evaporation method. The microspheres were characterized based on morphological properties, particle size analysis and encapsulation efficiency (EE%). In vitro release of DS was investigated in both 0.1 N HCl (pH 1.2) and phosphate-buffered saline (pH 7.4), while anti-inflammatory studies were evaluated in the rat model. Maximum EE% of 86.61 AE 0.11, 88.14 AE 0.16 and 85.50 AE 0.21 was obtained for DF1, DF2 and DF3, respectively. Discrete, smooth and brownish microspheres of size range 437 AE 0.01-479 AE 0.21 mm were obtained. Release of DS from the formulation depends on the polymer ratio. All the batches exhibited good anti-inflammatory activities. Microsphere formulations based on Eudragit Õ polymers would likely offer a reliable and alternative means of delivering DS orally.

Drug Delivery, 2009

The aim of this study was to formulate and evaluate in vitro, ceftriaxone sodium lipospheres disp... more The aim of this study was to formulate and evaluate in vitro, ceftriaxone sodium lipospheres dispersions for oral administration. Ceftriaxone sodium lipospheres were prepared by melt-emulsification using 30%w/w Phospholipon  90H in Softisan  154 as the lipid matrix containing increasing quantities of PEG 4000 (10, 20, 30, and 40%w/w). Characterization based on particle size, particle morphology, encapsulation efficiency, loading capacity and pH were carried out on the lipospheres. Microbiological studies of the ceftriaxone sodium-loaded lipospheres were performed using Escherichia coli as the model organism. In vitro permeation of ceftriaxone sodium from the lipospheres through artificial membrane (0.22 µm pore size) was carried out using Franz cell and simulated intestinal fluid (SIF) without pancreatin as acceptor medium. Photomicrographs revealed spherical particles within a micrometer range with minimal growth after 1 month (Maximum size = 64.76 ± 3.81 µm). Microbiological studies indicated that lipospheres formulated with 20%w/w of PEG 4000 containing 2%w/w or 3%w/w of ceftriaxone sodium gave significantly (p < 0.05) higher inhibition zone diameter than those with 30%w/w or 40%w/w of PEG 4000. The result also indicated that lipospheres with 10%w/w PEG 4000 resulted in significantly higher encapsulation efficiency (p < 0.05) while those with 30%w/w gave the least, while the loading capacity values ranged from 3.22 mg of ceftriaxone sodium/100 mg of lipid to 6.36 mg of ceftriaxone sodium/100 mg of lipid. Permeation coefficient values varied and ranged from 8.55 × 10 −7 cm/s to 2.08 × 10 −6 cm/s depending on the concentration of PEG 4000. The result of this study gave insight that the issue of ceftriaxone stability in oral formulation could be adequately addressed by tactical engineering of lipid drug delivery systems such as lipospheres.

Drug Delivery, 2013

The low encapsulation efficiency of conventional solid lipid microparticles (SLMs) especially for... more The low encapsulation efficiency of conventional solid lipid microparticles (SLMs) especially for hydrophilic drugs has remained a challenge to drug formulation experts. This work seeks to address the issue of inefficient delivery of metformin hydrochloride (MTH), a potent hydrophilic oral antihyperglycemic agent, using novel SLMs based on solidified reverse micellar solutions (SRMS) prepared by melt-emulsification using a lipid derived from Capra hircus and Phospholipon Õ 90H. Characterization based on size, morphology, zeta potential, polydispersity index, encapsulation efficiency (EE%), loading capacity (LC) and time-resolved stability were carried out on the SLMs. The in vitro release of MTH from the SLMs was performed in phosphate buffer (pH 7.4) while the in vivo antidiabetic properties were investigated in alloxan-induced diabetic rats. Stable, spherical and smooth SLMs were obtained. Loading of MTH into the SLMs had no effect on the surface charge of the particles. The SLMs with 1.0%w/w PEG 4000 resulted in significantly (p50.05) higher EE% while those with 2.0%w/w gave the least. The LC values ranged from 20.3 to 29.1 and 14.6 to 24.1 for SLMs containing 500 mg and 250 mg of MTH, respectively. The in vitro release studies revealed significant release of MTH from the SLMs whereas the in vivo antidiabetic studies indicated that novel SLMs containing 500 mg of MTH gave significantly (p50.05) higher glucose reduction than glucophage Õ. This research has shown that SLMs based on SRMS offer a new and better approach of delivering MTH, thus encouraging further development of this formulation.

Chemical and Pharmaceutical Bulletin, 2004

The term charge transfer denotes a certain type of complex, which results from interaction of an ... more The term charge transfer denotes a certain type of complex, which results from interaction of an electron acceptor and an electron donor with the formation of weak bonds. 1) Charge transfer complexes result from a donor-acceptor mechanism of the Lewis acid-base reaction between two or more different chemical constituents. The formation of electron donor-acceptor complexes can be rapidly assessed for its validity as a simple qualitative and quantitative analytical method for many drug substances that can act as electron donors. Chloranilic acid and other p-acceptors as well as sigma (s) acceptors have been successfully utilized in the determination of a variety of electron-donating basic compounds. 2-5) Haloperidol is an antipsychotic agent that alters the mental state and behavior in a predictable manner. 6) It is one of the most potent antipsychotic agents available and is less sedative than the phenothiazines. 7) A non aqueous assay procedure was described for haloperidol in the compendia. 8,9) Based on that, an attempt was made to devise an alternative assay procedure for haloperidol both in dosage form and in pure form. The aim of this study therefore was to develop an assay procedure for the analysis of haloperidol both in pure form and in dosage form.

Bio-Research, 2009

This study was aimed at determining the effect of gelatin on the bioadhesive strength and release... more This study was aimed at determining the effect of gelatin on the bioadhesive strength and release properties of gelatin gum. Bioadhesive strength determination was carried out using tensiometric methods. Thiamine tablets was prepared by wet granulation method and used for the study. Tablets properties evaluated include: weight uniformity, friability, disintegration time test and release studies in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF). The study showed that the gelatin alone had the highest bioadhesive strength, while gellan had the least. Admixture of both gelatin and gellan showed values that were intermediate to those obtained for the two polymers differently. The release study showed a better release with batch A (1:1) highest in SIF, followed by F (0:1), and the reverse was the case in SGF.

Acta Pharmaceutica, 2007

Mucuna gum microspheres for oral delivery of glibenclamide:In vitroevaluationAn investigation int... more Mucuna gum microspheres for oral delivery of glibenclamide:In vitroevaluationAn investigation into the suitability of mucuna gum microspheres for oral delivery of glibenclamide is presented. Mucuna gum microspheres were formulated under different conditions of polymer concentration and crosslinking time at constant speed. The formulated microspheres were thereafter loaded with glibenclamide by the remote loading process. The microspheres were evaluated according to particle size, yield, loading efficiency and swelling.In vitrorelease of glibenclamide from the microspheres was studied in simulated intestinal fluid (SIF, pH 7.4). The release data was fitted into two release models to investigate the mechanism of glibenclamide release from the microspheres. All the microspheres showed good swelling characteristics in distilled water. The investigation revealed that the microspheres produced with 5% (m/V) mucuna gum with a crosslinking time of 5 h had the optimum prolonged release patte...

Emerging Trends in Biologics Research and Development

Drug Delivery, 2014

The purpose of this study was to formulate and evaluate novel PEGylated solidified reverse micell... more The purpose of this study was to formulate and evaluate novel PEGylated solidified reverse micellar solutions (SRMS)-based solid lipid microparticles (SLMs) for improved delivery of gentamicin. Lipid matrix (SRMS) [consisting of 15% w/w Phospholipon Õ 90G (P90G) in 35% w/w dika wax (Irvingia gabonensis) was formulated and characterized by differential scanning calorimetry (DSC). SLMs were formulated by melt-emulsification using the SRMS, PEG 4000 and gentamicin (1.0, 2.0, 3.0% w/w), and their physicochemical as well as pharmacokinetic parameters determined. In vitro permeation of gentamicin from the SLMs through artificial membrane (0.22 mm pore size) was carried out using Franz's cell and phosphate-buffered saline (PBS, pH 7.4) as acceptor medium, while bioevaluation was performed using clinical isolates of Pseudomonas aeruginosa and Staphylococcus aureus. Stable and irregularly-shaped gentamicinloaded SLMs of size range 34.49 ± 2.56 to 53.52 ± 3.09 mm were obtained. The SLMs showed sustained drug permeation and exhibited time-dependent and capacity-limited bioactivity. Overall, SLMs containing 2% w/w SRMS, 3% w/w gentamicin and PEG 4000 entrapped the highest amount of drug, gave highest IZD against the test organisms and highest permeation flux (5.239 mg/cm 2 .min) and permeation coefficient (1.781 Â 10 À6 cm/min) within 420 min, while pure gentamicin gave the least. Preliminary in vivo pharmacokinetic studies also showed an AUC-24 of 1507 mg/h/ml for the optimized formulation, while that of oral drug solution was 678 mg/h/ml. This showed a 2.2-fold increase in the systemic bioavailability of gentamicin from the optimized formulation. PEGylated SRMS-based SLMs prepared with heterolipid from Irvingia gabonensis would likely offer a reliable delivery system for gentamicin.

The term “nanoscale ” refers to particle size range from ~ 1 to 100 nm [1], but for the purpose o... more The term “nanoscale ” refers to particle size range from ~ 1 to 100 nm [1], but for the purpose of drug delivery, nanoparticles in the range of 50 – 500 nm are acceptable depending on the route of administration. The method by which a drug is delivered can have a significant effect on its efficacy. Some drugs have an optimum concentration range within which maximum

Biotechnology journal international, Sep 16, 2019

Aims: The study aims to investigate the antimicrobial activities of the leaves, seeds, bark, and ... more Aims: The study aims to investigate the antimicrobial activities of the leaves, seeds, bark, and root of Pterocarpus santalinoides plant. Study Design: Agar well diffusion and Agar well dilution methods were used to test the preliminary antimicrobial and minimum inhibitory/bactericidal/fungicidal concentrations respectively of Pterocarpus santalinoides plants.

Quinine (QHCl) as an antimalarial drug has remained very relevant 400 years after its effectivene... more Quinine (QHCl) as an antimalarial drug has remained very relevant 400 years after its effectiveness was discovered. Unlike other antimalarials, the development of resistance to quinine has been slow. Hence, this drug is till date still used for the treatment of severe and cerebral malaria, for malaria treatment in all trimesters of pregnancy, and in combination with doxycycline against multi-drug resistant parasites. The declined in its administration over the years is mainly associated with poor tolerability due to its gastrointestinal (GIT) side effects such as cinchonism, complex dosing regimen and bitter taste, all of which result in poor compliance. Hence our research was aimed at redesigning quinine using nanotechnology and investigating an alternative route for its administration for the treatment of malaria. A nanosuspension (NS) of QHCl was formulated to suit intranasal administration. QHCl-NS was prepared using lipid matrices made up of solidified reverse micellar solution...

Hosts and viruses, 2022

This research was designed to isolate and test the lytic action of a bacteriophage specific to Es... more This research was designed to isolate and test the lytic action of a bacteriophage specific to Escherichia coli. Both Escherichia coli and bacteriophages were isolated from farmlands and residential wastewaters. The isolated Escherichia coli were confirmed through phenotypic and biochemical tests. Antimicrobial susceptibility test to nine antibiotics was determined. Multi-antibiotic resistance index (MARI) was assessed. Spot assay was done to determine lytic action of the bacteriophage on the lawns of the Escherichia coli. The phenotypic and biochemical tests confirmed Escherichia coli isolates. There was metallic green sheen on EMB agar. The isolates were citrate negative and indole positive. The isolates were found to be resistant to amoxicillin (100 %), meropenem (100 %), and ceftriaxone (100 %). The Multi Antibiotic resistance index (MARI) of the isolates was calculated to be 0.33. The formation of plaques (clear zones of inhibition) on the lawn of the plates of Escherichia coli was confirmed. The isolation of Escherichia coli phages from residential and farm wastewaters is a promising molecular tool for E. coli tracking in the environment.

Frontiers in Pharmacology

Cancer is an important cause of morbidity and mortality worldwide, irrespective of the level of h... more Cancer is an important cause of morbidity and mortality worldwide, irrespective of the level of human development. Globally, it was estimated that there were 19.3 million new cases of cancer and almost 10 million deaths from cancer in 2020. The importance of prevention, early detection as well as effective cancer therapies cannot be over-emphasized. One of the important strategies in cancer therapy is targeted drug delivery to the specific tumor sites. Nanogels are among the several drug delivery systems (DDS) being explored as potential candidates for targeted drug delivery in cancer therapy. Nanogels, which are new generation, versatile DDS with the possession of dual characteristics of hydrogels and nanoparticles have shown great potential as targeted DDS in cancer therapy. Nanogels are hydrogels with a three-dimensional (3D) tunable porous structure and a particle size in the nanometre range, from 20 to 200 nm. They have been visualized as ideal DDS with enormous drug loading ca...

Lipid nanoemulsion-based liquisolid compact tablets for oral delivery of clotrimazole: fabrication strategies, characterizations, antimycotic and toxicological evaluations

Bulletin of Pharmaceutical Sciences. Assiut

BioMed Research International, 2022

Purpose. To assess the improvement in oral bioavailability and efficacy in systemic candidiasis t... more Purpose. To assess the improvement in oral bioavailability and efficacy in systemic candidiasis treatment of miconazole nitrate (MN) formulations in murine models of candidiasis. Methods. Selected formulations containing 5% of Softisan + Phospholipon 90H lipid matrix with 3% of MN ( A 1 ), 5% of stearic acid + Phospholipon 90H lipid matrix with 3% of MN ( B 1 ), and 5% Softisan + stearic acid + Phospholipon 90H with 3% of MN ( C 1 ) from the in vitro investigation were used for the study. Their acute toxicity was assessed using Lorke’s method (with slight modification) while bioavailability was determined using the bioassay method. The optimized batch ( A 1 ) was tested in murine systemic candidiasis induced in cyclophosphamide-immunosuppressed mice. The mice were treated with a single oral dose (100 mg/kg) of the formulations for five days. Serum fungal counts (cfu/mL) were determined on days 1, 3, and 5 of the treatment period. Haematological assessments were done. Results. Th...

Advanced Pharmaceutical Bulletin, 2020

The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it... more The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form.

Purpose: The purpose of the present study is to improve the physicochemical and gastroprotective ... more Purpose: The purpose of the present study is to improve the physicochemical and gastroprotective properties of the BCS class III drug, cimetidine using nanostructured lipid carriers (NLC); thus, improving the overall absorption and bioavailability of cimetidine. Methods: Cimetidine-loaded NLCs were formulated by melt-fusion followed by high pressure homogenization (HPH) using rational blends of the solid lipids, Precirol ATO5 and beeswax, and the liquid lipid, Kolliphor ELP. In vitro physicochemical characterization (particle size, electric charge, polydispersity index, thermal analysis, particle optics, entrapment efficiency) and in vivo gastroprotective evaluations were carried out respectively. Results: Cimetidine-loaded NLCs were stable (-31 to -37 mV), polydispersed (0.1 – 0.4) with particle sizes ranging from 113 – 153 nm. Thermal analysis confirmed that cimetidine was molecularly dispersed in the NLC due to low matrix crystallinity. In vitro release of cimetidine showed susta...

International Journal of Pharmacy and Pharmaceutical Sciences, 2017

Objective: Despite the broad pharmacological activity of gentamicin against a number of bacteria,... more Objective: Despite the broad pharmacological activity of gentamicin against a number of bacteria, it's very inadequate oral bioavailability due to poor intestinal membrane permeability has limited its formulation into oral dosage delivery system. This work was thus aimed at formulation and evaluation of gentamicin-loaded microemulsions based on preparation of lipid matrix for sustained release delivery.Methods: Oral gentamicin suspensions were prepared by emulsification method using Tween 80 as a mobile surfactant in the lipid matrix dispersion. The resultant oral suspensions were evaluated for mean particle size and morphology using a photomicrograph, encapsulation efficiency/entrapment, EE (%), dispersibility, pH and absolute drug content. Release study as a function of inhibition zone diameter (IZD) and in vitro release study was also carried out. The in vitro release study was performed in both simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 7.2) respecti...

Tropical Journal of Pharmaceutical Research, 2016

Purpose: To optimize and characterize amoxicillin encapsulated in mucoadhesive alginate-coated ch... more Purpose: To optimize and characterize amoxicillin encapsulated in mucoadhesive alginate-coated chitosan microparticles for the treatment of gastric and duodenal ulcers caused by Helicobacter pylori. Methods: Eighteen batches of various ratios of chitosan, sodium alginate and calcium chloride were prepared by ionotropic gelation method. The batches were optimized based on their particle size (PS) and drug encapsulation efficiency (PDEE). Optimized batches were further evaluated for in vitro drug release, bacterial susceptibility and mucoadhesion. Results: Microparticle size ranged from 0.70 ± 0.37 to 5.25 ± 0.70 µm. Drug encapsulation efficiency ranged from 95.79 to 97.42 % while maximum drug released after 24 h was 44.79 % in simulated gastric fluid (SGF). Mucoadhesion reached a maximum of 76 % in simulated intestinal fluid (SIF). Drug release followed Higuchi model of release kinetics while the release exponent, n, was > 0.9 in all the formulations. There was a significant difference between the inhibition zone diameter (IZD) of the optimized formulations and that of a commercial brand of amoxicillin when they were tested against Salmonella typhi and Staphylococcus aureus. Conclusion: The mucoadhesive amoxicillin microparticles may improve the treatment of gastric ulcer caused by H. pylori due to enhanced adhesion of the formulation to the pig's ileum and the increased antibacterial property against Salmonella typhi and Staphylococcus aureus.

European Journal of Nanomedicine, 2016

Artemisinins, the mainstay in the treatment of malaria today, are used in combination with other ... more Artemisinins, the mainstay in the treatment of malaria today, are used in combination with other antimalarials to forestall resistance, as artemisinin-combination therapies. In line with the World Health Organization’s recommendation in that respect, solid lipid nanoparticles (SLN) were formulated to encapsulate two antimalarial drugs — artemether and lumefantrine. The nanoparticles were evaluated for size and solid state properties. Caco-2 cells were used to investigate the ability of the SLN to deliver its payload at the absorptive interface of the gastrointestinal tract. Mice heart endothelial cells (MHEC) were also used as marker cells to assess cellular uptake of coumarin 6 from the SLN with imaging by confocal laser scanning microscopy (CSLM). In vivo antimalarial activity was done using a standard suppressive protocol. The results of this study revealed different crystal properties for artemether and lumefantrine, which affected their solubility in the lipid matrix and thus, ...

Drug Delivery, 2013

Effective clinical utilization of non-steroidal anti-inflammatory drugs such as diclofenac sodium... more Effective clinical utilization of non-steroidal anti-inflammatory drugs such as diclofenac sodium (DS) is significantly limited by their ulcerogenic potential and poor bioavailability after oral administration, thus necessitating the need for a better carrier to minimize these obvious limitations. The objective of this study was to evaluate Eudragit Õ RS100/RL100 microspheres formulated by the solvent-evaporation technique for improved delivery of diclofenac. Three batches of (DF1, DF2 and DF3) microspheres were prepared using different ratios of Eudragit RS-100 and RL-100 polymers based on the solvent-evaporation method. The microspheres were characterized based on morphological properties, particle size analysis and encapsulation efficiency (EE%). In vitro release of DS was investigated in both 0.1 N HCl (pH 1.2) and phosphate-buffered saline (pH 7.4), while anti-inflammatory studies were evaluated in the rat model. Maximum EE% of 86.61 AE 0.11, 88.14 AE 0.16 and 85.50 AE 0.21 was obtained for DF1, DF2 and DF3, respectively. Discrete, smooth and brownish microspheres of size range 437 AE 0.01-479 AE 0.21 mm were obtained. Release of DS from the formulation depends on the polymer ratio. All the batches exhibited good anti-inflammatory activities. Microsphere formulations based on Eudragit Õ polymers would likely offer a reliable and alternative means of delivering DS orally.

Drug Delivery, 2009

The aim of this study was to formulate and evaluate in vitro, ceftriaxone sodium lipospheres disp... more The aim of this study was to formulate and evaluate in vitro, ceftriaxone sodium lipospheres dispersions for oral administration. Ceftriaxone sodium lipospheres were prepared by melt-emulsification using 30%w/w Phospholipon  90H in Softisan  154 as the lipid matrix containing increasing quantities of PEG 4000 (10, 20, 30, and 40%w/w). Characterization based on particle size, particle morphology, encapsulation efficiency, loading capacity and pH were carried out on the lipospheres. Microbiological studies of the ceftriaxone sodium-loaded lipospheres were performed using Escherichia coli as the model organism. In vitro permeation of ceftriaxone sodium from the lipospheres through artificial membrane (0.22 µm pore size) was carried out using Franz cell and simulated intestinal fluid (SIF) without pancreatin as acceptor medium. Photomicrographs revealed spherical particles within a micrometer range with minimal growth after 1 month (Maximum size = 64.76 ± 3.81 µm). Microbiological studies indicated that lipospheres formulated with 20%w/w of PEG 4000 containing 2%w/w or 3%w/w of ceftriaxone sodium gave significantly (p < 0.05) higher inhibition zone diameter than those with 30%w/w or 40%w/w of PEG 4000. The result also indicated that lipospheres with 10%w/w PEG 4000 resulted in significantly higher encapsulation efficiency (p < 0.05) while those with 30%w/w gave the least, while the loading capacity values ranged from 3.22 mg of ceftriaxone sodium/100 mg of lipid to 6.36 mg of ceftriaxone sodium/100 mg of lipid. Permeation coefficient values varied and ranged from 8.55 × 10 −7 cm/s to 2.08 × 10 −6 cm/s depending on the concentration of PEG 4000. The result of this study gave insight that the issue of ceftriaxone stability in oral formulation could be adequately addressed by tactical engineering of lipid drug delivery systems such as lipospheres.

Drug Delivery, 2013

The low encapsulation efficiency of conventional solid lipid microparticles (SLMs) especially for... more The low encapsulation efficiency of conventional solid lipid microparticles (SLMs) especially for hydrophilic drugs has remained a challenge to drug formulation experts. This work seeks to address the issue of inefficient delivery of metformin hydrochloride (MTH), a potent hydrophilic oral antihyperglycemic agent, using novel SLMs based on solidified reverse micellar solutions (SRMS) prepared by melt-emulsification using a lipid derived from Capra hircus and Phospholipon Õ 90H. Characterization based on size, morphology, zeta potential, polydispersity index, encapsulation efficiency (EE%), loading capacity (LC) and time-resolved stability were carried out on the SLMs. The in vitro release of MTH from the SLMs was performed in phosphate buffer (pH 7.4) while the in vivo antidiabetic properties were investigated in alloxan-induced diabetic rats. Stable, spherical and smooth SLMs were obtained. Loading of MTH into the SLMs had no effect on the surface charge of the particles. The SLMs with 1.0%w/w PEG 4000 resulted in significantly (p50.05) higher EE% while those with 2.0%w/w gave the least. The LC values ranged from 20.3 to 29.1 and 14.6 to 24.1 for SLMs containing 500 mg and 250 mg of MTH, respectively. The in vitro release studies revealed significant release of MTH from the SLMs whereas the in vivo antidiabetic studies indicated that novel SLMs containing 500 mg of MTH gave significantly (p50.05) higher glucose reduction than glucophage Õ. This research has shown that SLMs based on SRMS offer a new and better approach of delivering MTH, thus encouraging further development of this formulation.

Chemical and Pharmaceutical Bulletin, 2004

The term charge transfer denotes a certain type of complex, which results from interaction of an ... more The term charge transfer denotes a certain type of complex, which results from interaction of an electron acceptor and an electron donor with the formation of weak bonds. 1) Charge transfer complexes result from a donor-acceptor mechanism of the Lewis acid-base reaction between two or more different chemical constituents. The formation of electron donor-acceptor complexes can be rapidly assessed for its validity as a simple qualitative and quantitative analytical method for many drug substances that can act as electron donors. Chloranilic acid and other p-acceptors as well as sigma (s) acceptors have been successfully utilized in the determination of a variety of electron-donating basic compounds. 2-5) Haloperidol is an antipsychotic agent that alters the mental state and behavior in a predictable manner. 6) It is one of the most potent antipsychotic agents available and is less sedative than the phenothiazines. 7) A non aqueous assay procedure was described for haloperidol in the compendia. 8,9) Based on that, an attempt was made to devise an alternative assay procedure for haloperidol both in dosage form and in pure form. The aim of this study therefore was to develop an assay procedure for the analysis of haloperidol both in pure form and in dosage form.

Bio-Research, 2009

This study was aimed at determining the effect of gelatin on the bioadhesive strength and release... more This study was aimed at determining the effect of gelatin on the bioadhesive strength and release properties of gelatin gum. Bioadhesive strength determination was carried out using tensiometric methods. Thiamine tablets was prepared by wet granulation method and used for the study. Tablets properties evaluated include: weight uniformity, friability, disintegration time test and release studies in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF). The study showed that the gelatin alone had the highest bioadhesive strength, while gellan had the least. Admixture of both gelatin and gellan showed values that were intermediate to those obtained for the two polymers differently. The release study showed a better release with batch A (1:1) highest in SIF, followed by F (0:1), and the reverse was the case in SGF.

Acta Pharmaceutica, 2007

Mucuna gum microspheres for oral delivery of glibenclamide:In vitroevaluationAn investigation int... more Mucuna gum microspheres for oral delivery of glibenclamide:In vitroevaluationAn investigation into the suitability of mucuna gum microspheres for oral delivery of glibenclamide is presented. Mucuna gum microspheres were formulated under different conditions of polymer concentration and crosslinking time at constant speed. The formulated microspheres were thereafter loaded with glibenclamide by the remote loading process. The microspheres were evaluated according to particle size, yield, loading efficiency and swelling.In vitrorelease of glibenclamide from the microspheres was studied in simulated intestinal fluid (SIF, pH 7.4). The release data was fitted into two release models to investigate the mechanism of glibenclamide release from the microspheres. All the microspheres showed good swelling characteristics in distilled water. The investigation revealed that the microspheres produced with 5% (m/V) mucuna gum with a crosslinking time of 5 h had the optimum prolonged release patte...

Emerging Trends in Biologics Research and Development

Drug Delivery, 2014

The purpose of this study was to formulate and evaluate novel PEGylated solidified reverse micell... more The purpose of this study was to formulate and evaluate novel PEGylated solidified reverse micellar solutions (SRMS)-based solid lipid microparticles (SLMs) for improved delivery of gentamicin. Lipid matrix (SRMS) [consisting of 15% w/w Phospholipon Õ 90G (P90G) in 35% w/w dika wax (Irvingia gabonensis) was formulated and characterized by differential scanning calorimetry (DSC). SLMs were formulated by melt-emulsification using the SRMS, PEG 4000 and gentamicin (1.0, 2.0, 3.0% w/w), and their physicochemical as well as pharmacokinetic parameters determined. In vitro permeation of gentamicin from the SLMs through artificial membrane (0.22 mm pore size) was carried out using Franz's cell and phosphate-buffered saline (PBS, pH 7.4) as acceptor medium, while bioevaluation was performed using clinical isolates of Pseudomonas aeruginosa and Staphylococcus aureus. Stable and irregularly-shaped gentamicinloaded SLMs of size range 34.49 ± 2.56 to 53.52 ± 3.09 mm were obtained. The SLMs showed sustained drug permeation and exhibited time-dependent and capacity-limited bioactivity. Overall, SLMs containing 2% w/w SRMS, 3% w/w gentamicin and PEG 4000 entrapped the highest amount of drug, gave highest IZD against the test organisms and highest permeation flux (5.239 mg/cm 2 .min) and permeation coefficient (1.781 Â 10 À6 cm/min) within 420 min, while pure gentamicin gave the least. Preliminary in vivo pharmacokinetic studies also showed an AUC-24 of 1507 mg/h/ml for the optimized formulation, while that of oral drug solution was 678 mg/h/ml. This showed a 2.2-fold increase in the systemic bioavailability of gentamicin from the optimized formulation. PEGylated SRMS-based SLMs prepared with heterolipid from Irvingia gabonensis would likely offer a reliable delivery system for gentamicin.

The term “nanoscale ” refers to particle size range from ~ 1 to 100 nm [1], but for the purpose o... more The term “nanoscale ” refers to particle size range from ~ 1 to 100 nm [1], but for the purpose of drug delivery, nanoparticles in the range of 50 – 500 nm are acceptable depending on the route of administration. The method by which a drug is delivered can have a significant effect on its efficacy. Some drugs have an optimum concentration range within which maximum