Interactions between ciprofloxacin and antacids--dissolution and adsorption studies

Ciprofloxacin is a fluorinated quinolone antibacterial agent extensively used against both Gram-positive and Gram-negative microorganisms. In certain polytherapy programs, ciprofloxacin can be administered with some antacids that could modify its dissolution rate and reduce its absorption leading to therapeutic failure. The aim of this study was to evaluate the influence of some antacids on the availability of ciprofloxacin. The release of ciprofloxacin from tablets in the presence of antacids, such as sodium bicarbonate, calcium hydroxide, calcium carbonate, aluminum hydroxide, magnesium hydroxide, magnesium carbonate, magnesium trisilicate and magaldrate was studied on BP 2002 dissolution test apparatus. These studies were carried out in simulated gastric and intestinal juices for 3 hours at 37 degrees C. The results confirmed that the dissolution rate of tablets was markedly retarded in the presence of all the antacids studied. Magaldrate and calcium carbonate in simulated gastric juice exhibited relatively higher adsorption capacities, as did magnesium trisilicate and calcium hydroxide in simulated intestinal juice.     

Phytochemical screening and in vitro bioactivities of the extracts of aerial part of Boerhavia diffusa Linn.

Objective

To investigate the bioactivities of crude n-hexane, ethyl acetate and methanol extracts of aerial part of Boerhavia diffusa Linn. (B. diffusa) and its phytochemical analysis.

Methods

The identification of phytoconstituents and assay of antioxidant, thrombolytic, cytotoxic, antimicrobial activities were conducted using specific standard in vitro procedures.

Results

The results showed that the plant extracts were a rich source of phytoconstituents. Methanol extract showed higher antioxidant, thrombolytic activity and less cytotoxic activity than those of n-hexane and ethyl acetate extracts of B. diffusa. Among the bioactivities, antioxidant activity was the most notable compared to the positive control and thus could be a potential rich source of natural antioxidant. In case of antimicrobial screening, crude extracts of the plant showed remarkable antibacterial activity against tested microorganisms. All the extracts showed significant inhibitory activity against Candida albicuns, at a concentration of 1000 µg/disc.

Conclusions

The present findings suggest that, the plant widely available in Bangladesh, could be a prominent source of medicinally important natural compounds.     

A novel low-cost approach to estimate the incidence of Japanese encephalitis in the catchment area of three hospitals in Bangladesh

Acute meningoencephalitis syndrome surveillance was initiated in three medical college hospitals in Bangladesh in October 2007 to identify Japanese encephalitis (JE) cases. We estimated the population-based incidence of JE in the three hospitals' catchment areas by adjusting the hospital-based crude incidence of JE by the proportion of catchment area meningoencephalitis cases who were admitted to surveillance hospitals. Instead of a traditional house-to-house survey, which is expensive for a disease with low frequency, we attempted a novel approach to identify meningoencephalitis cases in the hospital catchment area through social networks among the community residents. The estimated JE incidence was 2.7/100,000 population in Rajshahi (95% confidence interval [CI] = 1.8-4.9), 1.4 in Khulna (95% CI = 0.9-4.1), and 0.6 in Chittagong (95% CI = 0.4-0.9). Bangladesh should consider a pilot project to introduce JE vaccine in high-incidence areas.     

Alginate microspheres of isoniazid for oral sustained drug delivery

In the present study, spherical microspheres able to prolong the release of INH were produced by a modified emulsification method, using sodium alginate as the hydrophilic carrier. The shape and surface characteristics were determined by scanning electron microscopy using gold sputter technique. Particle sizes of both placebo and drug-loaded formulations were measured by SEM and the particle size distribution was determined by an optical microscope. The physical state of the drug in the formulation was determined by differential scanning calorimetry (DSC). The release profiles of INH from microspheres were examined in simulated gastric fluid (SGF pH 1.2) and simulated intestinal fluid (SIF pH 7.4). Gamma-scintigraphic studies were carried out to determine the location of microspheres on oral administration and the extent of transit through the gastrointestinal tract (GIT). The microspheres had a smoother surface and were found to be discreet and spherical in shape. The particles were heterogeneous with the maximum particles of an average size of 3.719mum. Results indicated that the mean particle size of the microspheres increased with an increase in the concentration of polymer and the cross-linker as well as the cross-linking time. The entrapment efficiency was found to be in the range of 40-91%. Concentration of the cross-linker up to 7.5% caused increase in the entrapment efficiency and the extent of drug release. Optimized isoniazid-alginate microspheres were found to possess good bioadhesion (72.25+/-1.015%). The bioadhesive property of the particles resulted in prolonged retention in the small intestine. Microspheres could be observed in the intestinal lumen at 4h and were detectable in the intestine 24h post-oral administration, although the percent radioactivity had significantly decreased (t(1/2) of (99m)Tc=4-5h). Increased drug loading (91%) was observed for the optimized formulation suggesting the efficiency of the method. Nearly 26% of INH was released in SGF pH 1.2 in 6h and 71.25% in SIF pH 7.4 in 30h. No significant drug-polymer interactions were observed in FT-IR studies. Dissolution and gamma-scintigraphy studies have shown promising results proving the utility of the formulation for enteric drug delivery.     

Bioactive Compounds Isolated from Aloe ferox.: A Plant Traditionally Used for the Treatment of Sexually Transmitted Infections in the Eastern Cape,South Africa

ABSTRACT

Aloe ferox. Mill. is one of the plants used for the treatment of sexually transmitted infections (STIs) in the Eastern Cape province of South Africa. Different extracts of the plant were investigated for their antimicrobial constituents. This led to the isolation of three known compounds, namely, 1,8-dihydroxy-3-hydroxymethyl-9,10-anthracenedione (1, aloe-emodin), 1,8-dihydroxy-3-methyl-9,10-anthracenedione (2, chrysophanol), and 10-C.-β-D-glucopyranosyl-1,8-dihydroxy-3-hydroxymethyl-9-anthracenone (3, aloin A). The structures of the compounds were determined by chemical and spectroscopic studies. The antibacterial activity of the compounds (1–3) was demonstrated using the microplate dilution method.     

Radiolabeling and evaluation of alginate blend-isoniazid microspheres by 99mTc for the treatment of tuberculosis in rabbit model

Isoniazid (INH) is the first line anti-tubercular drug that is widely used in the treatment of tuberculosis. ^99mTc-alginate-INH microsphere scintigraphy has been demonstrated to be a useful noninvasive imaging technique for microsphere deposits located in different organs of the rabbits. The aim of this study was to develop an improved formulation, to validate the formulation for long-time retention, as well as to assess radiotracer stability by novel quality control methods. Our study reports the labeling and evaluation of alginate blends-INH microspheres. The incorporation efficiency of optimized formulation was 89% w/w. The in vitro release study was carried out in simulated intestinal fluid at pH 7.4, and it was found that the formulation delivered the drug for 36 h. The labeling efficiency of ^99mTc-alginate blends-INH microspheres was seen at various pH (i.e. pH ranging from 5 to 7.5) and different concentration of stannous chloride dehydrate (i.e. 25–200 μg) and it was concluded that 96% labeling efficiency was achieved in case of pH 7.5 and 60 μg stannous chloride. The stability study was carried out in saline and serum and it was found that the complex was highly stable in vitro and in vivo. The blood clearance in rabbits showed bi-exponential pattern depicting that 50% of activity washed out at 2 h with t_1/2(Fast) was 2.1 h and t_1/2(Slow) was 12.5 h. Bio-distribution was normal and the experimental mice showed major accumulation of the radiolabeled formulation in liver, intestine, lungs and kidneys, indicating hepatobiliary and renal route of excretion. The distribution of the drugs to the lung was showing its efficiency in the treatment of tuberculosis.     

Simultaneous determination of metformin, captopril, lisinopril, and enalapril by RP-HPLC: its applications in dosage formulations and in human serum

A simple, rapid, isocratic, high-performance liquid chromatography (HPLC) method has been developed for the first time for simultaneous determination of Metformin and ACE inhibitors (lisinopril, captopril, enalapril, and its degradable product) in bulk drugs, pharmaceutical products and in human serum. The separation was performed on a Purospher^® Star RP-18 endcapped (250 mm × 4.6 mm id) column using methanol–water as mobile phase 50:50 (v/v) and 60:40 (v/v) as diluent. The pH of mobile phase was adjusted to 3.2 with ortho-phosphoric acid, flow rate was adjusted to 1 mLmin^?1 at room temperature (25 °C) and analytes peaks were observed using UV detector at 218 nm. The retention times and LOD of lisinopril, enalapril, enalapril diketopiperazine, and captopril were 2.24, 2.63, 3.82, 4.28, and 4.78 min and were 0.028, 0.044, 0.20, 0.016, and 0.145 μgmL^?1 respectively. The method was validated according to ICH guidelines. The linearity of the method was studied over the concentration range of 5–50 μgmL^?1 for metformin and 2.5–250 μgmL^?1 for the ACE inhibitors, where it demonstrated good linearity with r = 0.9998, 0.9979, 0.9997, and 0.9987 (n = 6), respectively. The developed method was successfully applied to quantitate metformin, lisinopril, captopril, and enalapril in pharmaceutical formulations and human serum.     

Drug interactions and synthesis of cefpirome with hypoglycemic agents

The present work is aimed to study the interactions between cefpirome and hypoglycemic agents (gliquidone, metformin, and pioglitazone) by chromatographic and spectroscopic techniques. In the first case, reversed-phase high-performance liquid chromatographic methods have been developed, validated for the simultaneous determination of cefpirome with hypoglycemic agents, and was applied for interaction studies. These interactions were carried out in simulated gastric juice (pH1), buffers of pH 4, 7.4, and 9 at 37 °C for 3 h. In the second case, cefpirome–hypoglycemic agents complexes were synthesized and elucidated on the basis of FT-IR, ¹H-NMR, and ¹³C-NMR studies.