Research in Pharmaceutical Sciences
Volume:2 Issue: 1, Apr 2007

In recent years, great efforts have been devoted to the design of drug delivery systems. Many polymeric excipients have been studied in order to make drug release fit the desired profiles. The aim of this work was to design a theophylline oral suspension, as sustained release pharmaceutical preparation in order to decrease the plasma level fluctuations and adverse effects of theophylline. Microspheres were prepared by a spray-drying technique using theophylline and two polymers, ethyl cellulose and hydroxy propyl methyl cellulose phthalate (HPMCP) in different solvents and ratios of polymer to drug. The spray-dried microparticles were characterized in terms of shape and drug release. They were formulated in suspensions and evaluated by dissolution and stability studies. The type of polymer and spray dryer feed solution had a major impact on the in vitro performance and release of theophylline from microcapsules and suspensions. Only in the case of the microcapsules derived from HPMCP in acetone (as a solution feed) and ethyl cellulose in methylene chloride (as a suspension feed) in all of polymer to drug ratios, perfect spherical microcapsules with sustained release behavior were observed. Suspensions prepared from HPMCP microcapsules derived in acetone and ethyl cellulose microcapsules in methylene chloride met the requirements of USP for sustained release drug delivery systems. This report documents the suitability of these polymeric suspensions for encapsulated theophylline with a controlled release rate.

Linear furanocoumarins are toxic compounds synthesized by plants. These toxic natural products are usually found in the fruits of Umbelliferae. Heracleum persicum Desf. ex Fischer is an Iranian aromatic medicinal plant from Umbelliferae which their fruits are used as flavoring agent in food products. Because of the wide usage of the fruits of H. persicum it was decided to do a phytochemical study on the fruits of the plant. The fruits of H. persicum were extracted with n-hexane and the extract was put on an open column chromatography. Xanthotoxin (8-methoxypsoralen) was isolated from the fruits of the plant and the structure of the compound was elucidated by UV، IR، NMR and MS analyses. Due to photosensitization caused by this compound، it is recommended to use low amounts of this plant in sensitive patients. However، only further quantitative studies on total furanocoumarins of the fruits can provide definite documents for any phototoxicological hazard.

With the tremendous expansion in the use of herbal medicine worldwide, safety and efficacy as well as quality control of herbal medicine have become important concerns for both health authority and public. In this paper, the analysis of two St. John''s wort (Hypericum perforatum) products and four liquorice (Glycyrrhiza glabra) products by spectrophotometric and HPLC methods, is explained. Moreover chromatographic fingerprinting was done by TLC scanner. Hypericin was chosen as the marker of St. John''s wort products and 18 β-glycyrrhetinic acid was chosen as the marker for post marketing survey of four liquorice commercial formulations. The content of total hypericins that can be expressed as hypericin exist in the sample was 0.008% (mg/100mg) in product A/1 and 0.01% in product B/2. According to the analyses, the content of 18 β-glycyrrhetinic acid in the samples were between 0.002-0.05% (mg/100mg). It is suggested that manufacturers should commit to proper quality control procedures and ensure that label claims for content and dosage are accurate and realistic.

Soil salinity affects ions concentrationss of plant tissues and this may alter the merits quality of medicinal plants. Experiments were conducted during 2003 at the the Isfahan University of Technology Campus, Isfahan, Iran, to assess the effects of five soil salinity levels (3.2, 3.6, 4.5, 5.4 and 7.5 dS m-1) on Na, K, and Ca contents of borage and echium. Each plant species was studied in a separate experiment using a completely randomized design with three replications. The Increase increase in soil salinity increased Na, but decreased K and Ca contents and K/Na ratio of aerial parts of both borage and echium plants. Borage had much higher Na concentration and much lower K/Na ratio than echium. Consequently, it could be implied that the medicinal quality of borage might be more adversely affected by soil salinity than that of echium. Soil salinity should be considered as an important factor for in borage production as a medicinal plant.

Shiga toxin-producing Escherichia coli (STEC) can cause a broad spectrum of human illness. The Progressive progressive increase in antibiotic resistance among enteric pathogens in developing countries is becoming a critical area of concern. The aim of current study was to determine bacterial resistance pattern of a group of diarrheagenic E. coli to some important antibiotics. The research method was descriptive and observational. Isolates of STEC were assessed for susceptibility based on minimum inhibitory concentration method (MIC). MICs were determined by the broth dilution method following the recommendations of the National Committee for Clinical Laboratory, Standards (NCCLS). Of the 29 STEC isolates, 65.5, 72.4, 58.6, 27.6, 13.8, 20.7, 6.9 percentage were rresistant to amoxicillin, trimethoprim-sulfamethoxazole, tetracycline, cefazolin, ceftriaxon, nalidixic acid and ciprofloxacin respectively and all were sensitive to ofloxacin. More than 66% of STEC strains were resistant to the 3 commonly used antibiotics with high MIC90s. According to our study, amoxicillin, tetracycline, and trimethoprim-sulfamethoxazole are not recommended for the treatment of diarrhea in this population. Therefore, regional information regarding antibiotic resistance should be used in clinical management, and treatment guidelines should be updated

Based on the molecular modeling studies on two major families of anxiolytics and sedative hypnotics (benzodiazepines and barbiturates) a series of phthalimide derivatives were prepared from corresponding di-methyl phthalate derivatives in two steps, namely trans-amidification and ring closer of di-methyl phthalate with urea and base catalysed condensation of 4-bromobenzyl chloride and benzoyl chloride with resulting imide. The designed compounds were synthesized with satisfactory yields and chemical structures were confirmed using IR, NMR and Mass spectrophotometery. Among the compounds that were tested for anxiolytic activity using elevated plus-maze technique, N-benzoyl-phthalimide increased the time spent and the number of entries into the open arms at doses of 0.5 mg/kg (P

Lidocaine (LC) is a local anesthetic agent. The aim of this study was to prolong the anesthetic effect of this drug in the oral cavity in the treatment of oral mucositis. Films of LC were prepared with three different molecular weights (MW) of chitosan in three different concentrations (1-3%) and were then cross-linked by solvent casting evaporation method with tripolyphosphate penta sodium salt (TPP) in two concentrations (0.1 and 0.3%). Cross-linking time was 5 min and the solvent was evaporated by oven at 37 ºC. Bioadhesion, tensile strength (TS), the release and flux of drug through the films were studied. Increasing the concentration of chitosan caused decreasing the bioadhesion while increasing its MW did not change the bioadhesion significantly. The bioadhesion of cross-linked films was comparable to similar films. Cross-linking the films with TPP and increasing the chitosan MW significantly increased their TS compared to films obtained from the gels. Drug release profiles showed that increasing the concentration and MW of chitosan caused an increase in both the rate and extent of drug release. Lidocaine flux was increased by MW and concentration of chitosan but increasing TPP concentration significantly decreased it. Films prepared by 3% of high MW of chitosan and cross-linked by 0.1% of TPP (H3T1) showed a higher flux of drug (212.59 ± 26.31 mg/cm2/hr), and relative high bioadhesion and TS. This film is expected to prolong release of LC in buccal area and is suggested for further clinical studies to evaluate its produced onset and duration of anesthesia.

The main objective in classification of the NMR spectra of cancerous and healthy tissue, with high number of features is the prerequisites of the minimum number of samples. Therefore the use of conventional classifier on this type of the data is not recommended. In the current work, different structures of the artificial neural networks (ANN) were tried on classification of different cancerous and healthy tissues. The use of nonlinear classifiers such as ANN could be a proper alternative in NMR spectra classification. The data consists of five type of cancerous and three types of NMR spectra of healthy animal tissues. In the case of multi layer perceptron (MLP), two-layer network with 11 hidden nodes gave the best solution on the current data. In addition MLP + single layer perceptron (SLP) were tried on the current data but it did not make any improvement. Finally the SLP network with log likelihood cost function was tried and in addition to giving the best classification it had a fast convergence time and gave a unique solution on the data independent of the initial seed value off the training. The SLP classifier is better than any other classifiers for the current data.