Piperacillin Encapsulation in Nanoliposomes Using Modified Freeze-Drying of a Monophase Solution Method: Preparation, Characterization and In Vitro Antibacterial Activity.

Piperacillin (Pip) is a broad spectrum ß-lactam against most Gram-positive and Gram-negative aerobic and anaerobic bacteria. However, bacterial resistance restricts its benefits for the treatment of infectious diseases. Recently, nanoliposomal systems have been investigated as encouraging strategies to address this issue owing to their immense potential. We aimed to encapsulate Pip in liposomal nanoparticles and study their antibacterial activities in vitro against Pseudomonas aeruginosa (P. aeruginosa). Different liposomes were prepared based on the freeze-drying of a monophase solution method. Then, they were characterized in terms of size, zeta potential, polydispersity-index, and morphology. For further analysis, spectra of ATR-FTIR and XRD were taken for liposomal Pip. Encapsulation efficiency (EE) was determined via agar diffusion assay. Also, minimum inhibitory concentrations (MICs) were investigated by the standard broth macro-dilution method. The liposomes were from 100.9 to 444.13 nm with z-potential of - 30.70 to - 10.57 mV. EE of the selected formulation was 53.1%. TEM results showed that the liposomes were nanosized and almost spherical. ATR-FTIR results confirmed the full encapsulation of Pip in nanoliposomes. The X-ray pattern indicated that the liposomal Pip was amorphous. The MIC (10.6 µg/ml) of the nanoliposomal Pip against P. aeruginosa was one-half of the MIC (21.25 µg/ml) of free Pip for the same organisms. Considering four aspects (nanosized liposomes, no need for sterilization, suitable EE and enhanced antibacterial effects), this preparation method seems promising and may be used to overcome the bacterial resistance relative to Pip.

Targeting of high mobility group A2 by small interfering RNA-loaded nanoliposome-induced apoptosis and migration inhibition in gastrointestinal cancer cells.

BACKGROUND: Considering the complex nature of gastrointestinal cancer, different methods including surgery, radiotherapy, and chemotherapy are considered for the treatment. Novel strategies including silencing of oncogenes using safe delivery systems could be considered as a novel approach in colorectal cancer treatment. The aim of this study was to investigate the silencing effect of high mobility group A2 (HMGA2) small interfering RNA (siRNA)-loaded nanoliposomes on gastrointestinal cancers. METHODS: The siRNA-lipoplexes were prepared using dioleoyl trimethylammonium propane (DOTAP)/cholesterol (Chol)/1, 2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) through the freeze-drying of a monophase solution method. The size, polydispersity index (PDI), and zeta-potential of nanoliposomes were determined using Zetasizer analyzer. The morphology of the nanoliposomes was determined by transmission electron microscopy (TEM). The agarose gel-retardation assay was carried out to confirm the loading of siRNAs into liposome. The silencing of the HMGA2 in cancer cells was evaluated by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The effect of liposomes on cell cytotoxicity was studied by MTT assay. The inhibitory effect of siRNA-loaded liposomes was evaluated by a wound-healing assay. The apoptosis induction was investigated via the annexin V/propidium iodide assay. RESULTS: The size, PDI, and zeta-potential of the prepared liposomes were found to be 350 nm, 0.67, and 86.3 mV, respectively. They were spherical in shape and could efficiently associate with siRNA. The results of gene silencing showed that the optimum condition of HMGA2 silencing was 80 pmol HMGA2 and 24 hours after treatment in each cancer cell lines. MTT assays indicated that silencing of HMGA2 in optimal condition could reduce the viability of the cancer cells more than 60% in the three cell lines. The result of the apoptosis assay showed more than 50% of the cell deaths related to the apoptosis in all three cell lines. The gene expression evaluation confirmed that apoptosis was induced via the intrinsic pathway inducing both caspase-3 and -9 expressions. Also, the reduction in Bcl2 expression confirmed the activation apoptosis pathway in the treated cancer cells. The wound-healing assay showed the suppression of cancer cell migration after treatment with the prepared nanoliposomes. CONCLUSION: The results of this study showed the HMGA2 siRNA-loaded nanoliposomes could be effective in the treatment of gastrointestinal cancers.

Targeted delivery of interleukin-12 plasmid into HepG2 cells through folic acid conjugated graphene oxide nanocarrier.

Successful gene therapy relies on carriers to transfer genetic materials with high efficiency and low toxicity in a targeted manner. To enhance targeted cell binding and uptake, we developed and synthesized a new gene delivery vector based on graphene oxide (GO) modified by branched polyethyleneimine (BPEI) and folic acid (FA). The GO-PEI-FA nanocarriers exhibit lower toxicity compared to unmodified PEI, as well as having the potential to efficiently condense and protect pDNA. Interestingly, increasing the polymer content in the polyplex formulation improved plasmid transfer ability. Substituting graphene oxide for PEI at an N/P ratio of 10 in the HepG2 and THP1 cell lines improved hIL-12 expression by up to approximately eightfold compared to simple PEI, which is twice as high as GO-PEI-FA in Hek293 at the same N/P ratio. Therefore, the GO-PEI-FA described in this study may serve as a targeting nanocarrier for the delivery of the hIL-12 plasmid into cells overexpressing folic acid receptors, such as those found in hepatocellular carcinoma.

Intraperitoneal delivery of nanoparticles for cancer gene therapy.

Nanoparticle-based gene delivery systems may be more efficient for administration of therapeutic genes to solid tumors and cancer metastases, owing to the numerous advantages in terms of enhanced tissue penetrability, improved cellular uptake and targeted gene delivery to the cells of interest compared with other gene delivery systems. Intraperitoneal (IP) delivery of therapeutic agents offers special merits because of the anatomical situation of peritoneum for local cancer therapy. Via the IP administration route, it is possible to target the therapeutic agents exactly to the target cells and protect healthy tissues outside the peritoneal cavity from side effects. IP delivery could be applicable for the treatment of disorders of organs in the peritoneal cavity covered with peritoneum and subperitoneal connective tissue, including cancers such as ovarian and gastric. The goal of this article is to review the current state of IP delivery of nanoparticles for cancer gene therapy.

Preparation and characterization of gelatin nanoparticles containing pDNA encoding IL-12 and their expression in CT-26 carcinoma cells.

AIM: Gelatin as a biodegradable, nontoxic and biocompatible natural protein is a good candidate for gene delivery. In this study, pDNA-loaded gelatin nanoparticles were prepared and characterized for the expression of the cytokine IL-12 and anti-tumor effects. MATERIALS & METHODS: Gelatin-pUMVC3-hIL-12 nanoparticles were prepared by the ethanol precipitation technique and evaluated for physicochemical characteristics, cytotoxiciy and transfection efficiency. RESULTS: The prepared particles were spherical in shape with sizes varying from 344.27 to 826.23 nm, ζ-potentials between -944 and -165 mV, and greater than 97% encapsulation efficiency. The particles were nontoxic to CT-26 carcinoma cells. The nanoparticles prepared using 0.5% gelatin solution (G14) with a mean particle size of 816.87 nm (polydispersity index = 0.56 ± 0.01) demonstrated maximum transfection efficiency with 2.5-times higher expression compared with the naked plasmid. CONCLUSION: Gelatin-DNA nanoparticles using 0.5% gelatin solution had minimal cytotoxicity and can be used as a suitable candidate for further gene delivery studies and applications.

Red onion skin active ingredients, extraction and biological properties for functional food applications.

Onion is an important vegetable in the world and the second most important vegetable crop after tomato.Hence, the onion waste, such as onion skin, is produced in abundance causing environmental problems. Due to its bioactive compounds, especially phenolics and flavonoids, red onion skin can be used through appropriate methods for producing value-added products. These phytochemicals are proven to prevent oxidative stress and broad spectrum of microorganisms beside having diverse beneficial biological properties. Extraction step is the most critical processing in making phytonutrient available. Various approaches including conventional and non-conventional technologies applied for extracting different compounds from red onion wastes was summarized in this study. To evaluate the industrial application potential, the use of natural bioactives derived from red onion skin for elaboration of various food systems has been also investigated.

A novel method for the development of plasmid DNA-loaded nanoliposomes for cancer gene therapy.

We aimed to develop a simple yet novel method to prepare plasmid DNA-loaded nanoliposomes for cancer gene therapy. Murine interleukin-12 (mIL-12) pDNA-loaded nanoliposomes were prepared via novel freeze-drying of a monophase solution method. The physicochemical characteristics, cytotoxicity, and transfection efficiency of the prepared nanoliposomes in murine CT-26 colon carcinoma cells were evaluated. Furthermore, tumor progression and survival rate in CT-26 colon carcinoma-bearing BALB/c mice subsequent to direct intratumoral injections were investigated over a period of 40 days. Using this preparation method, nanoliposomes with particle size of around 300 nm and zeta potential of 96.5 mV were obtained. The transmission electron microscope results showed that the liposomes were nano-sized and almost spherical. The agarose gel retardation assay revealed the pDNA encapsulation in the nanoliposomes. The nanoliposomes with 72.4% encapsulation efficiency and low cell toxicity could significantly improve mIL-12 expression by approximately 25-fold relative to the naked mIL-12 pDNA. There was a significant tumor growth inhibition after repeated injections of mIL-12 pDNA-loaded nanoliposomes. This is the first study on the freeze-drying of a monophase solution method as a simple yet novel technique for the preparation of pDNA-loaded nanoliposomes. Given the ease of preparation method and promising in vitro and in vivo characteristics, this investigation demonstrates advances in pDNA lipid formulation for cancer gene therapy.

Antimicrobial activity of Bacillus sp. isolated strains of wild honey.

BACKGROUND: Multi-drug resistant bacteria hazards to the health of humans could be an agent in the destruction of human generation. Natural products of Bacillus species are the main source to access progressive antibiotics that can be a good candidate for the discovery of novel antibiotics. Wild honey as a valuable food has been used in medicine with antimicrobial effects. OBJECTIVE: Bacillus strains isolated from wild honey were evaluated for the potential antimicrobial activity against human and plant bacterial and fungal pathogens. METHODS: Three bacterial isolates were identified as strain Khuz-1 (98.27% similarity with Bacillus safensis subsp. Safensis strain FO-36bT), strain Khuz-2 (99.18% similarity with Bacillus rugosus strain SPB7T), and strain Khuz-3 (99.78% similarity with Bacillus velezensis strain CR-502 T) by 16S rRNA gene sequences. The strains were characterized by their ability to inhibit the growth of human and phytopathogenic fungi. RESULTS: The results indicated that B. rugosus strain Khuz-2 inhibited the growth of phytopathogenic and human fungal more effective than other ones. It seems that the strain Khuz-2 has a suitable antimicrobial and antifungal potential as a good candidate for further pharmaceutical research. CONCLUSION: Based on the results of GC-MS, Pyrrolo [1,2-a] pyrazine-1,4-dion, hexahydro-3-(2-methylpropyle) (PPDHM) was the major compound for all strains which have a various pharmacological effect. Isolation and identification of beneficial bacteria from natural sources can play an important role in future pharmaceutical and industrial applications.

Preparation of chitosan-plasmid DNA nanoparticles encoding interleukin-12 and their expression in CT-26 colon carcinoma cells.

PURPOSE: Interleukin-12 (Il-12) as a cytokine has been proved to possess antitumor effects via stimulating the immune system. Non-viral gene delivery systems exhibit low toxicity and are easier to prepare compared to their viral counterparts. In this study, we aimed to prepare plasmid DNA loaded chitosan nanoparticles for expression of Il-12 and to evaluate their physicochemical characteristics, cytotoxicity and transfection efficiency in Murine CT-26 colon carcinoma cells. METHODS: Nanoparticles were prepared using a complex coacervation process at different N/P ratios and characterized in terms of size, zeta potential, polydispersity index, morphology, encapsulation efficiency and polyplex formation. The cytotoxicities and transfection efficiencies of the prepared polyplexes were evaluated by MTT assay and ELISA (for hIL-12, p70), respectively. RESULTS: Size and zeta potential varied from 76.73 to 867.03 nm and between 5.68 and 16.77 mV, respectively. Strong attachment of the DNA to chitosan was observed after polyplex preparation. Encapsulation efficiencies were high (72.97-94.87%). The transfection efficiencies of the prepared complexes were obviously higher than those of naked pDNA when N/P ratios were between 16 and 60. Maximum level of phIL-12 expression was obtained at (N/P = 16) with mean particle size of 381.83±82.77 nm (polydispersity index=0.44) indicating the improved transfection of pUMVC3-hIL12 about 2.80 times compared to that of the naked pUMVC3-hIL12. Prepared polyplexes were nontoxic to CT-26 cells. CONCLUSIONS: Chitosan-DNA nanoparticles at N/P = 16 with minimal cytotoxicity, can be used as suitable candidate for Il-12 delivery. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Red cabbage anthocyanins: Stability, extraction, biological activities and applications in food systems.

Red cabbage anthocyanins are of great interest as natural food colorants in the food industry; as they represent the color over a broad range of pH-values compared to anthocyanins from other natural sources. It is important to select an appropriate technique with high recovery of anthocyanins from red cabbage, among which extraction with organic solvents is the most applied extraction method. Currently, novel extraction techniques are employed as an alternative to the solvent extraction method, providing advantages such as higher anthocyanin recovery in a shorter time, lower solvent utilization, and minimum quality degradation. However, the incorporation of extracted anthocyanins into foodstuffs and pharmacological products is limited due to their low bioavailability and relative instability toward environmental adverse conditions, such as pH, temperature, enzymes, light, oxygen and ascorbic acid. In addition to increased structural stability of anthocyanins through glycosylation and acylation, their stability could be improved by copigmentation and encapsulation.

A comprehensive review of in silico approaches for the prediction and modulation of aldehyde oxidase-mediated drug metabolism: The current features, challenges and future perspectives.

The importance of aldehyde oxidase (AOX) in drug metabolism necessitates the development and application of the in silico rational drug design methods as an integral part of drug discovery projects for the early prediction and modulation of AOX-mediated metabolism. The current study represents an up-to-date and thorough review of in silico studies of AOX-mediated metabolism and modulation methods. In addition, the challenges and the knowledge gap that should be covered have been discussed. The importance of aldehyde oxidase (AOX) in drug metabolism is a hot topic in drug discovery. Different strategies are available for the modulation of the AOX-mediated metabolism of drugs. Application of the rational drug design methods as an integral part of drug discovery projects is necessary for the early prediction of AOX-mediated metabolism. The current study represents a comprehensive review of AOX molecular structure, AOX-mediated reactions, AOX substrates, AOX inhibition, approaches to modify AOX-mediated metabolism, prediction of AOX metabolism/substrates/inhibitors, and the AOX related structure-activity relationship (SAR) studies. Furthermore, an up-to-date and thorough review of in silico studies of AOX metabolism has been carried out. In addition, the challenges and the knowledge gap that should be covered in the scientific literature have been discussed in the current review.

Nanoparticle-mediated interleukin-12 cancer gene therapy.

Interleukin-12 (Il-12) is a heterodimeric cytokine which has been proven to possess antitumor effects in various animal models via stimulating the immune system. However, the main problem associated with Il-12 protein delivery is its instability as well as cytotoxicity subsequent to systemic administration in rodents and in clinical trials. However, gene delivery can be used to deliver genes of interest to the tumor site. Hence, a large number of studies have been undertaken to deliver genes of interest to the tumor site through viral or non-viral vectors. Viral DNA delivery systems suffer from safety concern due to the toxicity of the viruses and strong immune response, while non-viral gene delivery systems proffer lower transfection efficiency. In contrast, nanometer-sized complexes of therapeutic DNA may prove to be more efficient for administration of therapeutic genes to solid tumors compared to administration of naked plasmid DNA. Nanoparticle-based gene delivery systems might be more pertinent, due to enhanced tissue penetrability, and improved cellular uptake. Il-12 gene delivery has already been reported with different nanoparticles containing DNA. This article provides a review on the in vivo and in vitro studies using various nanoparticles, for delivery of the Il-12 gene to neoplastic cells. The future of these promising approaches lies in the development of better techniques for preparing Il-12 gene delivery systems with complete efficiency of viral vectors in addition to the highest safety for cancer patients.

Enhancement of percutaneous absorption of finasteride by cosolvents, cosurfactant and surfactants.

The enhancing effects of routinely used co-solvents, propylene glycol and 2-propanol, anionic and cationic surfactants and a co-surfactant with different concentrations were evaluated on the skin permeation of Finasteride. In vitro permeation experiments with rat skin revealed that the solvent mixture is a very important factor in the penetration of Finasteride through the skin. Unexpectedly, cationic and anionic surfactants in various concentrations did not show any enhancement effect on drug transdermal absorption but co-surfactant Transcutol P increased skin penetration of Finastride significantly. Transcutol P with 0.25% and 1% showed the best enhancement in the initial and final sampling time, respectively. Transcutol P in a concentration of 0.25% increased skin absorption of the drug nearly 3.6 times in the first 15 min. The highest enhancement ratio (ER) was gained in the presence of 1% Transcutol P (ER = 5.98). In this study, among the different topical Finastride formulations, Transcutol P 1% in combination with water, propylene glycol and 2-propanol (30, 10, and 60) showed the highest enhancement ratio.

The Effect of Submucosal Injection of Corticosteroids on Pain Perception and Quality of Life after Root Canal Treatment of Teeth with Irreversible Pulpitis: A Randomized Clinical Trial.

INTRODUCTION: The aim of the present investigation was to study the effect of local infiltration of corticosteroids on postoperative pain and quality of life (QOL) in teeth with irreversible pulpitis after 1-visit endodontic treatment. METHODS: In this double-blind randomized clinical trial, 242 healthy patients with irreversible pulpitis undergoing 1-visit endodontic treatment were included. Forty-five patients were lost during the follow-up, and the remaining 197 patients were followed for 7 days (67 patients in the placebo group, 66 in the long-acting betamethasone group, and 64 in the dexamethasone group). The patients marked their level of pain and QOL before treatment and at 6-, 12-, 24-, 48-, and 72-hour and 7-day postoperative intervals using a questionnaire. Freidman and Kruskal-Wallis tests were used for statistical analysis. P ≤ .05 was considered significant. RESULTS: The pain was more severe in the placebo group compared with the other groups at all time intervals. A significant increase was observed in pain severity after 12 hours in all 3 groups. In general, the pain was less severe in the dexamethasone group compared with the betamethasone group at 6-, 12-, and 24-hour intervals. The pain severity was similar in both groups at 48 hours, and it was less severe in the long-acting betamethasone group compared with the dexamethasone group after 72 hours and 7 days. There were no significant differences in the betamethasone and dexamethasone groups in pain intensity between males and females. Moreover, overall pain perception was higher in the mandible than in the maxilla. There was an inverse and significant relationship between pain severity and QOL. CONCLUSIONS: Infiltration of long-acting betamethasone and dexamethasone resulted in decreased postoperative pain experience. Dexamethasone was more effective in alleviating pain within the first 24-hour period after treatment. Infiltration of long-acting betamethasone and dexamethasone exhibited the same efficacy in 48 hours. The efficacy of long-acting betamethasone in pain relief lasted for 7 days. The QOL in the 2 groups receiving corticosteroids was higher than that in the placebo group.

The effects of gene therapy with granulocyte-macrophage colony-stimulating factor in the regression of tumor masses in fibrosarcoma mouse model.

INTRODUCTION: Cytokine gene therapy is one of the cancer treatment strategies. Recently, granulocyte-monocyte colony-stimulating factor (GM-CSF), as an important cytokine in activating dendritic cells and boosting the anti-tumor immune responses, has been utilized as an immunotherapeutic agent in cancer gene therapy. The purpose of the present investigation was to study the GM-CSF gene therapy effects in regression of tumor masses in fibrosarcoma mouse model. MATERIALS AND METHODS: To investigate the therapeutic efficacy of GM-CSF, WEHI-164 tumor cells were transfected with murine GM-CSF plasmid. For cytokine production by transfected cells, enzyme-linked immunosorbent assay test was used. Fibrosarcoma mouse model established with transfected cells which were injected subcutaneously into Balb/c mice. Tumor sizes were measured by caliper. Mice were sacrificed and the tumors were extracted. The expression of GM-CSF was studied by real-time polymerase chain reaction (PCR) and immunoblotting. The expression of Ki-67 (a tumor proliferative marker) in tumor masses was studied by immunohistochemical staining. RESULTS: The group treated with GM-CSF indicated a decrease in tumor mass volume (P = 0.001). The results of western blotting and real-time PCR showed that GM-CSF expression increased in the group treated with GM-CSF (with a relative expression of 1.36). Immunohistochemical staining showed that Ki-67 expression has reduced in the group treated with GM-CSF. CONCLUSION: Monotherapy with GM-CSF has therapeutic effects on the regression of tumor masses in the fibrosarcoma mouse model.

Gene therapy based on interleukin-12 loaded chitosan nanoparticles in a mouse model of fibrosarcoma.

OBJECTIVES: Interleukin-12 (IL-12) as a cytokine has been proved to have a critical role in stimulating the immune system and has been used as immunotherapeutic agents in cancer gene therapy. Chitosan as a polymer, with high ability of binding to nucleic acids is a good candidate for gene delivery since it is biodegradable, biocompatible and non-allergenic polysaccharide. The objective of the present study was to investigate the effects of cells transfected with IL-12 loaded chitosan nanoparticles on the regression of fibrosarcoma tumor cells (WEHI-164) in vivo. MATERIALS AND METHODS: WEHI-164 tumor cells were transfected with IL-12 loaded chitosan nanoparticles and then were injected subcutaneously to inoculate tumor in BALB/c mice. Tumor volumes were determined and subsequently extracted after mice sacrifice. The immunohistochemistry staining was performed for analysis of Ki-67 expression (a tumor proliferation marker) in tumor masses. The expression of IL-12 and IFN-γ were studied using real-time polymerase chain reaction and immunoblotting. RESULTS: The group treated with IL-12 loaded chitosan nanoparticles indicated decreasing of tumor mass[r1] volume (P<0.001). The results of western blotting and real-time PCR showed that the IL-12 expression was increased in the group. Immunohistochemistry staining indicated that the Ki-67expression was reduced in the group treated with IL-12 loaded chitosan nanoparticles. CONCLUSION: IL-12 gene therapy using chitosan nanoparticles has therapeutic effects on the regression of tumor masses in fibrosarcoma mouse model.

Gene therapy with IL-12 induced enhanced anti-tumor activity in fibrosarcoma mouse model.

Context Immunotherapy is among the most promising modalities for treatment of cancer. Recently, interleukin 12 (IL-12) has been used as an immunotherapeutic agent in cancer gene therapy. IL-12 can activate dendritic cells (DCs) and boost anti-tumor immune responses. Objective In the current study, we have investigated if IL-12 gene therapy can lead to the regression of tumor mass in a mouse model of fibrosarcoma. Material and methods To investigate the therapeutic efficacy of IL-12, WEHI-164 tumor cells were transfected with murine-IL12 plasmids using Lipofectamine. Enzyme linked immunosorbent assay (ELISA) was used to confirm IL-12 expression in transfected cells. The fibrosarcoma mouse model was established by subcutaneous injection of transfected cells to Balb/C mice. Mice were sacrificed and the tumors were extracted. Tumor sizes were measured by caliper. The expression of IL-12 and IFN-γ was studied with real-time PCR and western blotting. The expression of Ki-67(a tumor proliferation marker) in tumor mass was studied by immunohistochemistry staining. Results and discussion The group treated with IL-12 showed a significant decrease in tumor mass volume (P: 0.000). The results of real-time PCR and western blotting showed that IL-12 and IFN-γ expression increased in the group treated with IL-12 (relative expression of IL-12: 1.9 and relative expression of IFN-γ: 1.766). Immunohistochemistry staining showed that Ki-67 expression was reduced in the group treated with IL-12. Conclusion IL-12 gene therapy successfully led to regress of tumor mass in the fibrosarcoma mouse model. This may serve as a candidate therapeutic approach for treatment of cancer.

Nanoliposome-based antibacterial drug delivery.

Although most bacterial infectious diseases can be treated successfully with the remarkable array of antibiotics, the microbial pathogens continue to be one of the most critical health challenges worldwide. One of the common efforts in addressing this issue lies in improving the existing antibacterial delivery systems since inefficient delivery can lead to poor therapeutic outcome of the administered drug. Recently, nanoliposomal systems have been widely used as promising strategies to overcome these challenges due to their unique set of properties. This article tries to briefly summarize the current studies that have taken advantage of liposomal nanoparticles as carriers to deliver antibacterial agents. The reviewed investigations demonstrate the immense potential of liposomal nanoparticles as carriers for antibiotic delivery and highlight the latent promise in this class of vehicles for treatment of bacterial infections. The future of these promising approaches lies in the development of more efficient techniques for preparing liposomal nanoparticles with great potential in effective and selective targeting of antibiotics to bacterial cells for eradication as well as the highest safety for human host.

Studies on dissolution enhancement of prednisolone, a poorly water-soluble drug by solid dispersion technique.

INTRODUCTION: Prednisolone is a class II substance according to the Biopharmaceutics Classification System. It is a poorly water soluble agent. The aim of the present study was to improve dissolution rate of a poorly water-soluble drug, prednisolone, by a solid dispersion technique. METHODS: Solid dispersion of prednisolone was prepared with PEG 6000 or different carbohydrates such as lactose and dextrin with various ratios of the drug to carrier i.e., 1:10, 1:20 and 1:40. Solid dispersions were prepared by coevaporation method. The evaluation of the properties of the dispersions was performed using dissolution studies, Fourier-transform infrared spectroscopy and x-ray powder diffractometery. RESULTS: The results indicated that lactose is suitable carriers to enhance the in vitro dissolution rate of prednisolone. The data from the x-ray diffraction showed that the drug was still detectable in its solid state in all solid dispersions except solid dispersions prepared by dextrin as carrier. The results from infrared spectroscopy showed no well-defined drug-carrier interactions for coevaporates. CONCLUSION: Solid dispersion of a poorly water-soluble drug, prednisolone may alleviate the problems of delayed and inconsistent rate of dissolution of the drug.

Comparison of microbiological and high-performance liquid chromatographic methods for determination of clarithromycin levels in plasma.

An agar well diffusion bioassay method for determination of clarithromycin in human plasma, using Micrococcus Luteus ATCC 9341 as the assay organism, was compared with a selective high-performance liquid chromatographic (HPLC) method with UV detection. Spiked plasma was used to prepare standard and control samples for both methods. The results of the bioassay analyses with spiked plasma samples were concordant by HPLC methods (R(2) =0.871, P < 0.001).The Bland-Altman method also showed good agreement between the results of two methods. HPLC demonstrated an improved precision (0.88-19.86% versus 4.51-26.78%) and accuracy (99.27-103.42 % versus 78.52-131.19 %), compared to those of the bioassay method. The range of linearity obtained by both methods (from 62.5 to 3000 ng/ml for HPLC and from 250 to 3000 ng/ml for the bioassay) includes the range of concentrations of clarithromycin which are considered clinically relevant. However, comparison between HPLC and microbiological assays after oral administration of clarithromycin in healthy volunteers indicated significant differences between the two methods in mean plasma concentration-time profiles. The Bland-Altman method revealed no agreement between the two methods, which can be explained by the presence of active metabolites of clarithromycin in plasma.