Iranian Journal of Pharmaceutical Research
Volume:9 Issue: 3, summer 2010

The present study concerned with the development and characterization of metronidazole microcapsules prepared by thermal change method using different ratios (1:1, 1:2 and 1:4) of ethyl cellulose in order to select the best microcapsule formulation with a good encapsulation efficiency and drug release profile. The obtained microcapsules were discrete, spherical with free flowing properties and evaluated for particle size, shape, flow properties, wall thickness, drug encapsulation efficiency and in vitro release performance. The drug carrier interactions were investigated in solid state by FT-IR spectroscopy and scanning electron microscopy. The microcapsules with a narrow size range of 23-68 µm showed higher encapsulation efficiency. The selected microcapsule formulation, MC3 (Drug polymer ratio 1:4) was employed for gel formulation with a variety of carbopol polymers (carbopol-934, 940, 974 and 980) by mechanical stirring method in order to develop a sustained release microencapsulated metronidazole microcapsules-containing bioadhesive gel. The prepared bioadhesive gels were evaluated for pH, spreadability, extrudability, viscosity, vaginal irritation, in vitro drug release, bioadhesion, accelerated stability and in vitro drug release kinetic. In vitro experiments indicated a sustained release over 24 h and an acceptable bioadhesion quality for formulation F3. Hence, it can be concluded that the formulation F3 has potential to deliver metronidazole in a controlled and constant manner for prolong period over other formulations and can be adopted for a successful delivery of metronidazole for vaginal use.

The purpose of this research was to formulate and systemically evaluate in-vitro and in-vivo performances of mucoadhesive propranolol hydrochloride microspheres for its potential use in the treatment of hypertension, myocardial infraction and cardiac arrhythmias. Propranolol hydrochloride mucoadhesive microspheres, containing carbopol-934P as mucoadhesive polymer and ethyl cellulose as carrier polymer, were prepared by an emulsion-solvent evaporation technique. Results of preliminary trials indicated that the quantity of emulsifying agent, time for stirring, drug-to-polymers ratio, and speed of rotation affected various characteristics of microspheres. Microspheres were discrete, spherical, free-flowing and showed a good percentage of drug entrapment efficiency. An in-vitro mucoadhesive test showed that propranolol hydrochloride mucoadhesive microspheres adhered more strongly to the gastric mucous layer and could be retained in the gastrointestinal tract for an extended period of time. A 32 full factorial design was employed to study the effect of independent variables, drug-to-polymer-to-polymer ratio (propranolol hydrochloride-ethyl cellulose-carbopol-934P) (X1), and stirring speed (X2) on dependent variables, i.e. percentage of mucoadhesion, drug entrapment efficiency, particle size and t80. The best batch exhibited a high drug entrapment efficiency of 54 %; 82% mucoadhesion after 1 h and particle size of 110 µm. A sustained pattern of drug release was obtained for more than 12 h. The drug-to-polymer-to-polymer ratio had a more significant effect on the dependent variables. The morphological characteristics of the mucoadhesive microspheres were studied under a scanning electron microscope. In-vivo evaluation studies on propranolol hydrochloride mucoadhesive microspheres and propranolol hydrochloride powder were performed on normal healthy rabbits. The results showed a sustained anti-hypertensive effect over a longer period of time in case of mucoadhesive microspheres, compared to the powder. In conclusion, the prolonged gastrointestinal residence time and slow release of propranolol hydrochloride resulting from the mucoadhesive microspheres, could contribute to the provision of a sustained anti-hypertensive effect.

Aceclofenac is a non-steroidal anti-inflammatory drug (NSAID) that exhibits analgesic, antipyretic and anti-inflammatory activities. It is practically insoluble in water. The effect of hydrotropes such as urea and sodium citrate and blends (urea + sodium citrate) on the solubility of aceclofenac was investigated. The enhancement in the solubility of aceclofenac was more than 5 and 25 folds in 30% sodium citrate solution and 30% urea solution, respectively, as compared to its solubility in distilled water. The enhancement in the solubility of aceclofenac in a mixed hydrotropic solution containing ≥ 20% urea and 10% sodium citrate solution was more than 250 folds (compared to its solubility in distilled water). This proved a synergistic enhancement in solubility of a poorly water- soluble drug due to mixed hydrotropy. Synergistic combination of hydrotropic agents can minimize the amount of hydrotropic agents employed, minimizing the chances of their toxicities. Aqueous injection of aceclofenac, using the mixed hydrotropic solubilization technique, was developed and by using the lyophilization method, the problem of inadequate stability of aceclofenac in aqueous solution was overcome. The developed formulation was studied for physical and chemical stability.

Clomipramine is a tricyclic antidepressant. Different methods for determination of clomipramine hydrochloride in plasma have been described. Most of these procedures favor the use of acidic back-extraction in extraction procedure and HPLC as the analytical technique. In this study, the clomipramine extraction procedure was modified and a direct injection to the column was performed to shorten the time of sample preparation considerably. Furthermore, the method was applied in bioequivalence study of new formulations of clomipramine in comparison with reference tablets. The drug and internal standard were extracted from plasma with heptan: isoamyl alcohol (95:5) and re-extracted with 200 µL of orthophosphoric acid (0.3% v/v). The organic layer was discharged and analysis was performed on C8 reverse phase ODS2 HPLC column with a mobile phase, acetonitrile: water (75:25) and UV detection set at 215 nm. Additionally, a single dose study was carried out with a two-sequence, crossover block-randomized design for bioequivalence study. Clomipramine tablets (3 × 25 mg) of either formulations (reference or test products) were administered separately in two occasions to 12 fasting healthy male volunteers. Blood samples were taken prior to and at 9 points within 48 h after dose administration.The retention time of internal standard (cisapride), clomipramine, and desmethyl clomipramine were 5.6 ± 0.2, 10.3 ± 0.3, and 9.5 ± 0.3 min, respectively. The standard curve covering the concentration ranges of 2.5-120 ng/mL was linear (r2 = 0.9950 and 0.9979) for clomipramine and desmethyl clomipramine. The co-efficient of variation for intra-day and inter-day accuracy and precision was less than 18.3%. The pharmacokinetic parameters Cmax and Tmax were obtained directly from plasma clomipramine concentrations. Kel was estimated by log-linear regression and AUC was calculated by the linear trapezoidal rule. The pharmacokinetic parameters AUC and Cmax were tested for equivalence after log-transformation of data. The 90% standard confidence intervals of the mean values for the test/reference ratios, AUC, and Cmax were within the acceptable bioequivalence limits of 0.80-1.20.These results indicated that the analytical method was linear and accurate. Test and reference formulations were found to be bioequivalent and therefore interchangeable.

Human serum albumin (HSA) is the most abundant plasma protein in the human body. HSA plays an important role in drug transport and metabolism. This protein has a high affinity to a very wide range of materials, including metals such as Cu2+ and Zn2+, fatty acids, amino acids and metabolites such as bilirubin and many drug compounds. In this study, we investigated the effects of co-amoxiclav, as a drug which could be carried by this protein, on HSA structure and binding properties via spectroscopy and electrochemistry techniques. Based on this study, it was found that a therapeutic dose of co-amoxiclav as well as doses 4 to 8 folds higher than the therapeutic dose has no considerable effect on the HSA tertiary structure at 37oC. However, a dose 2 folds that of the therapeutic dose has a slight effect, but higher doses of the drug has a mild effect in pathological temperature (42oC). In addition, charge density of HSA surface is decreased at 42oC, compared to 37oC. Hence, this finding suggests a reduced role of HSA in regulation of osmotic pressure in the fever conditions, compared to the physiological conditions. Co-amoxiclav reduces the charge surface density of HSA at physiological and pathological temperatures and therefore alters its binding properties, which could be important in drug interference and complications.

Long-term use of indwelling medical catheters has often been hindered by catheter-associated nosocomial infections. In this study the effectiveness of silver coating of polystyrene and polyethylene polymers was investigated. Polymer pieces of 2 cm2 each were coated with a thin layer of silver using electroless plating technique. Silver-coated polymers were challenged with cultures of four different microorganisms known for their involvement in nosocomial infections in both solid and broth media. The tested bacteria included Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa. Silver release from the coated polymers was 2-5 μg/cm2 which was confirmed by chemical and biological methods. The silver coating thickness ranged between 20-450 nm. P. aeruginosa and S. aureus were the most adherent bacteria to polystyrene sheets while E. coli showed minimum adherence effect. The survival rate of different bacteria after 80 min in a time course experiment tended to dominate E. coli as the most sensitive bacteria to the effect of silver with zero survival rate while around 4% of P. aeruginosa were detected after same period. Silver coating of indwelling polymers by electroless technique seems promising in combating nosocomial infections due to long-term catheterization.

Two novel 3-amino-5-(4-choloro-2-phenoxyphenyl)-4H-1,2,4-triazole derivatives were prepared and their anticonvulsant activity was measured by evaluation of the ability of these compounds to protect mice against convulsion induced by lethal doses of pentylenetetrazole (PTZ). Diazepam (Sigma) was considered as a positive control drug with anticonvulsant effect [ED50 = 1.2 (0.5-1.9) mg/Kg]. Amongst the compounds tested, compound 3, 3-amino-5- [4-chloro-2-(2-flurophenoxy)phenyl]-4H-1,2,4-triazole, showed potent anticonvulsant activity [ED50 = 1.4 (1.0-2.2) mg/Kg] compared to diazepam.

Costus speciosus (Koen) J.E. Sm. plant and its extracts are used for treatment of fever, snake bites, jaundice, and as a purgative, astringent and antibacterial agent. In the present study, an attempt has been made to evaluate in vitro antioxidant activity of different extracts of this plant by DPPH radical scavenging activity, total antioxidant capacity, nitric oxide scavenging activity, ion chelating activity, hydroxyl radical scavenging activity and its correlation with total phenolic content.

In the developing countries of tropical regions, mycotic infections are common cause of skin diseases.The use of medicinal plants in the treatment of skin diseases including mycotic infections is an age-old practice in many parts of the world. The drugs used against dermatophytosis have several side effects, but limited efficacy. There is therefore a distinct need for discovery of new, safer and more effective antifungal agents. Medicinal plants used in traditional folk medicine may help us to overcome the growing problem of resistance to antifungal drugs and also their relative toxicity. In this study, in vitro antifungal activity of Pogostemon parviflorus leaf extracts were evaluated against three different genera of dermatophytes including Microsporum, Trichophyton and Epidermophyton, using the agar dilution method. Pogostemon parviflorus Benth. belongs to Labiatae family. The ethanolic extract of Pogostemon parviflorus leaf inhibited the growth of tested dermatophytes at different concentrations. The ethanolic extract of Pogostemon parviflorus leaf completely prevented the growth of tested dermatophytic species, with minimum inhibitory concentration (MIC) values between 2.5-10 mg/mL. The minimum fungicidal concentration (MFC) values of this plant were also in the range of 2.5-10 mg/mL. Results of phytochemical screening tests indicated that the leaf of Pogostemon parviflorus contained saponins, reducing sugars, tannins, phenols and proteins, but it did not have any glycosides, anthraquinones, alkaloids or flavonoids. Results of High Performance Thin Layer Chromatography (HPTLC) studies indicated that the ethyl acetate extract of Pogostemon parviflorus leaves included triterpenes, as 10 and 14 peaks of ultra violet (UV) absorption were observed in 254 nm and 366 nm, respectively. Hence, triterpenes may be responsible for antidermatophytic activity of this plant.

Emergence of resistance among pathogenic bacteria against available antibiotics is posing a great challenge to the current world. Thus, there is a great need to discover novel antibiotics. Traditional plants have been proved to be novel source in the search of antimicrobial compounds. The current study pertained to the susceptibilities of some clinically significant bacterial species to various crude extracts of Elettaria cardamomum Maton (Chhoti elaichi) dry fruits by agar well diffusion assay. Minimum inhibitory concentrations (MIC) of extracts were further evaluated against these bacteria. The study indicated that antibacterial activity of this plant is dependent on the type of extract and the organism evaluated. Ethanol extract was found to have comparatively higher activity than other organic and aqueous extracts. Gram-positive bacteria showed competent but variable susceptibilities to all the tested extracts. MIC data showed hopeful results as some of the extracts exhibited significant inhibitions of bacteria even at concentrations as low as 512 µg/mL. Overall, E. cardamomum seems to have significant antibacterial activity and to be very useful in the discovery of novel antibiotic.

This study was designed to examine the in vitro antioxidant activities and total phenolic contents of the methanolic extracts from male inflorescence of Salix aegyptiaca L. grown in Iran. The methanolic extract (ME) and its three fractions including water (WF), butanol (BF) and chloroform (CF) were prepared and then their antioxidant activities, as well as total phenolic contents, were evaluated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay and the Folin–Ciocalteu method, respectively. Among the different fractions of methanol extract, BF indicated the most antioxidant activity with an IC50 value of 27.7 µg/mL and total phenols of 313.8 ppm, which is comparable with the synthetic antioxidant BHT (IC50 = 26.5µg/mL). The antioxidant activities of the other fractions decreased in the order of ME >WF > CF. The potent antioxidant activity of S. aegyptiaca supported its possible use as a natural antioxidant in food industries and other pharmaceutical preparations.

The aim of this study was to provide a clinical pharmacy education program at Masih Daneshvari hospital, a University affiliated hospital, located in Tehran, Iran.For this purpose, the most common pharmacist involved interventions and aspects of potential fields for pharmacy students and residents education was firstly identified. Clinical pharmacy interventions and drug information forms were filled during the study period, from January 2006 till January 2007. Based on the results of this study, a total number of 772 interventions were conducted during the study year. Drug information had the highest rate of 22.30% among all interventions, followed by dose adjustment, and therapeutic reduction or addition. The mean number of medications per patient was 8.62 ± 7.54. In conclusion, it could be said that although in our country the challenge for the pharmacy as a profession is in its initial stages compared to the developed countries, the result of this study revealed a high demand for this service among health care providers.

Rhododendron dauricum L. is an ancient Chinese traditional herb. The pharmacological effects of R. dauricum extract have been shown in chronic tracheitis. The aim of this study was to investigate the cardiovascular effects of Rhododendron dauricum L. flavonoids (RF) on rats and its mechanisms. This study was performed in isolated vascular rings and a rat model of myocardial infarction and isolated myocytes. RF (0.5 – 4 mg/mL) induced a concentration-dependent relaxant effect on the phenylephrine (10-5 M) and KCl (60 mM) contracted aortic rings, with or without intact endothelium. This effect was attenuated by pretreated with L-NAME (10-5 M) and K+ channel inhibitor 4 - AP (1 mM) and TEA (1 mM). The Ca2+-induced contraction and PE-induced contraction were obviously attenuated after pretreated with RF (2 mg/mL) for 30 min in Krebs solution, without Ca2+, containing 10-4 mol EGTA. KCl (60 mM) significantly increased the intracellular free Ca2+ concentration ([Ca2+]i) and RF inhibited the changes induced by KCl in single cardiac myocytes. RF obviously prolonged the survival time of hypoxia mice pretreated with isoprenaline and reduced the myocardial infarction size in rat coronary artery ligation. These findings suggest that RF induces concentration-dependent vasodilation and myocardial preservation.

Nitric oxide (NO) is thought to be involved in spatial learning and memory in several brain areas such as hippocampus. This study examined the effects of post-training intrahippocampal microinjections of 1400W as a selective inducible nitric oxide synthase (iNOS) inhibitor on spatial memory, in both anesthetized and non-anesthetized situations in rats. In the present work, 4-day training trials of animals were conducted. Spatial memory was tested 48 h after the drug infusions. For microinjection of 1400W into CA1 region of the hippocampus in conscious animals, guide cannula was implanted into the CA1 area and 1400W was infused after recovery from surgical anesthesia. In anesthetized animals, 1400W was microinjected directly into CA1 region by Hamilton syringe during anesthesia. After completion of training, 1400W (10, 50 and 100 µM/side) were microinjected bilaterally (1 µL/side) and testing trials were performed 48 h after drug infusions in both groups of cannulated and non-cannulated rats. Significant reduction was observed in escape latency and traveled distance in animals that received 1400W (100 µM/side, * P < 0.05) via cannula after recovery in comparison with control group. Moreover, microinjection of 1400W (100 µM/side) in post recovery phase also caused a significant (*** P < 0.001) reduction in time and distance of finding the hidden platform in comparison with anesthetized situation. These results suggest that 1400W has a significant improvement on spatial memory, and memory enhancement induced by iNOS inhibitor can be affected by anesthesia in a period of time.

Insufficient control of post-thoracotomy pain can produce breathing dysfunction and long term staying in neonatal intensive care unit (NICU). It can increase the incidence of pulmonary complications such as atelectasis, pneumonia and respiratory failure. The aim of this study was to determine the analgesic effect of continuous extrapleural nerve block, using ropivacaine, in neonates younger than 7 days old with esophageal atersia (EA) and the incidence of atelectasis and duration of hospitalization in NICU.For this purpose, from February 2007 till January 2009 in Mofid children’s hospital, 68 neonates under 7 days old whom were candidate for thoracotomy due to esophageal atresia were, randomly divided into two groups in a controlled clinical trial. The cases received extrapleural infusion of ropivacaine 0.5% (0.1 mL/kg/h for 48 h) and controls received acetaminophen 20 mg/kg three times a day via the rectal route. Hemodynamically unstable patients and those who suffered from hospital infections were excluded from the study. After the surgery, all patients had spontaneous breathing without endotracheal tube and stable hemodynamic in NICU. Pain level was determined for each neonate, based on the neonatal infant pain scale (NIPS) grading. The incidence of atelectasis in the first 48 h after operation and throughout the NICU staying were also determined.Results showed that there were no significant difference in the mean age, sex proportions and mean weight between the two groups. The mean pain score in the group received ropivacaine (1.9 ± 0.7) was significantly less than the control group (5.2 ± 0.6) (p < 0.001).Five percent of cases (n = 1) and 100% of the control group (n=20) had pain scores equal or greater than 3 (p < 0.001). The incidence of atelectasis among cases was less than the control group (35% vs. 65% respectively; p = 0.58). Duration of hospitalization in the case group (12 ± 5.6 days) had no significant difference from the control group (13.6 ± 4.8 days) (p = 0.3)In conclusion, the results showed that continuous extrapleural infusion of ropivacaine reduces the pain noticeably and atelectasis relatively, after thoracotomy in neonates younger than 7 days suffering from EA, compared to the acetaminophen group.