Pharmacokinetic study of niosome-loaded insulin in diabetic rats

Encapsulation of human insulin in lipid vesicular systems such as niosomes was sought as a route to protect this protein against proteolytic enzymes and to improve its oral bioavailability The purpose of this study was to assess the effect of insulin encapsulation in niosomes on oral bioavailability in diabetic rats. Recombinant human insulin was entrapped in multilamellar niosomes composed of polyoxyethylene alkyl ether surfactants [Brij 52 and Brij 92] or sorbitan monostearate [Span 60] and cholesterol. The amount of insulin released in simulated intestinal fluid [SIF] and simulated gastric fluid [SGF] were measured at 37°C. The protection of entrapped insulin against pepsin, a-chymotrypsin and trypsin were evaluated in comparison with free insulin solution. Diabetes was induced by IP injection of streptozotocin [65 mg/kg] in male wistar rats and effects of orally administered niosomes and subcutaneously injected insulin on hypoglycemia and elevation of insulin levels in serum were compared. The extent and rate of insulin release from Brij 92 and Span 60 vesicles were lower than that of Brij 52 niosomes [P<0.05]. Vesicles protected insulin in comparison with free insulin solution against proteolytic enzymes [P<0.05] significantly Animals treated with oral niosome-encapsulated insulin [100 lU/kg] showed decreased levels of blood glucose and elevated serum insulin, which in the case of Brij 92 niosomes, hypoglycemic effect was significant [P<0.05]. Niosomes were also stable in solubilizing bile salt solutions and could effectively prolong the release of insulin in both SGF and SIF. Results of this study showed that niosomes may be utilized as oral carriers of insulin; however, to increase bioavailability of insulin, further studies on the protease inhibitor co-encapsulation in niosomal formulations might be helpful

effect of vehicles on spray drying of rifampicin inhalable microparticles: in vitro and in vivo evaluation

The aim of this study was to evaluate the effect of solvents used in the spray drying and the aerodynamic properties of the rifampicin microparticles and pulmonary absorption of the microparticles. Different mixtures of dichloromethane and water were used as solvents for spray drying of rifampicin microparticles. The water to dichloromethane ratios were 25:75, 50:50, 75:25, 80:20, 90: 10 and 100:0. The solutions were dried at inlet temperature of 70 °C. The powder properties of the samples were examined by laser diffraction, scanning electron microscopy [SEM], helium densitometer and infrared spectroscopy [IR]. The aerosolization performance of these formulations was investigated using an Andersen cascade impactor. Pulmonary absorptions of formulations were examined by the in situ pulmonary absorption described by Enna and Schanker method. The plasma concentration time profiles of rifampicin were constructed 8 hours following the intravenous and the intrapulmonary administrations. The pharmacokinetics parameters, C[max], T[max], t[1/2] AUC, mean residence time [MRT], K[a] and K[e] were determined for each formulations. The T[max] values for the samples decreased by increase in the amount of water in the initial feed. The T[max] values for the spray dried samples from the different mixtures of dichloromethane and water were 60 [min] and 30 [min] respectively. The solvent mixture as the spray drying vehicle played an important role in the in vitro and in vivo lung deposition. The type of spray drying vehicle showed significant effect on the aerodynamic behavior and pharmacokinetic parameters of the particles. The pulmonary absorption of drug revealed the possibility of achieving the minimal inhibitory concentration [MIC] of the antibiotics. The spray drying vehicle only affected absorption patterns of the formulations and it did not have any effect on the elimination rat of particle

Comparison of super critical fluid extraction and hydrodistillation methods on lavander's essential oil composition and yield

Lavender's essential oil is commonly used in aromatherapy and massage. Its major clinical benefits are on the central nervous system. Linalyl acetate and linalool are the most predominant chemical constituents in the essential oil of Lavandula angustifolia Comparison of super critical fluid extraction [SCFE] and hydrodistillation [HD] methods on Lavander?s essential oil composition and yield methods In this work we extracted essential oil of this plant with two different methods; SCFE and HD and further analyzed by GC and GC-MS method. seventeen compounds were identified in the oil which prepared by HD, the major components of them were j. pinene [35.9%] and lavandulyl acetate [14.1%]. In the SCFE extracted sample, the most frequent components were linalyl acetate [73.5%] and lavandulyl acetate [7.5%]. According to obvious difference in the composition of the essential oils prepared by two different methods [SCFE and HD], it seems that extraction method differ chemical composition of the oil and probably affects pharmacological properties