Preparation Of Patchouli Alcohol Solid Dispersion Pellets And Its Protective Effects In Lipopolysacchar Ide-induced Acute Lung Injury

Preparation of patchouli alcohol solid dispersion pelletsObject ivePatchouli alcohol (PA), a tricyclic sesquiterpene, is a major liposoluble bioactive constituent extracted from Pogostemon cablin. It is readily soluble in organic solvents and lipids but practically insoluble in water, which could be the rate determining step for poorly water-soluble active pharmaceutical ingredients’efficient absorption.In the present study, we investigates the possibility of using poloxamers as solubility and dissolution rate enhancing agents of poorly water soluble bioactive constituent PA that can be used for the preparation of solid dispersion (SD) pellets formulation.MethodsThe effect of two poloxamers (P188and P407) and their combination as dispersing carries on the dissolution rate of PA solid dispersion pellets were explored. And the establishment of a simple, accurate in vitro dissolution test method for volatility drug was also evaluated. Differential scanning calorimetry (DSC) and Fourier transform Infrared spectroscopy (FTIR) were used to explore the characteristic of PA-SD pellets and demonstrate the value in preparing eutectic systems for improving the dissolution rate of PA.Results(1) The resultant PA-SD pellets characterized by perfect appearance and high smooth roundness. (2) The disintegration time for all formulations of PA-SD pellets was within the range of8-96min. The incorporation of P188in PA/P407bSD pellets could significantly decrease the disintegration time.(3) Open in vitro dissolution test procedures gave lower results compared to the closed one. There were statistically significant difference.(4) PA powders exhibited a poor dissolution rate with only5%drug dissolved after180min. Nevertheless, it was observed that the dissolution rate was increased by approximately16times in bSD pellets with poloxamers in comparison with pure PA within180min.(5) A faster dissolution rate of PA was achieved with the incorporation of P188in PA/P407bSD pellets compared to binary PA/P407systems at different ratios within180min.(6) The dissolution rate of PA in ternary systems was directly proportional to the content of P188within30min. However, after30min the dissolution rate of PA decreased at higher level (after1/5/1ratio). P188always existed in an amphiphilic structure, which possessed the properties to self-assemble into micelles in aqueous solution when the concentration was above the critical micellar concentration (CMC). PA might be entraped by micelles formed by poloxamers, which became an obstacle to its further dissolution.(7) The melting point of PA, P188and P407were54.37℃,50.86℃and54.30℃respectively. Concerning the solid dispersions, as the amount of PA increased, endothermic peaks shifted to lower temperature and then increase. While the endothermic peaks of physical mixtures of PA and poloxamers were almost unchanged irrespective of the ratios of PA and poloxamers. The melting point of PA/P188, PA/P407and PA/P407/P188solid dispersions were lower than each pure constituent.(8) The spectra of SDs and physical mixtures were largely similar to the addition spectra of individual components, new peak was not observed other than characteristic peaks of PA and poloxamers at FTIR spectrum of PA/poloxamers composite. This suggested that there was no chemical interaction between PA and poloxamers.ConclusionThe obtained results indicated that poloxamers P188and P407were suitable for the preparation of SD pellets with PA by the low temperature melting method. bSDs with either P188or P407had significantly increased the dissolution rate of PA, with P188showing a greater dissolution rate enhancement and P407having a better solubilization capability. As compared to the use of P407alone, the incorporation of P188in PA/P407bSD pellets could strongly enhance the dissolution rate of PA. The described method for pellets preparation might find application in the manufacturing and scaling-up of solid dispersion formulations in the future. Moreover, the established closed in vitro dissolution test method is simple, accurate for assessing volatility drug dissolution. Part twoPathouli alcohol protects against lipopolysaccharide-induced acute lung injury in miceObjecti veIn our previous studies, we have found that PA could inhibit LPS-induced inflammatory responses in lipopolysaccharidc (LPS)-stimulated RAW264.7macrophages, and also possessed potent anti-inflammatory activity in animal models of inflammation. Oral administration of PA appears to be able to augment protection against IFV infection in mice via enhancement of host immune responses, and attenuation of systemic and pulmonary inflammatory responses. Additionally, pretreatment with PA attenuated the ROS generation against A β:35-induced toxicity. These findings indicate that PA possesses anti-inflammatory and anti-oxidative activities. However, few studies reported the effects of PA on LPS-induced acute lung injury (ALI) in murine model. It still remains unclear whether PA has protective effects on LPS-induced ALI in mice. Therefore, the aim of this study is to investigate the effects and possible mechanisms of PA on LPS-induced ALI in mice.MethodsThe lung wet/dry weight (W/D) ratio were determined to evaluate the protective effects of PA on LPS-induced lung edema. Sections were stained with hematoxylin and eosin, examined and photographed using Inverted Microscopes.Protein levels in BALF were measured using a Bradford-based protein assay. Levels of MPO、SOD、GPx and MDA in the lung tissue were examined by respective assay kits in accordance with the instructions of manufacturer. Activities of pro-inflammation cytokines TNF-α and IL-6in BALF were examined using enzyme-linked immunosorbent assay (ELISA) Kit.ResultsThe results showed that pretreatment with PA significantly increased mice survival rate, attenuated histopathologic damage and lung edema, and decreased the protein content in BALF of mice with ALI. Moreover, PA significantly inhibited the expression of pro-inflammatory cytokines involving TNF-a and IL-6in BALF, down-regulated the levels of MPO and MDA, and up-regulated the activities of SOD and GPx in lung tissue.ConclusionThe present study revealed that pretreatment with PA improved survival rate of LPS-induced ALI mice. The potential mechanism of this action may attribute at least partly to attenuate inflammatory responses and oxidative stress. These experimental results suggest that PA may be a potential beneficial agent for ALI.