Studies On Panax Notoginseng Saponins Nasal Spray

The objective of this research project is to develop nasal sprays of Panax notoginseng saponins (PNS) and investigate their biocompatibility, pharmacokinetic and pharmacodynamic characteristcs, in order to provide new, effective and user-friendly pharmaceutical preparations for clinical use. The 4 main parts were:(1) establishment of analytical method for ginsenoside Rbl (Rbl) and Rgl (Rgl), the most abundant active components in PNS, in in vitro and in vivo samples; (2) investigation on the preparation technique, formula screening and optimization of PNS nasal sprays; (3) pharmacokinetic study of the nasal sprays in rabbits and pharmacodynamic evaluation of their protective effects against acute myocardial infarction in rats; (4) assessment of quality and stability of the nasal sprays.RP-HPLC method was used to analyze Rbl and Rgl content in in vitro samples. The linearity range between concentration and peak area for both Rbl and Rgl was 0.2-50μg/ml, with a coefficient of 0.9995. Both within-day and between-day precision were less than 2% for Rb1 and Rgl. Recovery of Rbl and Rgl from PNS nasal sprays were in the range of 95%-105%. Serum samples were pretreated with solid phase extraction cartridges and analyzed by HPLC. Results indicated that Rbl established good linear relationship between concentration and their peak area in the range of 1.0-60μg/ml, while the linearity range for Rgl was 0.5-60μg/ml. The coefficient for both was 0.9999. Recovery of Rbl and Rgl were both in the range of 90%-105%, while extraction recovery was over 75%. Within-day and between-day precision were less than 10% for Rbl and Rgl. Therefore, the analytical method is suitable for the aims of analyzing in vitro and in vivo samples.In order to prolong the drug retention time on nasal mucosa, bioadhesive polymers, namely deacetylated gellan gum, Carbopol 940, and Carbopol 971P, were added to the nasal sprays. Formula screening and optimization were carried out by studying the viscosity, rheological properties and in vitro drug release characteristics. The effect of the excipients on such parameters of the nasal sprays was investigated, and a proper preservative was selected. The preparations gave pseudo-plastic behavior in rheological studies, i.e. viscosity decreased remarkably with increasing shear rate, thus indicating non-Newtonian flow. Drug release profile of the nasal sprays fitted Ritger-Peppas equation well, suggesting an anomalous drug release behavior corresponding to a combination of diffusion and relaxation. Ciliotoxicity study using in situ toad palate model showed that cilia movement after administration of nasal sprays lasted for over 81% that of normal saline, revealing minimal ciliotoxicity. Rabbit eye model study demonstrated no significant mucosal irritation.Pharmacokinetic profile of PNS nasal sprays on rabbits conformed to a two compartment model. Rb1 and Rg1 were well absorbed from nasal mucosa, and the absolute bioavailability of Rb1 was significantly superior to intranasal solution, almost twice the value of intranasal solution. Moreover, the bioavailability of 0.5% deacetylated gellan gum and 0.15% Carbopol 971P preparations were comparable to that of intravenous injection. For the pharmacodynamic study which investigated the protective effects of the nasal sprays against cardiovascular diseases, we built the acute myocardial infarction model in rats by occlusion of left anterior descending coronary artery. As a result, PNS-0.15% Carbopol 971P nasal spray significantly reduced myocardial infarct size, and the effects were dose-dependent, i.e. the higher dose used, the better effects obtained. Rat ciliotoxicity study revealed no marked damage on nasal mucosa.We assessed the integrity, dose per actuation, and other requirements listed in the Chinese Pharmacopeia of the metered nasal spray devices, and the devices passed all the tests. We performed the influencing factors test, accelerated and long term testing for stability in accordance with the Chinese Pharmacopeia and ministerial standard. Quality assessment criteria include appearance, pH, TLC and RP-HPLC, and a quality specification protocol were developed. After dilution, Rb1 and Rg1 concentration in samples were determined by HPLC, resulting in a recovery of 95%-105%, and within-day and between-day precision of less than 5%. Results from influencing factors test showed instability under high temperature, high humidity and strong light, and hence the nasal spray should be stored in a cool dry place, and away from light. Accelerated and long term stability testing showed no significant changes in quality after storing under the condition of 40℃±2℃and RH75%±5%, as well as 25℃±2℃and RH40%±10% for 3 months. Results at 6 months for accelerated testing, and results at 6,9,12,18,24 and 36 months for long term testing are under way.Based on the above results, it can be concluded that PNS-0.15%Carbopol 971P nasal spray has successfully achieved the objectives of the research project. Not only did the nasal spray extend the retention time on nasal mucosa, increase drug absorption, and enhance bioavailability, but also exert minimal ciliotoxicity and irritation on nasal mucosa. Quality control was effective, and stability test also demonstrated satisfactory results.