The Study Of The In-situ Ginkgo Biloba L Gel For Intranasal Administration

GBE is the extract of the Ginkgo biloba leave, in which there are two main components total flavonol glycosides (TFG) and terpenes. Quercetin, Kaempferol and Isorhamnetin are the three main flavones, which have a significant effect of the cardio-cerebral vascular diseases, high blood lipids, high blood pressure and scavenging oxygen free radicals. Terpenes are including Ginkgolide A(GA), Ginkgolide B(GB), Ginkgolide C(GC), Ginkgolide M(GM), Ginkgolide J(GJ) and Bilobalide(BB), which are potent platelet-activating factor(PAF) antagonist can reduce blood viscosity and improve blood flow. Recent studies have shown that GBE can improve the cognitive dysfunction and treatment of senile dementia.Senile dementia refers to the old age has been emerging, in essence, sustained damage that is caused by organic brain damage largely irreversible loss of intelligence and reduced ability to the social adaptation. Its pathogenesis is very complex and may be related to cholinergic and monoamine energy, neuropeptides and other neurotransmitters and modulation compounds dysfunction.At present the clinical route of administration is oral and injection. However, the oral administration is convenience, which results in low bioavailability and first-pass effect. Subcutaneous injection is pain which is also inappropriate self-medication. Th-erefore, the development of an effective and convenient route of administration is an option to increase the concentration of the brain and enhance the therapeutic.Intranasal drug delivery system(INDDS) is one of the most heated research topics in the recent years with the advantages of rapid absorption, low first-pass effect and good compliance. And the route is also found to be useful to directly delivery drug to the brain, which is expected to increase the brain concentration of GBE to enhance the control effect on Alzheimer's. In traditional Chinese medicine, liquid nasal drop is the main dosage form of intranasal administration. Because cilia movement and mucus movement on nasal mucosa, there are short time for drug to stay on nasal mucosa and low bioavailability of drug. Therefore, the aim of this topic is mainly exploration of the preparation method of in-situ GBE gel for intranasal administration, and study of the effect of sorbefacients on nasal mucosa absorption and evaluation of its pharmacokinetics, so as to provide a more effective formulation for clinical GBE application.Main research contents:1 To establish in vitro analytical methods of GBEA reversed-phase HPLC analysis was developed to determine TFG in GBE. Agilent C18 was selected as the column; mobile phase consisted of methanol and 0.4% phosphoric acid solution (50:50, v/v); the flow rate of 0.80 mL·min-1; UV detection wavelength was 360 nm and column temperature was 30℃.A HPLC-ELSD analysis was developed to determine four terpenelactones in GBE. Bartlett C18 was selected as the column; mobile phase consisted of Methanol: tetrahydrofuran:water (25:10:65, v/v); the flow rate of 0.60 mL·min-1; The carrier gas (N2) flow rate of 2.7 L·min-1; column temperature was 30℃; Drift tube temperature was 115℃.2 Prescription screening of the in-situ GBE gel for intranasal administrationScreening vehicle of in-situ gel from gellan gum, Carbopol 934 and HPMC were used as gel matrix to prepare in-situ GBE gel for intranasal administration, which showed that 0.8% of Carbopol 934 and 1.5% of HPMC were the best. GBE was very slightly in the water. In this study, phase solubility method was used to study the GBE at different volume fraction of HP-β-CD. Screening principle of other reagents were little toxicity to nasal cilia and without impact to stability of the drug.3 The Study of the Preparation Method of the in-situ GBE gel for intranasal administrationAt room temperature taking GBE 4.5 g, adding distilled water which had been redissolved with the HP-β-CD solution, then constantly stirring dissolved. And added the other components of the prescribed dosage, stirring dissolved. Adding 1.5 g HPMC, so that hydration swelling, and then dissolved in 0.8 g Carbopol 934 which stirred about 24 h. With 1 mol·L-1 of the NaOH adjusted pH to 4.3.4 Study of the effect of sorbefacients on nasal mucosa absorptionTaken in vitro goat nasal mucosa as material, and 1% of Azone,1% of Twain-80 and 0.5% of Borneol as sorbefacients, and the experiment was carried out in Franz diffusion cell. Three sorbefacients were studied. The sequence of their permeation rate were 1% of Azone>1% of Twain-80>0.5% of Borneol. The drug absorption rate increases as the Azone concentration increases, the process of which fits Weibull equation.5 Safety evaluation of the in-situ GBE gel for intranasal administration The safety of the in-situ GBE gel for intranasal administration and accessories were studied. The optical microscope observation of in situ toad palate model was employed to investigate ciliary movement of the in-situ GBE gel for intranasal administration and accessories. The results showed that the in-situ GBE gel for intranasal administration and accessories had no toxicity to mucosa-ciliary movement.6 The study of the stability of the in-situ GBE gel for intranasal administrationPreliminary study on stability of 3 batches of samples was carried out including heat test, light test and high humidity test. It showed that the product could be stored in room temperature.7 Pharmacokinetics study of the in-situ GBE gel in rabbitA HPLC analysis was developed to determine quercetin concentration in rabbit plasma. Agilent C18 was selected as the column; mobile phase consisted of methanol and 0.4% phosphoric acid solution (60:40, v/v); UV detection wavelength was 368 nm and sample volume was 20μL. According to the method evaluation, it showed that good extraction recovery, method recovery and precision. Pharmacokinetics of the in-situ GBE gel in rabbit was studied by oral and nasal administration of in-situ GBE gel by double preparation and double periods. Pharmacokinetics parameters were caculated. The results of pharmacokinetic study indicated that nasal spray fit with one compartment model in vivo. And Tmax 1.22 h; Cmax 779.30μg·L-1 in in-situ GBE gel; Tmax 1.92 h, Cmax 452.79μg·L-1 in Ginkgo Biloba L tablets; the relative bioavailability was 77.52%. Conclution:GBE was used to prepare pH sensitive in-situ gel for intranasal administration. In the research it showed that coherent formulation, viable technique process, ease control of quality, excellent of release, good stability, little ciliotoxicity and quick absorption.