The Study On 3-n-butylphthalide Nasal In-situ Gel Preparation

Objective: 3-n-butylphthalide(NBP)is a common clinical drug for the treatment of stroke,and its commonly used oral method has low bioavailability,and its intravenous injection or infusion method requires professional medical personnel to operate,which having limitations.Therefore,the study aims to explore a suitable administration route and reasonable dosage form of NBP,so as to increase the concentration of NBP reaching the brain target and improve the bioavailability of NBP.The complex and ingenious physiological structure and effective protective mechanism of the nasal cavity provide a nasal administration system that can bypasses the blood-brain barrier and non-invasively targeted to the brain,providing a possibility for the treatment of stroke.Therefore,in this project,we develop a NBP in situ gel based on poloxamer 407(P407)and gellan gum(GG)for Nasal administration system.This system can be administrated as nasal drops and convert to gel due to the nasal physiological environment and possess bioadhesion properties,prolonging the nasal retention time.The quality,safety and efficacy of the preparation were studied to provide experimental basis for the development of NBP nasal dosage form and preliminary efficacy research basis in the treatment of stroke.Method:(1)NBP-HP-?-CD was prepared.The content of NBP was determined by Ultraviolet spectrophotometer.The validation of inclusion was verified by infrared and ultraviolet spectroscop.The phase solubility experiment was carried out.The thermodynamic characteristics of P407 and the ion-sensitive phase change characteristics and the viscosity of GG were investigated.(2)Through pre-prescription research and theoretical analysis,three factors including P407,GG and HPMC were selected.The gelatinization temperature,initial viscosity of the system and the viscosity after the system reaction with artificial nasal fluid(ANF)were chosen as indicators.A Box-Behnken design was used to optimize the preparation process for the optimal prescription.A method for the determination of NBP in gel was established.And then we investigate the release of NBP in gel in vitro.(3)Using toad jaw mucosal cilia experimental to evaluate the safety of preparation.(4)Middle cerebral artery occlusion model(MCAO)was established in SD rats,and the effect of the preparation on stroke was preliminarily evaluated by neurobehavioral score and cerebral infarction area.Results:(1)The inclusion compound of NBP-HP-?-CD with a drug load of 5.92% was prepared.It was verified that NBP and HP-?-CD produced a combination of a new phase rather than a simple one.The apparent stability constant of NBP-HP-?-CD was 246.86.The preparation technique of NBP-HP-?-CD can effectively improve solubility of NBP.Other ingredients in the prescription contributed variously to P407 gel formation process.HP-?-CD can increase the gelatinization temperature.HPMC lowers its gelatinization temperature,while GG has little effect on it.When the ANF was the same in the solution system,with the increase of GG concentration,the gelatinization of system becomes fast and the water holding capacity is enhanced.When the volume ratio of GG to ANF is 8:2,the gelatinization becomes the fast and the water holding capacity is the strongest.Other ingredients in the prescription contributed variously to viscosity of GG.P407 and HPMC could increase the viscosity of GG solution or gel.HP-?-CD reduces the viscosity of the GG solution,but it increases the viscosity of the GG gel.(2)The optimal prescription was 15.01%P407,0.2%GG,0.62%HPMC,and 20%NBP-HP-?-CD,and the solution pH value is 6.The in situ NBP nasal gel was prepared.Its in vitro drug release behavior follows the dissolution firstly and then diffusion mechanism later.(3)In the results of cilia toxicity test,compared with the normal saline group,except for the positive control group and NBP group,the mucosal cilia in each group continued to oscillate for 30-50 min and then stopped oscillating after administration.They will restore swinging and last for long time after rinsing clean with physiological saline.No ciliary loss occurred during this period,in which the higher the concentration of P407,the larger the LTCM;the larger the concentration of GG and NBP-HP-?-CD,the smaller the LTCM,indicating that the gel and its main components had different effects on nasal cilia after nasal administration,but the toxicity was small and transient reversible,and the in situ gel can effectively reduce the damage of NBP to nasal mucosa.In the effect of cilia delivery rate test,each group was significantly different from the control group(P<0.01),NBP nasal in situ gel group show good adhesion.(4)The neuro behavioral scores and percentage of cerebral infarct size in the NBP nasal in situ gel group were significantly different from those in the model group(P<0.01),while the NBP solution group was also significantly different from the model group(P<0.05),indicating that NBP nasal in situ gel and NBP solution can improve neurological symptoms and reduce the area of cerebral infarction,but NBP nasal in situ gel is better.Conclusion: The gel preparation technologyl is reasonable and reliable,and meets the requirements of nasal administration.It has little irritation to nasal mucosa,and has potential value in the prevention and treatment of stroke,which is worthy of further research.