Studies On Donepezil Hydrochloride Nasal Thermosensitive In Situ Gel And Its In Vivo Pharmacokinetics And Brain Targeting In Rats

Objective Donepezil hydrochloride is the second generation of highly selective acetylcholinesterase inhibitors,mainly used in the treatment of mild and moderate Alzheimer's disease,with strong pharmacological activity,high selectivity,fewer adverse reactions and good tolerance.DPZ has been listed in tablets and capsules.DPZ oral preparation has gastrointestinal side effects.Moreover,because of its strong hydrophilicity,it is not easy to penetrate the blood-brain barrier.Little drug enter brain tissue.And the curative effect is affected.The advantages of intranasal administration are fast absorption,high bioavailability and brain targeting.Therefore,in this paper,DPZ was used as a model drug to prepare the nasal thermosensitive in situ gel for the purpose of rapid absorption,high bioavailability,convenient use,and brain targeted drug delivery.In this paper,a systematic and in-depth study of DPZ nasal thermosensitive in situ gel was conducted from the aspects of pre formulation preparation,in vitro transdermal study,prescription selection of nasal thermosensitive in situ gel,preparation process,in vitro quality evaluation,pharmacokinetics and bioavailability in vivo,targeting of the brain and nasal cilium toxicity.Method In the first Chapter,in the pre formulation study of DPZ thermosensitive in situ gel,the HPLC method was established for the determination of drug content.And the three aspects including the oil and water partition coefficient,the chemical stability of the solution and the solubility of the water-soluble derivative of?-CD were completed.The results showed that when the buffer pH was less than 4.0,the P value of DPZ was far less than 1.When the buffer pH was greater than 4.0,the P value increased gradually with the increase of the buffer pH.DPZ was stable in neutral conditions,poor in acidic and strong oxidation conditions,and the worst in strong alkaline pH conditions.When the pH value was 7,the chemical stability of DPZ solution was the best.When the pH value was less than 7,the chemical stability of DPZ solution decreased.When the pH value was more than 7,the chemical stability of DPZ solution decreased significantly.In addition,the greatest solubilization effect on DPZ was HP-?-CD,while the better solubilization effect on DPZ was DM-?-CD and its solubility was reduced by SBE-?-CD.Finally,the chemical stability of DPZ solution was not affected by the ionic strength.In the second chapter,in vitro transdermal experiments of DPZ,the effects of DM-?-CD,SBE-?-CD and HP-?-CD on the penetration of DPZ and the concentration of penetration enhancers on the penetration of DPZ were investigated and compared.The results showed that the penetration of DPZ was promoted by three kinds of derivatives of?-CD.The best effect was promoted by HP-?-CD,and when the concentration was 3.5%,it had the best effect.Therefore,3.5%HP-?-CD was chosen as the absorption enhancer for DPZ nasal thermosensitive in situ gel.In the third chapter,prescription screening and preparation technology of DPZ nasal thermosensitive in situ gel were studied.Star-point design-response surface methodology was used to design two-factor five-level experiment.Taking poloxamer 407?F127?and poloxamer 188?F68?as factors,and gelation temperature and gelation time as screening indexes,the optimum prescription conditions were screened out as 19.64%F127 and 8.2%F68.Then,according to the results of the first chapter on the DPZ oil and water partition coefficient and the chemical stability of the solution,the pH value of DPZ in situ gel was initially set to 7.According to the results of the second chapter DPZ transdermal test in vitro,3.5%HP-?-CD was selected as the absorption enhancer for DPZ thermosensitive in-situ gel.Secondly,the optimal formulation and preparation process of the preparation were determined.The formulation of DPZ thermosensitive in situ gel was 5%DPZ,3.5%HP-?-CD,and 0.05%ethyl paraben,19.64%F127,8.2%F68,and solvent as water.In the fourth chapter,in vitro quality evaluation of DPZ thermosensitive in situ gel was carried out.3 batches of DPZ thermosensitive in situ gel samples were prepared.The appearance,pH,gelatinization temperature,gelatinization time,dissolution rate and in vitro release rate of DPZ thermosensitive in situ gel were investigated.The in vitro dissolution rate of DPZ thermosensitive in situ gel in 45min was 88.40%.And the drug release rate was89.28%.When the temperature sensitive in situ gel was more dissolved,the drug release was more complete.The linear relationship between the two groups was obvious?r=0.991?.In the DPZ release test,the release rate of DPZ solution was very fast,and the cumulative release was as high as 85%within 2 h.The drug release temperature of nasal thermosensitive gel was slightly slower,the cumulative release was less than 50%at the same time,and the cumulative release of 8 h was only 70%,indicating that the DPZ nasal thermosensitive gel is good sustained release.The quality of DPZ nasal thermosensitive in-situ gels showed that the appearance of 3 batches of samples was transparent and clear,and the pH values were all about 7.The contents of DPZ and ethyl paraben were all within the range of 95%¹05%.In the fifth chapter,the pharmacokinetics of DPZ thermosensitive in situ gel was investigated.First,the HPLC-fluorescence detection method of DPZ concentration in rat plasma was established.Then,the plasma concentration of DPZ nasal thermosensitive in situ gel was determined by nasal administration,using intragastric administration as a reference.The pharmacokinetic parameters of T_max,C_max,AUC and relative bioavailability?F_r?were calculated by 3P97 pharmacokinetic program.The results showed that the T_max,C_maxax and AUC_0-?of DPZ nasal thermosensitive in-situ gel were 0.17 h,4113.41ng·mL^-1,3010.10ng·h·mL^-1,respectively,while the T_max,C_maxax and AUC_0-?of intragastric administration were 0.92 h,269.35ng·mL^-1,780.66ng·h·mL^-1,respectively.The F_r of DPZ nasal thermosensitive in situ gel is as high as 385.58%.The results showed that DPZ absorbed more rapidly and its bioavailability increased significantly after intranasal administration.In the sixth chapter,the brain targeting of DPZ thermosensitive in situ gel was studied.First,a HPLC fluorescence detection method for determining the concentration of DPZ in rat brain tissue was established.Then,the drug concentration of the different brain tissue,such as the olfactory bulb?OB?,the olfactory tract?OT?,brain?CL?and the cerebellum?CR?of the rat were determined after administration of DPZ nasal thermosensitive in situ gel,using intragastric administration as reference.It was found that the main pharmacokinetic parameters,such as T_max,C_max,AUC_0-?of intranasal administration were0.23h,11218.3434ng·g^-1,8832.22ng·h·g^-1,respectively,and T_max,C_maxax and AUC_0-?of intragastric administration were 1.5 h,757.85 ng·g^-11 and 1581.32 ng·h·g^-11 respectively.There was a significant difference between them?P<0.05?.The brain targeting index of DPZ nasal thermosensitive in situ gel was 1.51,indicating that it had obvious brain targeting.In the seventh chapter,in the study of nasal mucociliary toxicity of DPZ thermosensitive in situ gel,toad palate mucosa model was used in vitro and in vivo to evaluate its ciliary toxicity.The ciliary toxicity of DPZ solution,blank prescription and intact prescription to nasal mucosa was investigated.The results showed that DPZ solution,complete prescription and blank prescription had certain toxicity to nasal mucosal cilia,but the toxicity was reversible.Among them,the toxicity to nasal mucosal cilia were in the order:DPZ solution>complete prescription>blank prescription.