Study On The Absorption Of Montelukast Sodium Via Rectal And Nasal And The Effects Of Enhancers On It

Background and objectivesAs a common allergic reaction,asthma is caused by many factors.The clinical treatment of asthma usually use LABA,ICS,theophyllines,anticholinergics etc,inhalation via the respiratory tract or oral administration was applied.Asthma incidence in our country has the same upward trend that the morbidity of children is higher than adults.Our country has a huge number of children,and draws more and more attention today.Therefore paying attention to preparation administrated to children has become a trend;in recent years,our countries issued relevant documents about childrens medication.It also means there will be more pharmaceutical makers designed for appropriate drug dosage forms in children's particular need.And medication for children will be supported and popularized.the commonly used dosage forms of administration for children include: dispersible tablets,chewable tablet,effervescent preparation,granulesetc.While these preparation is not suitable for infants and children to swallow and has poor compliance.Transrectal administration,as an important way of clinical administration,is especially suitable for children who have difficulty in swallowing,patients with mental diseases and comatose patients.It is characterized by convenient administration,effectiveness,no trauma after administration,and a role in local or systemic treatment.The rectum has rare folds and no villus,and is empty under normal circumstances.Therefore,drug absorption is rarely influenced by other intestinal contents.Meanwhile,there is an inferior rectal vein which bypasses the liver and directly enters the systemic circulation via the internal iliac vein,avoiding first-pass effect.Thus,the rectum is the ideal part of drug absorption.Also,transrectal administration can avoid the degradation of drug molecules caused by gastric acid and various gastrointestinal enzymes,improve bioavailability,and avoid drug stimulation to the gastrointestinal tract.After transrectal administration,the speed and extent of action of the drug also depend on physical and chemical properties,dosage form and prescription of the drug.At present,common rectal preparations include suppository,micro enema and gels,etc.Transnasal administration is also an important way of clinical administration,and characterized by no first-pass effect,convenient administration,effectiveness,good compliance,and acceptability in infants and children.The main area for transnasal drug absorption is located in the upper nasal mucosa.Considerable villus exists in the nasal mucosa,contributing to greatly enlarged effective surface area for drug absorption.Due to rich capillaries and lymphatic networks in the mucosa,the drug can penetrate into the blood and tissues,and immediately enter the systemic circulation and brain via vascular wall.Some drugs with high water-solubility are difficult to be absorbed in the gastrointestinal tract;while transnasal administration can improve bioavailability and reduce toxic side effects.Transnasal preparations mainly include nasal drops,nasal spray,etc.Montelukast sodiumis an anti-asthmatic drug,and its common dosage forms of administration include tablet,granules,etc.However there has no rectal administration,combined with drug absorption characteristics of transrectal and transnasal administration,asthma symptoms may be rapidly relieved.So as to evaluate the rectal absorption profile of montelukast sodium in comparison with the intravenous administration group to provide evidences for the studies on the rectal,nasal formulations of montelukast sodium.Methods1.Establishment of determination method for montelukast sodium concentration in bloodAn HPLC and fluorescence method for determining blood concentration of montelukast sodium in rabbit was established.To investigate the precision,accuracy and stability of the determination,and evaluate the feasibility of this method which can provide the basis for later experiment.Reference solution of montelukast sodium are dissolved and diluted with methanol into a series of standard reference solution,then diluted with blank plasma into a series of standard solution.According to proposed plasma sample processing method and chromatographic condition to analyze and prepare standard curve,then to apply proposed lower limit of quantification,low,medium,high concentration to prepare plasma sample and processing.Investigate the evaluation index of the method such as precision,accuracy and stability.2.Investigation on bioavailability of montelukast sodium transrectally and transnasally administrated.Choose rabbits fasted for 24 h,and with intravenous injection as control,at a dose of 50 mg/kg and 10mg/kg to investigate the bioavailability of montelukast sodium via rectal and nasal administration.Blood was collected via auricular vein at 0.17,0.33,0.50,1.00,2.00,3.00,5.00,7.00 h and 1,3,5,10,20,30,45,60,90,120,180 min after rectal and nasal administration,according to aforementioned method to determine the plasma concentration.Using pharmacokinetic data statistics software DAS3.1.6 to calculate and analyze pharmacokinetic parameters,calculate bioavailability by the formula,Frectal=AUCrectal/ AUCinject,Fnasal=AUCnasal/AUCinject.3.Study on effect of different enhancers on absorption of montelukast sodium via rectal administrationAccording to the results of preliminary experiment,sodium caprate,Tween-80,laurocapram,sodium cholate,L-arginine,sodium laurate,2%chlorpromazine,1%EDTA-2NA were selected for the preparation of enema with montelukast sodium at a dose of 50mg/kg in rabbits fasted for 24 h.Blood was collected via auricular vein at 0.17,0.33,0.50,1.00,2.00,3.00,5.00,7.00 h after rectal administration,according to aforementioned method to determine the plasma concentration.concentration-time curves were obtained with 5 rabbits for parallel determination at each concentration.Using pharmacokinetic data statistics software DAS3.1.6 to calculate and analyze pharmacokinetic parameters,and evaluate the enhancing absorption effect of absorption enhancers.4.Study on effect of different enhancers on absorption of montelukast sodium via nasal administration.Different type of absorption enhancer sodium caprate,Tween-80,sodium cholate were selected for the preparation of nasal drops with montelukast sodium.At a dose of 10mg/kg in rabbits fasted for 24 h,blood was collected via auricular vein at1,3,5,10,20,30,45,60,90,120,180 min after nasal administration,according to aforementioned method to determine the plasma concentration.Concentration-time curves were obtained with 5 rabbits for parallel determination at each concentration.Using pharmacokinetic data statistics software DAS3.1.6 to calculate and analyze pharmacokinetic parameters,and evaluate the enhancing absorption effect of absorption enhancers.The main results:Establishment of determination method for montelukast sodium concentration in blood1.1 Standard curve: in the concentration range of 0.1¹0?g/m L,montelukast sodium presented a good linear,r=0.9998.1.2 PrecisionPrecision for intra-day: at lower limit of quantification,low,medium and high concentration of 0.1,0.2,1,8?g/m L,RSD respectively are 7.70%,5.05%,1.97%,3.65%.Precision for inter-day: at lower limit of quantification,low,medium and high concentration of 0.1,0.2,1,8?g/m L,RSD respectively are 7.40%,5.51%,3.63%,4.66%.1.3 RecoveryRelative recovery: at lower limit of quantification,low,medium and high concentration of 0.1,0.2,1,8?g/m L,RSD respectively are 8.86%,4.94%,2.71%,2.72%.Absolute recovery: at low,medium and high concentration of 0.2,1,8?g/m L,RSD respectively are 2.66%,1.51%,5.33%.1.4 StabilityStability after placement at room temperature for 4h: at a low,medium and high concentration of 0.2,1 and 8?g/m L,RSD respectively are 7.43%,6.90%,5.76%.Stability after twice freezethaw: at low,medium and high concentration of 0.2,1,8?g/m L,RSD respectively are 3.01%,4.45%,6.43%.Plasma sample under-70? after 14 days: at low,medium and high concentration of 0.2,1,8?g/m L,RSD respectively are 7.12%,2.04%,2.36%.Standard solution after 4 days: RSD is 7.65%.1.5 Determine the concentration of montelukast sodium after diluted 100 times,RSD is 4.03%,indicate that dilution steps has little influence on the results,which satisfied for the experimental requirements.2.Investigation on bioavailability of montelukast sodium transrectally or transnasally administratedT_max,C_max and bioavailability of montelukast sodium via rectal administration at the dose of 50mg/kg are 0.33 h,0.92mg/L,0.51%.T_max,C_max and bioavailability of montelukast sodium via nasal administration at the dose of 10mg/kg are 0.75 h,0.39mg/L,3.23%.Which demonstate that montelukast sodium itself can absorb in rectum and nasal,but has low bioavailability,rectum and nasal cavity is not the best absorption site of montelukast sodium.Both T_max of aforementioned two pathways are smaller than reported oral administration which is 3h.it indicate that montelukast sodium can be absorbed quickly in rectum and nasal cavity.3.Study on effect of different enhancers on absorption of montelukast sodium via rectal administration.At the dose of 50mg/kg,the pharmacokinetic parameters and bioavailability of montelukast sodium under various type of absorption enhancers are:3.1 With 1%sodium caprate,the Fmontelukast sodium was 3.01%,which was 5.9 times higher than that without absorption enhancer.T_1/2,T_max,C_max,AUC_0-t respectively are 2.49 h,1h,3.46mg/L,10.62mg/L*h,the promotion relating to concentration: 1%>0.5%>0.2%3.2 With 10%Tween-80,the Fmontelukast sodium was 5.28%,which was 10.4times higher than that without absorption enhancer.T_1/2,T_max,C_max,AUC_0-t respectively are 1.38 h,1h,6.18mg/h,18.62mg/L*h,the promotion relating to concentration: 10%>5%>15%.3.3 With 4%laurocapram,the Fmontelukast sodium was 2.33%,which was 4.6times higher than that without absorption enhancer.T_1/2,T_max,C_max,AUC_0-t respectively are 4.98 h,1h,2.30mg/L,8.22mg/L*h,the promotion relating to concentration: 4%>2%>10%.3.4 With 0.2%,the Fmontelukast sodium was 2.12%,which was 4.15 times higher than that without absorption enhancer.T_1/2,T_max,C_max,AUC_0-t respectively are 2.36 h,0.5h,2.30mg/L,7.48mg/L*h,the promotion relating to concentration: 0.2%>0.5%>0.1%.3.5 With 1.5%L-arginine,the Fmontelukast sodium was 2.31%,which was 4.53 times higher than that without absorption enhancer,T_1/2,T_max,C_max,AUC_0-t respectively are 4.36 h,1h,2.29mg/L,8.14mg/L*h,the promotion relating to concentration: 1.5%>1%>0.5%.3.6 With 3%sodium laurate,the Fmontelukast sodium was 1.62%,which was 3.18 times higher than that without absorption enhancer,T_1/2,T_max,C_max,AUC_0-t respectively are 2.98 h,1h,2.11mg/L,5.71mg/L*h,the promotion relating to concentration: 3%>2%>1%.3.7 With 2%chlorpromazine,the Fmontelukast sodium was 0.83%,which was 1.63 times higher than that without absorption enhancer,T_1/2,T_max,C_max,AUC_0-t respectively are 2.34 h,1h,1.51/L,3.91mg/L*h.3.8 With 1%EDTA-2NA,the Fmontelukast sodium was 0.73%,which was 1.43 times higher than that without absorption enhancer,T_1/2,T_max,C_max,AUC_0-t respectively are 2.22 h,1h,1.40/L,3.56mg/L*h.4.Study on effect of different enhancers on absorption of montelukast sodium via nasal administration.At the dose of 10mg/kg,the pharmacokinetic parameters and bioavailability of montelukast sodium under various type of absorption enhancers are:4.1 With 1%sodium caprate,the Fmontelukast sodium was 7.4%,which was 2.31 times higher than that without absorption enhancer,T_1/2,T_max,C_max,AUC_0-t respectively are 8.08 h,3h,0.60mg/L,1.39mg/L*h.4.2 With 1%sodium cholate,the Fmontelukast sodium was 4.4%,which was 1.41 times higher than that without absorption enhancer,T_1/2,T_max,C_max,AUC_0-t respectively are 1.07 h,0.5h,0.82mg/L,0.82mg/L*h.4.3 With 5%Tween-80,the Fmontelukast sodium was 5.3%,which was 1.71 times higher than that without absorption enhancer,T_1/2,T_max,C_max,AUC_0-t respectively are 3.25 h,0.75 h,0.55mg/L,1.00mg/L*h.Conclusions1.The established HPLC detection method of plasma concentration of montelukast sodium in rabbit,which linear range,precision,accuracy and stability satisfy the experimental requirements.2.Montelukast sodium can absorb in rectum and nasal cavity,while has low bioavailability,rectum and nasal cavity is not a favorable site for montelukast sodium absorption.3.Sodium caprate,Tween-80,laurocapram,sodium cholate,L-arginine,sodium laurate,chlorpromazine,all the demonstrated absorption enhancers effects on its intestinal absorption was in a concentration-dependent manner;the absorption enhancers in the order of absorption enhancing effect were 10% Tween-80>1% sodium caprate>0.2% sodium cholate>4% laurocapram>3% laurate sodium>1.5% L-arginine,and 2% chlorpromazine hydrochloride and 1%EDTA-2Na had similar effect.The effect mostly improved with the increase of concentration.The effect of the investigated absorption enhancer in increasing the transrectal bioavailability of montelukast sodium was not significantly;therefore,further investigation and screening were needed.After transrectal administration of enema containing enhancer sodium cholate,T_max was 0.5h;while T_max of montelukast sodium was all 1h with other absorption enhancers applied.Additionally,absorption rate of montelukast sodium transrectally administrated was faster as compared with oral administratio n.4.Sodium cholate,sodium caprate,Tween-80 all can promote the absorption of montelukast sodium,the absorption enhancers in the order of absorption enhancing effect were 1%sodium cholate>1%Sodium caprate>5%Tween-80.While the bioavailability was low,T_max of enema containing enhancer sodium cholate,Tween-80,sodium caprate were 0.5,0.75,3h,the absorption enhancer can promote the absorption of montelukast sodium in nasal cavity.