Research On The Inclusion Complex Of Nebivolol Hydrochloride-HP-?-CD And Buccal Adhesive Tablets

Objective:Nebivolol hydrochloride was the new third generation of ?-blockers,which was developed by Johnson and Johnsoncompany.Nebivolol was uesd for the treatment of mild-to-moderate hypertension,chronic cardiac failure and angina.Nebivololcan dilate blood vessels though adjusting the arginine-NO channel.So far,only Nebivolol tablets have been available on the market.When taken orally,part of patients have low bioavailability.For patients with rapid metabolism,the bioavailability was only 12%,that might be associated with its poor solubility in water and liver first-pass effect.In this study,cyclodextrin inclusion technique was usedto enhance the solubility in water and thus to increase the bioavailability of NBH.In addition,a new buccal delivery sustained release preparation : bioadhesive double-layer tablet,was prepared,which could not only avoid the liver first-pass effect,prolong the residence time in oral mucosa,but also improve the bioavailabilityand reduce the individual difference.Methods:(1)The preformulation research of Nebivolol hydrochloride:The concentration of Nebivolol hydrochloride was determined by HPLC,saturated solution and shake flask method was applied to determine the equilibrium solubility and the apparent oil/water partition coefficient of nebivolol hydrochloride in water?0.1mol·L-1 Hcl and phosphate buffer solution with different pH(pH2.0?pH6.8?pH7.4?pH8.0).The test of API influencing factors examined the hygroscopicity and stability of Nebivolol hydrochloride under the conditions of high temperature,high humidity,and strong light.(2)The preparation and characterization of HP-?-CD Nebivolol hydrochloride inclusion complexes:The inclusion compound was prepared by solution-mixing and freeze-drying method;The inclusion technology was optimized by L9(34)orthogonal design with mole ratio of Nebivolol hydrochloride-HP-?-CD,inclusion temperature,inclusion time and Ethanol concentration as factors using inclusion rate as index;The validation test was conducted by phase solubility method,Infrared spectrophotometry(IR),X-ray diffraction(XRD)and Nuclear Magenetic Resonance(NMR).The entrapment efficiency and drug-loaded amount were determined by the method of HPLC.Lastly,saturated solution method was applied to determine the equilibrium solubility of NBH and inclusion complexes separately,so as to investigate the solubilization.(3)The preparation of the inclusion complex bioadhesive double-layer tablets :The double-layer tablets were prepared by direct compression method.In order to reduce patients' discomforts,this study intended to prepare the bioadhesive tablets with 6 mm in diameter,weighing about 60 mg.At the begining,single factor tests were carried out to inspect the varieties,amount and proportion of adhesive materials for inside-layer tablet,each formulation was evaluated using the adhesiveforce and in vitro release.According to the results of single factor tests,the varieties of adhesive materials were determined.And then,a further Central-Composite design of 2 factors at 5 levels was adopted for optimizing the varieties and amount of adhesive materials.(4)The evaluation of inclusion complextablet :To develop a HPLC method for determination of NBH,and then validation methods were performed.The pharmaceutical characterizationswere detected,according to the Chinese Pharmacopoeia,2015Vol-ume.The force of the lever balance principle was applied to test the adhesive force with self-prepared device;The release in vitro was determined by UV spectrophotometry,and the release curve was fitted by the zero-order ? first-order ? Higuich and Ritger-Peppas equation separately.Results:(1)At 37±0.5?,the equilibrium solubility of nebivolol hydrochloride in water and in 0.1 mol·L-1 Hcl was 722.53?g·ml-1and 56.07?g·mL-1 respectively;the apparent oil/water partition coefficient of nebivolol hydrochloride was 1.17 and 1.32.In the pH range of 2.0~7.4,With the aggrandizing of p H value,the equilibrium solubility and the oil/water apparent partition coefficient increased and decreased with pH values respectively;while pH increased from 7.4 to 8.0,the equilibrium solubility of Nebivolol hydrochloride increased and Log P decreased.The average weight gain rate of nebivolol hydrochloride was 2.67%;according to the moisture absorption characteristics and definition of gaining weight,nebivolol hydrochloride belongs to be hygroscopic.The results of influencing factors indicated that nebivolol hydrochloride was stable under the condition of high temperature,the drug content decreased and the related substances had no evident change under the conditions of high humidity and strong light.The raw material and preparations of nebivolol hydrochloride were advised to keep in cool and dark places away from moisture,so as to guarantee the drug to reach the “safe,stable,effective” quality requirements.(2)Theoptimum inclusion process was as follows:Nebivolol hydrochloride-HP-?-CD(mole ratio=1:1),the inclusion temperature was 40?,inclusion time was 4h and Ethanol concentration was 80%;The validation demonstrated an obvious difference between the inclusion complexes and physical mixture,and the phase solubility curve indicates AL type.The inclusion complexes' entrapment efficiency was(73.69±0.10)%,and the drug-loaded amount was(16.70±0.22)%,whose results of measurement are in agreement with its theory.The solubility of Nebivolol hydrochloride in the inclusion complex was 3.18 and 11.10 times higher than that of pure Nebivolol hydrochloride in purified water and pH 6.8 phosphate buffer.(3)Simple factor analysis shows,CP and HPMC were together selected as the oral mucoadhesive material.Using the total amount and the proportion of CP and HPMC as factor A and B separately.The range of selective value of factor A was 5%~25% and and factor B was 0.2:1~1:1.The ultimate prescription was as follows:the inside-layer contained the inclusion complex that made up 11% of all prescriptions(equivalent to nebivolol hydrochloride 5 mg);CP 71 G NF and HPMC were ueded 11.45% of the total,respectively regarded as adhesive materials and sustained-releasematrix material with the percentage of 0.32:1;37.15% mannitol was included as fillers;magnesium stearate and colloidal silicon dioxide respectively accounted for 0.8% and 0.6%.The side of tablet was coated with 10% EC ethanol solution as protective layer,and let it dry naturally.(4)The results of the pharmacy evaluation are as follows:The inner layer of this preparation is white or off-white,and the outer layer was covered with 10% EC ethanol solution?The result of content uniformity was shown,A+1.80S<15.0,and its result conformed to the standard of Chinese Pharmacopeias.The adhesive force of three batches of samples also conformed to the regulation of oral adhesion preparation.During 8h,drug release curve was fit with Ritger-Peppas equation:LnQ=0.5649lnt-1.3442,R2=0.9776,which indicated that NBH release followed non-fick diffusion mechanism.The results of method evaluation showed that this method was sample and fast with good specificity,linearity,accuracy,repeatability and high recovery.Conclusion:This method of solution agitation-freeze drying was applied to prepare the inclusion compound,and the craft is advanced,reasonable,which not only solved the poor water-solubility of NBH,but also producted the loose solid powder.The inclusion compound was used as the tabletting main drug,and CP and HPMC were bioadhesive materials.The oral mucosal double-layer tablet were prepared by direct compression method.The preparation process was simple and feasible,and could meet the requirements of one-way release.The drug was absorbed by the oral mucosa,which can not only avoid the influence of enzyme and acid liquid in gastrointestinal and hepatic first pass effect,but also can improve the bioavailability.It can provide a useful reference for further research and development for new formulations of NBH.The methodological evaluation showed that the HPLC method has the advantages of high recovery rate,strong specificity,linearity,precision and repeatability.The quality evaluation showed that the main indexes of the preparation conformed to the Pharmacopoeia regulation.The results of in vitro experiments showed,the determination methods of release and adhesive force were scientific and simple,and the adhesion force was ideal and the release rate was suitable.It was in line with the relevant regulations of oral adhesive preparations.