Formulation And Evaluation Of Orodispersible Films Containing Cucurbitacin B Loaded Phospholipid-bile Salts-mixed Micelles

The application of many drugs used today is limited due to poor oralbioavailability caused by poor water solubility. phospholipid/bile salt mixed micelles（PL/BS-MMs), as novel nano drug delivery system, was an effective approach forimproving water solubility and bioavailability of drugs with poor water solubility. Butthere are many limitations associated with liquid formulations. Storage and shippingof the drug loaded PL/BS-MMs maybe not convenient to take and carry. All of theseproblems seriously restricted the application and promotion of PL/BS-MMs.Orodispersible films (ODFs), a relatively new solid dosage form with rapid release fororal administration, are gaining more interest because of many advantages such asease of administration, rapid release etc. However, ODFs are not suitable for thedelivery of drugs with poor water solubility because the drugs with poor watersolubility have low bioavailability due to poorly oral absorption.In order to enhance water solubility and bioavailability of active ingredient withpoor water solubility and improve the stability of PL/BS-MMs, a novel ODFscontaining PL/BS-MMs （PL/BS-MMs-ODFs） was developed by combining theadvantages of PL/BS-MMs and ODFs with aim of transforming drug loadedPL/BS-MMs into a solid dosage form as well as overcoming the problem that ODFsare not suitable for the delivery of drugs with poor water solubility in this paper.Cucurbitacin B (Cu B) was chosen as a model drug and studied systematically.The HPLC method was developed for the determination of Cu B．The results ofcompatibility study between Cu B and other excipients showed that PL, SDC,pullulan, PEG400, L-HPC and aspartame can be used to study the preparation of CuB. Determination of the solubility of Cu B in the vehicle showed the stronghydrophobicity of Cu B.Cu B-PL/BS-MMs was prepared by a film dispersion method. To prepare theMMs and to serve as the micellular carrier, a weight ratio, the total concentration ofPL and SDC, and the concentration of Cu B were selected based on the size, size distribution, zeta potential, encapsulation efficiency and morphology. The bestpreparation process was determined as follows:3g PL was dissolved by anhydrousethanol in a round-bottom flask. A thin film was formed after evaporation of organicsolvent by rotary evaporator.2.4g SDC was dissolved by100mL distilled water. Thelipid film was mixed with the SDC solution in a water bath at45℃, then the clearblank PL/BS-MMs was obtained.0.5g Cu B was added to the blank PL/BS-MMs,nitrogen sealed, mixed24h on a magnetic stirre at room temperature to form CuB-PL/BS-MMs. Results showed that a narrow size distributed (PI=0.146±0.004)nanomicelles with a mean particle size of (86.21±6.11) nm and a zeta potential of(-31.21±1.17) mV was obtained in our optimized Cu B-PL/SDC-MMs formulation.The encapsulation efficiency under such conditions could be up to97.68%. The TEMstudy of Cu B-PL/BS-MMs showed that the Cu B-PL/SDC-MMs were spherical inshape with particle sizes around100nm which was consistent with the resultsobtained by zeta sizer. The optimized Cu B-PL/SDC-MMs was a stable colloidalsystem in72h with the constant particle size and EE. The fluorescent probe methodcombining with Origin software fitting curve were used for the determination of CMCof Cu B-PL/SDC-MMs, the results showed CMC was0.047g/L, which indicatinggood anti-dilutive effect when mixed micelles go into the systemic circulation.In order to improve the stability of Cu B-PL/SDC-MMs, a novel CuB-PL/BS-MMs-ODFs was prepared by solvent casting, combining the advantages ofPL/BS-MMs and ODFs. The formulations of Cu B-PL/BS-MMs-ODFs wereoptimized by employing the Box–Behnken design-response surface methodology. Theoptimized formulation process of HPE-NS-ODFs was as follows: pullulan（53mg/mL） and PEG400（40mg/mL） were dissolved in10ml Cu B-PL/SDC-MMssolution containing50mg Cu B and mixed so as to get a homogeneous solution.Sweeteners like aspartame were also mixed with the above solution. The solution wasallowed to stand for45min to allow deaeration to take place. Then it was casted on apetridish and dried at room temperature for24hour. The resultant film was cut intothe quadrate of2cm×2cm in size and packaged. The SEM study of CuB-PL/BS-MMs-ODFs showed that the pullulan network formed a dense continuoussheet with no fractures and the films exhibited an unequivocally uniform distributionof nanoparticles in both peripheral and middle portions. Values of elastic modulus,tensile strength and elongation at break were within the acceptable range. The disintegration test displayed that Cu B-PL/BS-MMs-ODFs could disintegratecompletely within31s. The FDOFs containing Cu B-PL/SDC-MMs was easilyreconstituted in a transparent and clear solution giving back a colloidal system withspherical micelles in the submicron range. All of these results suggest that the FDOFscontaining Cu B-PL/SDC-MMs have been successfully prepared.To explore the oral absorption kinetics of Cu B-PL/BS-MMs-ODFs, the in situintestine single-pass perfusion experiments were performed. The results demonstratedthat, the dissolution rate of Cu B-PL/BS-MMs-ODFs had obvious advantagescompared to Cu B-PM and Cu B-Bulk. The absorption rate constant (Ka) of CuB-PL/BS-MMs-ODFs was improved by3.57times and4.27times compared to theCu B-PM and Cu B-Bulk respectively, the absorption half-life (t1/2) is also reduced.The results showed that, to prepare Cu B to PL/BS-MMs-ODFs can significantlyimprove the in vivo absorption of the drug (p <0.05).This pharmacokinetics of Cu B-PL/BS-MMs-ODFs in rats was studied in thispaper. The results showed that compared to the Cu B suspension, the Tmaxfrom CuB-PL/BS-MMs and Cu B-PL/BS-MMs-ODFs were lower significantly (p <0.05) andthe AUC0-24hfrom MMs and Cu B-PL/BS-MMs-ODFs resulted in2.47-fold and2.63-fold increased as compared to Cu B suspension, respectively (p <0.05). Nosignificant difference was observed between the Cu B-PL/SDC-MMs and CuB-PL/BS-MMs-ODFs for pharmacokinetic parameters.The HPLC method was developed for the determination of Cu B in ratsbiological samples. The results showed that to prepare Cu B to PL/BS-MMs-ODFscan significantly improve the liver and spleen targeting.In order to know the cytotoxicity of Cu B-PL/BS-MMs-ODFs, HepG-2cellswere exposed to various dilutions of equivalent concentrations of free Cu B or CuB-PL/BS-MMs-ODFs, and the percentage of viable cells was quantified with an MTTassay. The results demonstrated that, the antitumor effect induced by HepG-2cells ofCu B suspension and Cu B-PL/BS-MMs-ODFs have the dose-and time-dependentmanner, and the antitumor effect of Cu B-PL/BS-MMs-ODFs was significantly higherthan that of Cu B suspension.In summary, PL/BS-MMs-ODFs could significantly improve the bioavailabilityof Cu B, enhance the liver and spleen targeting, and make the higher antitumor effect.Therefore, the combination of PL/BS-MMs and ODFs that applied to delivery poorly soluble active ingredients is an effective method for enhancing water solubility andbioavailability of poorly soluble active ingredients as well as providing a simple andcost-effective manner for the solidification of PL/SDC-MMs.