Masanaho Sasatsu

Preparation and biodisposition of methoxypolyethylene glycol amine–poly(dl-lactic acid) copolymer nanoparticles loaded with pyrene-ended poly(dl-lactic acid)

A formyl group-ended poly(DL-lactic acid) (PLA-aldehyde), synthesized in the same manner as reported previously, was utilized to produce the polymeric marker for PLA-related nanoparticles. Namely, pyrene-ended poly(DL-lactic acid) (PLA-pyrene) was prepared as a polymeric marker by the reductive amination of PLA-aldehyde and aminopyrene. Methoxypolyethylene glycol amine-poly(DL-lactic acid) block copolymer (PLA-(MeO-PEG) nanoparticles loaded with PLA-pyrene were prepared, and examined on retention of PLA-pyrene in the nanoparticles, and biodisposition in normal and sarcoma-180 solid tumor-bearing mice. PLA-pyrene was retained stably in PLA-(MeO-PEG) nanoparticles in a PBS-ethanol (7:3, v/v) mixture and a plasma-PBS (1:1, v/v) mixture, indicating that PLA-pyrene might be a useful marker of PLA-(MeO-PEG) nanoparticles themselves. After i.v. injection in normal rats, the plasma level of PLA-pyrene was very high for initial 8h, and accumulated gradually into organs, especially spleen and liver. After i.v. injection in tumor-bearing mice, similar biodistribution profiles of PLA-pyrene were observed, and PLA-pyrene was accumulated well in tumor, suggesting that PLA-(MeO-PEG) nanoparticles should be delivered efficiently to solid tumors. It is suggested that PLA-pyrene might be a useful probe of the nanoparticles themselves. In addition, it was demonstrated that PLA-(MeO-PEG) nanoparticles should be a useful drug carrier for passive tumor targeting.

Evaluation of matrix type mucoadhesive tablets containing indomethacin for buccal application

Nonsteroidal anti-inflammatory drugs (NSAIDs) are administered for pain relief from oral mucositis. However, the systemic administration of NSAIDs is limited due to systemic side effects. To avoid these side effects and treat local lesions effectively, a matrix type mucoadhesive tablet was developed. A mixture of hard fat, ethylcellulose (EC) and polyethylene glycol (PEG) was used as a matrix base, and indomethacin (IMC) was used as the principal agent. In tablets consisting of hard fat, EC and IMC, the drug release was sustained. In tablets consisting of hard fat, EC, considerable amounts of PEG and IMC, the drug release was relatively increased and IMC existed as the molecular phase or in an amorphous state. The in vitro adhesive force of the tablets consisting of hard fat, EC, considerable amounts of PEG and IMC was significantly increased as compared with the tablets consisting of hard fat and IMC. A significantly high tissue concentration and significantly low plasma concentration were observed after buccal administration of this matrix type mucoadhesive tablet as compared with that after oral administration of IMC. Thus, the matrix type mucoadhesive tablet has good potential as a preparation for the treatment of pain due to oral aphtha.

Kinetic analysis of in vitro and in vivo release of prednisolone from the conjugate of glycol-chitosan and succinyl-prednisolone

Recently, many people have developed rheumatoid arthritis (RA), and prednisolone (PD) is often used for treatment; however, long use and a large dose of PD can cause toxic side effects. In this study, in order to enhance the therapeutic effects and to suppress the toxic side effects, the conjugate (GC-SP) was prepared by coupling between glycol-chitosan (GC) and succinyl-prednisolone (SP). The drug-release properties of GC-SP were examined and analyzed kinetically. The plasma concentration-time profiles of GC-SP and released PD were investigated after i.v. injection to normal rats, and their pharmacokinetic profiles were analyzed. PD was stable and released gradually (ca. 1%/h) from GC-SP at physiological pH, while PD was unstable at basic pH and the release from GC-SP was accelerated at basic pH. GC-SP showed good systemic retention (more than 16-fold area under the plasma concentration-time curve (AUC) as compared to PD alone), and released PD gradually in vivo. The in vivo release rate was calculated to be much faster than the in vitro rate. From these results, it is expected that GC-SP will be accumulated at inflammatory sites based on enhanced permeability and retention (EPR) effects, and release PD there effectively.

Formulation and evaluation of matrix type mucoadhesive tablets aimed at treating oral aphtha

Context: Nonsteroidal anti-inflammatory drugs (NSAIDs) are administered for pain relief from oral mucositis. However, the systemic administration of NSAIDs is limited due to the side effects of thrombocytopenia. Objective: To avoid systemic side effects, a matrix type mucoadhesive tablet as a topical application preparation to treat oral aphtha was developed. Methods: A mixture of hard fat with a low irritant property and mucoadhesive polymers was used as the matrix base, and indomethacin was used as a model drug. Results: Among the water-soluble polymers, carbopol and xanthan gum increased the adhesive force of tablets prepared by the suspending method, but the tensile strength was not increased. Tablets containing ethylcellulose 10 or 45 (EC10, EC45) from a water-insoluble polymer increased the adhesive force and tensile strength. Tablets prepared by the dissolve-drying method containing EC45 showed a 1.8-fold increase of adhesiveness to the eggshell membrane compared with hard fat tablets, and showed a sustained release of the drug (17%) over an 8 h period. The drug release was increased to 28% by a modification to the dissolve-drying method using EC10. Conclusions: Since this matrix type tablet has long-acting properties, adhesiveness and low irritating properties, its potential as a newly designed preparation to treat oral aphtha is suggested.

Preparation and Evaluation of Stomatitis Film Using Xyloglucan Containing Loperamide

Stomatitis induced by radiation therapy or cancer chemotherapy is a factor in sleep disorders and/or eating disorders, markedly decreasing patient quality of life. In recent years, disintegrating oral films that are easy to handle have been developed; therefore, we focused on the formulation of these films. We prepared an adhesive film for the oral cavity using xyloglucan (Xylo), which is a water-soluble macromolecule. We used loperamide, which has been reported to relieve pain caused by stomatitis effectively, as a model drug in this study. Films were prepared from Xylo solutions (3% (w/w)) and hypromellose (HPMC) solutions (1% (w/w)). Xylo and HPMC solutions were mixed at ratios of 1 : 1, 2 : 1, or 3 : 1 for each film, and films 2×2 cm weighing 3 g were prepared and dried at 37°C for 24 h. Physicochemical properties such as strength, adhesiveness, disintegration behavior, and dissolution of loperamide from films were evaluated. Films prepared from Xylo solution alone had sufficient strength and mucosal adhesion. On the other hand, films prepared from a mixture of Xylo and HPMC were inferior to those made from Xylo, but showed sufficient strength and mucosal adhesion and were flexible and easy to handle. The films prepared in this study are useful as adhesion films in the oral cavity.