1. Field of the Invention
The present invention relates to a powdery pharmaceutical composition suitable for application to the mucosa of the oral or nasal cavity. More specifically, it relates to a powdery pharmaceutical composition, suitable for application to the mucosa of the oral or nasal cavity, containing (a) lower alkyl ethers of cellulose as a base, (b) a steroid or glycyrrhizic acid type anti-inflammatory agent as a drug component, and (c) a solid low irritant organic acid as a stabilizer for the drug component.
The powdery pharmaceutical composition exhibits extremely excellent stability in the steroid or glycyrrhizic acid type anti-inflammatory agent contained therein, low irritation of the mucosa of the oral or nasal cavity, and sustained release of the drug over an extended period of time. Accordingly, the powdery pharmaceutical composition according to the present invention can be effectively used for the treatment of oral diseases such as stomatitis, erosion or sores generated by radiotherapy, and licken planus or nasal diseases such as allergic rhinitis and vasomotor rhinitis.
2. Description of the Related Art
Various pharmaceutical preparations, such as buccal tablets, troche tablets, sublingual tablets, and oral ointments, have been heretofore known in the art for application to the oral cavity. Buccal tablets, troche tablets, and sublingual tablets, however, give a foreign feeling to the oral cavity. Therefore, patients often chew on and swallow the tablets. Oral ointments, on the other hand, usually contain mixtures of beeswax or plastibase with gelatin, pectin, or sodium carboxymethyl cellulose. These mixtures are unsatisfactory because the adhesion properties thereof to the oral mucosa are not sufficient and also because they have unpleasant tastes.
On the other hand, various pharmaceutical preparations, such as nasal ointments, jellies, nose drops, and sprays, have been known in the art for application to the nasal cavity. Nasal ointments and jellies, however, are difficult to apply to deep parts of the nasal cavity, such as the concha nasalis superior. With, nose drops and sprays, the active components do not remain in the nasal cavity for an extended period of time.
Various sustained release pharmaceutical preparations for oral or nasal cavity administration are known in the art. With these, the efficacy of the drugs is spread over a long period of time by the gradual or sustained releasing the active drug components from the pharmaceutical preparations. For example, Japanese Unexamined Patent Publication (Kokai) No. 57-118511 discloses powdery sustained release preparations suitable for adhesion to the oral cavity. These preparations use, as a base, hydroxypropyl cellulose and have the advantages of an excellent sustained release of the drugs and possible application over a wide range of the oral cavity. Furthermore, U.S. Pat. No. 4,294,829 discloses powdery sustained release preparations suitable for application to the nasal cavity. These contain lower alkyl ethers of cellulose and drugs and also have the advantage of excellent sustained release of the drugs.
It is, however, more desirable to improve the stability of drugs in the above-mentioned sustained release preparations for application to the mucosa of the oral or nasal cavity.