Multi-phase compositions for an initial and delayed release of a

Details Multi-phase compositions for an initial and delayed release of a Multi-phase compositions for an initial and delayed release of a

1996-06-24

1999-11-16

Moezie, Minna

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Liposomes

514398, 514967, A61K 9127, A61K 31415

Patent

active

059853190

DESCRIPTION:

BRIEF SUMMARY
This invention concerns novel pharmaceutical compositions for combating vaginal infections.
It is desirable for a pessary to be able to treat all the common forms of vaginitis, which are most often caused by infection with Candida albicans, Trichomonas vaginalis or Gardnerella sp, either singly or mixed. Commonly derivatives of imidazole and nitroimidazole are used to treat such conditions, examples of such drugs being miconazole, clotrimazole, ornidazole, tinidazole and metronidazole, but despite the good activity of these compounds none has so far individually achieved the broad spectrum of activity required to combat all the common types of infection. Other types of drugs used in such infections include nitrofurfuryl derivatives and various antibiotics.
While such drugs have been formulated as pessaries and vaginal tablets, it has been found for metronidazole that the relapse rate with trichomonal infections (i.e. the rate of reappearance of infection after cessation of the medicament) is higher when administered in this way than when administration is by the oral route. Consequently the oral route is now the preferred route for administration of metronidazole, and pessaries containing this compound have been virtually discontinued. This results in mixed vaginal infections being treated by both the oral and vaginal routes, with consequent inconvenience to the patient.
However, the half life of most anti-vaginitis medicaments is generally relatively short, for example six hours, and it is difficult to formulate a medicament which can effectively be administered only once a day. On the other hand, when starting administration, it is preferable to provide a relatively large booster dose of the active substance, so that a delayed release formulation is not entirely satisfactory. Similarly, even when using delayed release, levels of the active substance tend to fall towards the end of the period, for example 24 hours, so that a booster dose may be desirable at intervals during medication.
We have found that it is possible to reconcile the above requirements by providing multiphase formulations comprising a continuous phase containing a relatively large amount of one or more anti-vaginitis medicaments for relatively rapid initial release and containing, dispersed therein, microporous particles containing one or more of the anti-vaginitis medicaments and releasing these over a prolonged period, for example 24 hours.
According to the present invention we provide a pharmaceutical composition for the treatment of vaginitis comprising a continuous phase containing one or more anti-vaginitis medicaments for rapid release and porous particles dispersed therein adapted for delayed release of one or more anti-vaginitis medicaments.
In one embodiment of the invention we provide a cream containing the anti-vaginitis medicament(s) together with porous particles containing one or more of anti-vaginitis medicaments.
The phase in which the medicament(s) are contained may be a conventional cream base, e.g. containing oily or waxy materials such as liquid paraffin, white petroleum or cetyl alcohol, water and one or more surfactants to produce a water-in-oil emulsion. A bactericide such as benzalkonium chloride is conveniently present.
According to a further embodiment of the invention, the compositions take the form of pessaries comprising a pessary base containing the anti-vaginitis medicament(s) and porous particles for delayed release of anti-vaginitis medicament(s).
The pessary base may be of any conventional material for vaginal administration such as glycerol/gelatin glyco-gelatin, macrogols (polyethylene glycols), natural, synthetic or semisynthetic hard fats, and fractionated palm kernel oil. A particularly preferred material is a hard fat such as cocoa butter (theobroma oil), for instance the range of cocoa butter-based products sold under the trade name Witepsol by Dynamit Nobel, Slough, England.
The pessary base may conveniently contain a surfactant to promote dispersal of the active substances. It may also be adva

REFERENCES:
patent: 4690825 (1987-09-01), Won
patent: 4713247 (1987-12-01), Sakamoto et al.
patent: 4873091 (1989-10-01), Jankower et al.
patent: 5045082 (1991-09-01), Ayer et al.

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