Purchase this article with an account.
R. Suverkrup, K. Gruner, M. Diestelhorst; Spherolyophilizates as Ophthalmic Drug Delivery Systems. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5557.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
It has been shown that carrier-based lyophilizates are preservative free, chemically stable and physiologically inert delivery systems with superior topical bioavailability (1). The adhesive force between the formulation and the carrier membrane is a critical quality parameter, which is not always easy to control, particularly for extended time periods, and some individuals found it difficult to separate the dried droplet by wiping it over the lower palpebra. Therefore, lyophilizates in the form of free-flowing and readily aerosolizable powders with porous spherical particles of uniform size and low density have been developed as an alternative dosage form, which shares the advantages of OLCS but eliminates potential shortcomings.
A jet of uniform droplets of aqueous latanoprost or fluorescein solutions containing carbohydrate bulking excipients is generated by a piezoelectric dispenser head and frozen immediately by injection into a cold dry gas stream. The spherical ice particles are collected and freeze-dried to a residual water content below 5 % in a laboratory lyophilizer. The product is a free-flowing powder, which is readily dispersed in a current of air. Size, appearance and internal structure of the particles were characterized by scanning electron microscopy, atmospheric water uptake by dynamic vapor sorption. Bulk density, flow and aerodynamic behaviour were determined by suitable micromethods. The dose uniformity is being studied gravimetrically.
Production methods have been optimized for particles with mean diameters of 200 µm. Doses of approximately 1.5 mg drug-free mannitol spherolyophilizates blown onto the cornea are well tolerated.
Spherolyophilizates share the advantages of carrier based ophthtalmic lyophilizates but are easier to administer from blister packs similar to powder aerosol units. A continuous aseptic production method in a closed system is under development.(1) Steinfeld A, Lux A, Maier S, Süverkrüp R, Diestelhorst M: Bioavailability of Fluorescein from a new drug delivery system, Br. J. Ophthalmol. 2004, 88:48-53
This PDF is available to Subscribers Only