ABSTRACT
For many decades, radiotherapy with its different modalities has proved to be the gold standard in the treatment of benign and malignant intraocular tumours. The various complicated therapeutic developments in this field cover a period of over 100 years and the present year deserves special mention because of the 100th anniversary of the first mention of a successful brachytherapy for a uveal melanoma by R. Deutschmann in Hamburg in 1915.
Subject(s)
Brachytherapy/methods , Eye Neoplasms/diagnosis , Eye Neoplasms/radiotherapy , Radiotherapy, Conformal/methods , Evidence-Based Medicine , Humans , Treatment OutcomeABSTRACT
There are multiple possible intraocular manifestations in patients with systemic neoplasms. At first line there are uveal, retinal and vitreous metastases from carcinomas, melanomas and lymphomas. In patients with von Hippel Lindau syndrome or familiar adenomatous polyposis coli (FAP), Gardner or Turcot syndromes, fundus examinations can help in the primary diagnosis and thereby facilitate the early detection of systemic neoplasms such as cerebral and spinal haemangioblastoma, kidney or bowel cancer. Furthermore there are rare ocular paraneoplastic syndromes such as the cancer- or melanoma-associated retinopathies (CAR/MAR), the paraneoplastic optic neuropathy (PON) and the bilateral diffuse melanocytic proliferation (BDUMP) that develop secondary to systemic malignancies and can be the primary manifestation.
Subject(s)
Eye Diseases/diagnosis , Eye Diseases/etiology , Neoplasms/complications , Neoplasms/diagnosis , Paraneoplastic Syndromes/complications , Paraneoplastic Syndromes/diagnosis , Diagnosis, Differential , HumansABSTRACT
PURPOSE: To develop scleral controlled-release-systems of triamcinolone acetonide (TA) based on biodegradable poly(lactide) (PLA). MATERIALS AND METHODS: (1) PLA microspheres containing TA were prepared by a single or double emulsification-solvent evaporation method. Morphology, size, effect of drug input and method of microsphere preparation on drug loading, and in vitro TA release of the microspheres were investigated. (2) Mini-tablets consisting of blank PLA-microspheres and TA (weight ratios of 1:1, 2:1, and 4:1, respectively) were developed and their release profile in vitro was evaluated. (3) The in vitro transscleral diffusion profile was evaluated by placing a PLA-TA (1:1) tablet in a donor chamber and measuring the TA concentration in a receptor chamber. Donor and receptor chambers were separated by rabbit sclera. (4) Two cadaver rabbit eyes received a 1:1 PLA-TA tablet episclerally, which was covered by a scleral patch. TA aqueous humor and vitreous concentrations were measured 5, 10, and 20 days post implantation. RESULTS: (1) Microsphere average size was 2 µm. The double emulsification method and increasing drug input led to an increase in drug loading and encapsulation. Sustained release of TA over several days from the microspheres in vitro was observed, with the rate of release being affected by their TA content. (2) TA exhibited sustained release profile from the PLA-TA tablets, with the rate of release being affected by the PLA:TA ratio. (3) TA could slowly cross the sclera tissue in vitro, with approximately 21% of the drug loaded in the donor compartment being diffused through the sclera in 45 days. (4) Following scleral administration of the PLA-TA mini-tablets, TA accumulated in the vitreous and aqueous humor of cadaver eyes. CONCLUSIONS: The PLA-TA microspheres and mini-tablets appear promising for the controlled transscleral delivery of TA and justify further investigation.
