Abstract
to determine the functional and morphological effects at rabbits retina of PS80 concentration used in the preparation of intravitreal drugs. eleven New Zealand rabbits received a intravitreal injection of 0.1ml of PS80. As control, the contralateral eye of each rabbit received the same volume of saline. Electroretinography was performed according to a modified protocol, as well as biomicroscopy and retina mapping before injection and seven and ten days after. Animals were euthanized in the 30th day and the retinas were analyzed by light microscopy. eyes injected with PS80 did not present clinical signs of intraocular inflammation. Electroretinography did not show any alteration of extent and implicit time of a and b waves at scotopic and photopic conditions. There were no morphological alterations of retinas at light microscopy. intravitreal injection of PS80 in the used concentration for intravitreal drug preparations do not cause any functional or morphological alterations of rabbit retinas. These results suggest that PS80 is not toxic to rabbit retinas and may be safely used in the preparation of new lipophilic drugs for intravitreal injection.
Highlights
IntroductionDrug access to the retina and choroid has always been a challenge to ophthalmologists due to the existence of two anatomic barriers (internal and external blood-retinal barriers) that impairs penetration of drugs in the posterior segment of ocular bulbus
Drug access to the retina and choroid has always been a challenge to ophthalmologists due to the existence of two anatomic barriers that impairs penetration of drugs in the posterior segment of ocular bulbus
Obtained results suggest that PS80 concentration used in this study (the same used in preparation of drugs for intravitreal use to treat retina diseases (0.4% w/v) is not toxic to rabbit retinas
Summary
Drug access to the retina and choroid has always been a challenge to ophthalmologists due to the existence of two anatomic barriers (internal and external blood-retinal barriers) that impairs penetration of drugs in the posterior segment of ocular bulbus. Treatment of blindness secondary to most prevalent retina and choroid diseases (macular degeneration related to age and diabetic retinopathy) has changed dramatically with the use of intravitreal injection of therapeutic agents in the posterior segment of ocular bulbus[1]. Intravitreal injection of drugs overcomes external blood-retinal barrier and assures that retina and choroid receive therapeutic level of drugs, lowering significantly systemic absorption and consequent toxicity. According to Brazilian and World legislation, intravitreal injection of drugs is a surgical procedure and must be performed under rigorous aseptic technique. Some pharmacological aspects must be considered, such as the aqueous solubility, pharmacokinetics and biochemical proprieties of the compounds, as well as their interaction with the vitreous[2]
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