Pilocarpine Incorporated into a Submicron Emulsion Vehicle Causes an Unexpectedly Prolonged Ocular Hypotensive Effect in Rabbits

Naveh, Nava; Muchtar, S.; Benita, S.

doi:10.1089/jop.1994.10.509

Cited by 60 publications

(19 citation statements)

References 2 publications

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“…HU-211 in the submicron emulsion induced a short and transitory (but significant) ocular hypotensive effect in the contralateral eye, indicating that some systemic absorption had occurred. In comparison, treatment with pilocarpine in submicron emulsion exerted a pronounced significant contralateral reduction in IOP [30], indicative of prolonged systemic absorption.…”

Section: Discussionmentioning

confidence: 91%

“…Maximal IOP reduction was 5.3 mmHg (24% of baseline level) at 1.5 h post single dose instillation. IOP reduction effect persisted for more than 6 h. In comparison, pilocarpine dissolved in the same vehicle acted for a longer period of time, with maximal IOP reduction of 6.0 mmHg (28.5% of baseline level) [30]. HU-211 in the submicron emulsion induced a short and transitory (but significant) ocular hypotensive effect in the contralateral eye, indicating that some systemic absorption had occurred.…”

Section: Discussionmentioning

confidence: 93%

“…HU-211, to be useful as a potential drug in glaucoma therapy, requires a suitable vehicle. In the present study, an emulsion previously developed by us for the incorporation of pilocarpine into ophthalmic preparation [30] of eye drops was tested as a vehicle for HU-211.…”

Section: Discussionmentioning

confidence: 99%

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A submicron emulsion of HU-211, a synthetic cannabinoid, reduces intraocular pressure in rabbits

Naveh

Weissman

Muchtar

et al. 2000

Graefe's Archive for Clinical and Experimental Ophthalmology

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Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 93%

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A submicron emulsion of HU-211, a synthetic cannabinoid, reduces intraocular pressure in rabbits

Naveh

Weissman

Muchtar

et al. 2000

Graefe's Archive for Clinical and Experimental Ophthalmology

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“…22 Lipid emulsions are exploited commercially as a vehicle to improve the ocular bioavailability of lipophilic drugs. 23,24 Naveh et al 25 noted that the intraocular pressure-reducing effect of a topically administered dose of pilocarpine-loaded lipid emulsions is prolonged compared with that of generic pilocarpine. Calvo et al 26 observed an improvement in indomethacin ocular bioavailability when the drug is incorporated in a lipid emulsion compared with commercial aqueous drops after topical application into the rabbit eye.…”

Section: Discussionmentioning

confidence: 99%

Physicochemical Properties Affecting Retinal Drug/Coumarin-6 Delivery from Nanocarrier Systems via Eyedrop Administration

Inokuchi¹,

Hironaka

Fujisawa

et al. 2010

Invest. Ophthalmol. Vis. Sci.

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PURPOSE.To elucidate the effect of physicochemical properties of nanocarrier systems on drug delivery efficiency to the retina by eyedrop administration in mice, rabbits, and monkeys. METHODS. Submicron-sized liposomes (ssLips) of different particle size, cholesterol content, surface charge, and multilamellar vesicles (MLV) were prepared by the hydration method. Fluorescence probe (coumarin-6)-incorporated liposomes, lipid emulsions, and FITC-labeled polystyrene particles were used to investigate their intraocular behavior after eyedrop administration, using epifluorescence microscopy in mice, rabbits, and monkeys. RESULTS. Delivery efficiency of fluorescent probes to the mouse retina from dropped liposomes was extensively improved by reducing their particle size (Ͻ600 nm) and cholesterol content, whereas negligible improvement was observed in the case of MLV. Furthermore, FITC-labeled polystyrene particles and coumarin-6 -incorporated lipid emulsions showed an insufficient effect on retinal delivery in mice even if their size was controlled at 110 nm. The highest accumulation of the fluorescent probe in the retina was observed around 30 minutes with any type of ssLip used, followed by the prompt disappearance of their fluorescence within 120 minutes in mice. Changes in the fluorescence intensity of coumarin-6 in rabbits and monkeys were observed in a manner similar to that described in mice. Retinal flat-mount images suggest that coumarin-6 incorporated in ssLip diffused from the iris and ciliary body side to the optic disc side in the retina after eyedrop administration. CONCLUSIONS. The delivery efficiency of coumarin-6 to the retina was altered depending on particle size, constituents, and rigidity. ssLips with appropriate features would be promising drug carriers for retinal delivery through eyedrops. (Invest Ophthalmol Vis Sci.

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“…Em um estudo aleatório, do tipo duplo-cego, realizado por Naveh et al, a pilocarpina incorporada em uma microemulsão preparada com um emulsionante anfotérico (Miranol  MHT) e fosfolípides de gema de ovo (Lipoid  E-80), foi aplicada, em dose única, a coelhos com pressão normal, produzindo uma diminuição progressiva e prolongada da pressão ocular (16) . O efeito foi mais prolongado e intenso que o induzido pela dose correspondente do colírio padrão de cloridrato de pilocarpina.…”

Section: Potencialidades Que Justificam a Administração Oftálmicaunclassified

Microemulsões como veículo de drogas para administração ocular tópica

Silva-Cunha¹,

Fialho²,

Carneiro³

et al. 2003

Arq. Bras. Oftalmol.

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As formas farmacêuticas oftálmicas convencionais são relativamente simples: drogas solúveis em água são formuladas em solução aquosa e drogas pouco solúveis em suspensão ou pomada. Entretanto, essas formulações apresentam como inconvenientes baixa biodisponibilidade corneal, absorção sistêmica devida à drenagem nasolacrimal e reduzida eficácia no segmento posterior do olho. Assim, o desenvolvimento de novos sistemas de liberação de drogas de administração oftálmica tem sido um dos principais temas de pesquisa em tecnologia farmacêutica nos últimos anos. Entre as alternativas avaliadas, destacam-se principalmente as microemulsões. Estas formas farmacêuticas que são dispersões de água e óleo, estabilizadas por um emulsionante e por um co-emulsionante, transparentes, termodinamicamente estáveis, apresentam partículas de tamanho menor que 1,0 µm e, portanto, passíveis de serem esterilizadas por filtração. Além disso, as microemulsões apresentam baixa viscosidade, possuem grande capacidade para o transporte de drogas, demonstram comprovada propriedade promotora de absorção para as drogas veiculadas e são facilmente obtidas, sem a necessidade de utilização de equipamentos sofisticados e de componentes de custo proibitivo. O presente artigo objetiva revisão de literatura abordando o tema e os principais estudos relacionados com a utilização de microemulsões como sistemas de liberação de drogas oftálmicas. I N T R O D U Ç Ã OA administração tópica de drogas na forma de soluções, suspensões, géis e pomadas é o método mais comum de tratamento de doenças oculares. Entretanto, essa via apresenta alguns problemas como baixa biodisponibilidade, perda da droga pela circulação sistêmica e a baixa, ou praticamente inexistente, penetração da formulação no segmento posterior do olho.A baixa biodisponibilidade ocular é resultante de barreiras anatômicas e fisiológicas do olho, que incluem o epitélio corneal, a dinâmica das lágri-mas, a drenagem nasolacrimal e alta eficiência da barreira ocular sangüínea. Geralmente, apenas 5% da dose administrada atinge os tecidos intra-oculares através da penetração corneal, enquanto que a grande parte é absorvida sistemicamente pela conjuntiva e duto nasolacrimal podendo causar reações adversas em diversas partes do organismo. Para se atingir o nível terapêu-tico adequado, são necessárias elevadas concentrações e/ou freqüentes administrações, o que pode aumentar o risco de efeitos adversos sistêmicos e interações medicamentosas.

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Pilocarpine Incorporated into a Submicron Emulsion Vehicle Causes an Unexpectedly Prolonged Ocular Hypotensive Effect in Rabbits

Cited by 60 publications

References 2 publications

A submicron emulsion of HU-211, a synthetic cannabinoid, reduces intraocular pressure in rabbits

A submicron emulsion of HU-211, a synthetic cannabinoid, reduces intraocular pressure in rabbits

Physicochemical Properties Affecting Retinal Drug/Coumarin-6 Delivery from Nanocarrier Systems via Eyedrop Administration

Microemulsões como veículo de drogas para administração ocular tópica

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