Vehicle Effects on Ocular Drug Bioavailability II: Evaluation of Pilocarpine

Sieg, James W.; Robinson, Joseph R.

doi:10.1002/jps.2600660905

Cited by 111 publications

(26 citation statements)

References 28 publications

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“…The turnover rates in rabbits and humans are on average very much the same, therefore. Considerably larger values are found in the stimulated eye (SIEG and ROBINSON 1977) or on deviations from physiological pH (CONRAD et al 1978), but the flow returns to baseline after topical anesthesia (PATTON and ROBINSON 1975). The position of the animal's head, when it is under anesthesia, has a noticeable effect on drainage (SIEG and ROBINSON 1974).…”

Section: A} Tearsmentioning

confidence: 93%

“…This conclusion would also apply to results with chloramphenicol (HONEGGER 1961), which penetrated to the same extent whether given as a crystalline suspension in grease or dissolved in grease by means of an emulsifier. SIEG and ROBINSON (1977) also studied pilocarpine as a water-in-oil emulsion, in which the drug is dissolved in the aqueous phase. Penetration of the cornea was the same whether its epithelium was intact or abraded, and it was concluded that availability of the drug was limited by the area of free surface between the ointment and the tear film.…”

Section: B) Contact With Ocular Surfacementioning

confidence: 99%

See 1 more Smart Citation

Ocular Pharmacokinetics

Maurice¹,

Mishima²

1984

Handbook of Experimental Pharmacology

224

169

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Section: A} Tearsmentioning

confidence: 93%

Section: B) Contact With Ocular Surfacementioning

confidence: 99%

Ocular Pharmacokinetics

Maurice¹,

Mishima²

1984

Handbook of Experimental Pharmacology

224

169

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“…Main reasons for law bioavailability of drugs from orthodox formulations are quick drainage of drugs from the precorneal area along with prompt elimination of drugs by defense mechanisms of the eye alike reflex blinking and increased tear flow (Patton & Robinson, 1976;Sieg & Robinson, 1977). Because of this, numerous instillations of concentrated eye drops are needed for achieving the anticipated therapeutic effects (Chien, 1992), which may results in poor patient compliance and sometimes causing side effects due to nonproductive absorption of drugs in stomach through the nasolacrimal duct (Mathiowitz et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Development of loteprednol etabonate-loaded cationic nanoemulsified in-situ ophthalmic gel for sustained delivery and enhanced ocular bioavailability

et al. 2016

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A novel cationic nanoemulsified in-situ ophthalmic gel of loteprednol etabonate (LE) was developed to improve the permeability and retention time of formulations for overall improvement of drug's ocular bioavability. Capryol 90 (oil phase), tween 80 (surfactant) and transcutol P (cosurfactant) was selected as formulation excipients to construct pseudoternary phase diagrams and nanoemulsion region was recognized from diagrams. Spontaneous emulsification method was used to manufacture LE nanoemulsion and it was optimized using 3 2 factorial design by considering the amount of oil and the ratio of surfactant to cosurfactant (S mix ) as independent variables and evaluated for various physicochemical properties. Optimized NE was dispersed in Poloxamer 407 and 188 solution to form nanoemulsified sols that were predictable to transform into in-situ gels at corneal temperature. Drug pharmacokinetics of sterilized optimized in situ NE gel, NE-ISG2 [0.69% w/w Capryol 90, 0.99%w/w S mix (3:1), 13% Poloxamer 407, 4% w/w Poloxamer 188] and marketed formulation were assessed in rabbit aqueous humor. The in-situ gels were clear, shear thinning in nature and displayed zeroorder drug release kinetics. NE-ISG2 showed the minimum ocular irritation potential and significantly (p50.01) higher C max and AUC (0-10 h) , delayed T max , extended mean residence time and improved (2.54-fold times) bioavailability compared to marketed formulation. KeywordsLoteprednol etabonate, ocular cationic nanoemulsion, in-situ gel, ex vivo transcorneal permeation, pharmacokinetic study History

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“…It is a common knowledge that the application of eye drops as conventional ophthalmic delivery systems result in poor bioavailability and therapeutic response because of lacrimal secretion and nasolacrimal drainage in the eye (2,3). Most of the drug is drained away from the precorneal area in few minutes.…”

Section: Introductionmentioning

confidence: 99%

Nanoemulsion as a Potential Ophthalmic Delivery System for Dorzolamide Hydrochloride

et al. 2009

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Abstract. Dilutable nanoemulsions are potent drug delivery vehicles for ophthalmic use due to their numerous advantages as sustained effect and high ability of drug penetration into the deeper layers of the ocular structure and the aqueous humor. The aim of this article was to formulate the antiglaucoma drug dorzolamide hydrochloride as ocular nanoemulsion of high therapeutic efficacy and prolonged effect. Thirty-six systems consisting of different oils, surfactants, and cosurfactants were prepared and their pseudoternary-phase diagrams were constructed by water titration method. Seventeen dorzolamide hydrochloride nanoemulsions were prepared and evaluated for their physicochemical and drug release properties. These nanoemulsions showed acceptable physicochemical properties and exhibited slow drug release. Draize rabbit eye irritation test and histological examination were carried out for those preparations exhibiting superior properties and revealed that they were nonirritant. Biological evaluation of dorzolamide hydrochloride nanoemulsions on normotensive albino rabbits indicated that these products had higher therapeutic efficacy, faster onset of action, and prolonged effect relative to either drug solution or the market product. Formulation of dorzolamide hydrochloride in a nanoemulsion form offers, thus, a more intensive treatment of glaucoma, a decrease in the number of applications per day, and a better patient compliance compared to conventional eye drops.

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Vehicle Effects on Ocular Drug Bioavailability II: Evaluation of Pilocarpine

Cited by 111 publications

References 28 publications

Ocular Pharmacokinetics

Ocular Pharmacokinetics

Development of loteprednol etabonate-loaded cationic nanoemulsified in-situ ophthalmic gel for sustained delivery and enhanced ocular bioavailability

Nanoemulsion as a Potential Ophthalmic Delivery System for Dorzolamide Hydrochloride

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