The physical properties of generic latanoprost ophthalmic solutions are not identical

Miriam Kolko; Peter Koch Jensen

doi:10.1111/aos.13355

The physical properties of generic latanoprost ophthalmic solutions are not identical

Miriam Kolko, Peter Koch Jensen

6 Citations (Scopus)

Abstract

PURPOSE: To compare various characteristics of Xalatan® and five generic latanoprost ophthalmic solutions.

METHODS: Drop size, volume, pH values, buffer capacity, viscosity, hardness of bottles and costs were determined. Drop sizes were measured in triplicates by micropipettes, and the number of drops counted in three separate bottles of each generic product was determined. pH values were measured in triplicates by a calibrated pH meter. Buffer capacity was exploited by titrating known quantities of strong base into 2.5 ml of each brand and interpolated to neutral pH. Kinematic viscosity was determined by linear regression of timed gravity flow from a vertical syringe through a 21-G cannula. The hardness of the bottles was evaluated by gradually increasing tension on a hook placed around each bottle until a drop was expelled reading the tension on an attached spring scale.

RESULTS: Drop sizes and the number of drops in the bottles varied significantly between the generic drugs. The control value of pH in the brand version (Xalatan® ) was markedly lower compared to the generic latanoprost products. Titration of Xalatan® to neutrality required substantially more NaOH compared to the generic latanoprost products. Finally, the viscosity revealed a significant variability between brands. Remarkable differences were found in bottle shapes, bottle hardness and costs of the latanoprost generics.

CONCLUSION: Generic latanoprost eye drops should not be considered identical to the original brand version as regards to drop size, volumes, pH values, buffer capacity, viscosity, hardness of bottles and costs. It is likely that these issues affect compliance and intraocular pressure (IOP)-lowering effect. Therefore, re-evaluation of the requirements for introducing generic eye drops seems reasonable.

Original language	English
Journal	Acta Ophthalmologica
Volume	95
Issue number	4
Pages (from-to)	370-373
Number of pages	4
ISSN	1755-375X
DOIs	https://doi.org/10.1111/aos.13355
Publication status	Published - Jun 2017

Keywords

Antihypertensive Agents
Drug Costs
Drugs, Generic
Glaucoma
Humans
Intraocular Pressure
Ophthalmic Solutions
Prostaglandins F, Synthetic
Tonometry, Ocular
Journal Article

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10.1111/aos.13355

aos.13355Final published version, 284 KB

Cite this

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title = "The physical properties of generic latanoprost ophthalmic solutions are not identical",

abstract = "PURPOSE: To compare various characteristics of Xalatan{\textregistered} and five generic latanoprost ophthalmic solutions.METHODS: Drop size, volume, pH values, buffer capacity, viscosity, hardness of bottles and costs were determined. Drop sizes were measured in triplicates by micropipettes, and the number of drops counted in three separate bottles of each generic product was determined. pH values were measured in triplicates by a calibrated pH meter. Buffer capacity was exploited by titrating known quantities of strong base into 2.5 ml of each brand and interpolated to neutral pH. Kinematic viscosity was determined by linear regression of timed gravity flow from a vertical syringe through a 21-G cannula. The hardness of the bottles was evaluated by gradually increasing tension on a hook placed around each bottle until a drop was expelled reading the tension on an attached spring scale.RESULTS: Drop sizes and the number of drops in the bottles varied significantly between the generic drugs. The control value of pH in the brand version (Xalatan{\textregistered} ) was markedly lower compared to the generic latanoprost products. Titration of Xalatan{\textregistered} to neutrality required substantially more NaOH compared to the generic latanoprost products. Finally, the viscosity revealed a significant variability between brands. Remarkable differences were found in bottle shapes, bottle hardness and costs of the latanoprost generics.CONCLUSION: Generic latanoprost eye drops should not be considered identical to the original brand version as regards to drop size, volumes, pH values, buffer capacity, viscosity, hardness of bottles and costs. It is likely that these issues affect compliance and intraocular pressure (IOP)-lowering effect. Therefore, re-evaluation of the requirements for introducing generic eye drops seems reasonable.",

keywords = "Antihypertensive Agents, Drug Costs, Drugs, Generic, Glaucoma, Humans, Intraocular Pressure, Ophthalmic Solutions, Prostaglandins F, Synthetic, Tonometry, Ocular, Journal Article",

author = "Miriam Kolko and {Koch Jensen}, Peter",

note = "{\textcopyright} 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.",

year = "2017",

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T1 - The physical properties of generic latanoprost ophthalmic solutions are not identical

AU - Kolko, Miriam

AU - Koch Jensen, Peter

PY - 2017/6

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N2 - PURPOSE: To compare various characteristics of Xalatan® and five generic latanoprost ophthalmic solutions.METHODS: Drop size, volume, pH values, buffer capacity, viscosity, hardness of bottles and costs were determined. Drop sizes were measured in triplicates by micropipettes, and the number of drops counted in three separate bottles of each generic product was determined. pH values were measured in triplicates by a calibrated pH meter. Buffer capacity was exploited by titrating known quantities of strong base into 2.5 ml of each brand and interpolated to neutral pH. Kinematic viscosity was determined by linear regression of timed gravity flow from a vertical syringe through a 21-G cannula. The hardness of the bottles was evaluated by gradually increasing tension on a hook placed around each bottle until a drop was expelled reading the tension on an attached spring scale.RESULTS: Drop sizes and the number of drops in the bottles varied significantly between the generic drugs. The control value of pH in the brand version (Xalatan® ) was markedly lower compared to the generic latanoprost products. Titration of Xalatan® to neutrality required substantially more NaOH compared to the generic latanoprost products. Finally, the viscosity revealed a significant variability between brands. Remarkable differences were found in bottle shapes, bottle hardness and costs of the latanoprost generics.CONCLUSION: Generic latanoprost eye drops should not be considered identical to the original brand version as regards to drop size, volumes, pH values, buffer capacity, viscosity, hardness of bottles and costs. It is likely that these issues affect compliance and intraocular pressure (IOP)-lowering effect. Therefore, re-evaluation of the requirements for introducing generic eye drops seems reasonable.

AB - PURPOSE: To compare various characteristics of Xalatan® and five generic latanoprost ophthalmic solutions.METHODS: Drop size, volume, pH values, buffer capacity, viscosity, hardness of bottles and costs were determined. Drop sizes were measured in triplicates by micropipettes, and the number of drops counted in three separate bottles of each generic product was determined. pH values were measured in triplicates by a calibrated pH meter. Buffer capacity was exploited by titrating known quantities of strong base into 2.5 ml of each brand and interpolated to neutral pH. Kinematic viscosity was determined by linear regression of timed gravity flow from a vertical syringe through a 21-G cannula. The hardness of the bottles was evaluated by gradually increasing tension on a hook placed around each bottle until a drop was expelled reading the tension on an attached spring scale.RESULTS: Drop sizes and the number of drops in the bottles varied significantly between the generic drugs. The control value of pH in the brand version (Xalatan® ) was markedly lower compared to the generic latanoprost products. Titration of Xalatan® to neutrality required substantially more NaOH compared to the generic latanoprost products. Finally, the viscosity revealed a significant variability between brands. Remarkable differences were found in bottle shapes, bottle hardness and costs of the latanoprost generics.CONCLUSION: Generic latanoprost eye drops should not be considered identical to the original brand version as regards to drop size, volumes, pH values, buffer capacity, viscosity, hardness of bottles and costs. It is likely that these issues affect compliance and intraocular pressure (IOP)-lowering effect. Therefore, re-evaluation of the requirements for introducing generic eye drops seems reasonable.

KW - Antihypertensive Agents

KW - Drug Costs

KW - Drugs, Generic

KW - Glaucoma

KW - Humans

KW - Intraocular Pressure

KW - Ophthalmic Solutions

KW - Prostaglandins F, Synthetic

KW - Tonometry, Ocular

KW - Journal Article

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DO - 10.1111/aos.13355

M3 - Journal article

C2 - 28229536

SN - 1755-375X

VL - 95

SP - 370

EP - 373

JO - Acta Ophthalmologica

JF - Acta Ophthalmologica

IS - 4

ER -

The physical properties of generic latanoprost ophthalmic solutions are not identical

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Keywords

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