Measurement of drug release from microcarriers by microdialysis

Hitzman, Cory J.; Wiedmann, Timothy S.; Dai, Haiqing; Elmquist, William F.

doi:10.1002/jps.20349

Cited by 30 publications

(22 citation statements)

References 15 publications

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“…The dialysis method is used widely because sampling and media replacement are convenient due to the physical separation of the liposomes from the outer media by a dialyzing membrane. 4,6 This technique in particular mimics in vivo conditions where the nanoparticles are immobilized upon administration, such as following dermal, transdermal, subcutaneous, or intramuscular administration. 3 Various modifications of the basic technique have been employed to assess drug release, especially for the use of hydrophobic drugs, including adjusting the dialysis media based on drug solubility and stability.…”

Section: Discussionmentioning

confidence: 99%

“…An in vitro release profile reveals important information on the structure and behavior of the formulation, possible interactions between the drug and carrier composition, and their influence on the rate and mechanism of drug release. [3][4][5] In comparison to parenteral drug delivery, not much attention has been devoted to the development of a reliable in vitro release technique for topical liposomal formulations, especially those encapsulating hydrophobic compounds. The dialysis release method is a well-established and useful technique to study in vitro release from micro-and nano-particulate delivery systems.…”

Section: Huamentioning

confidence: 99%

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Comparison of in vitro dialysis release methods of loperamide-encapsulated liposomal gel for topical drug delivery

Hua¹

2014

IJN

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Background The purpose of this study was to determine the most appropriate dialysis equilibrium method to assess liposomal gel formulations containing hydrophobic drugs, to give the most accurate indication of drug release. Methods Loperamide hydrochloride-encapsulated liposomes, composed of L-α-phosphatidylcholine and cholesterol (molar ratio of 2:1), were prepared according to the method of dried lipid film hydration. The liposomes were incorporated into a carbopol gel (0.5%, weight/weight). The release of the drug from the nanoparticles was assessed using a number of variations of the dialysis technique, taking into account solubility parameters and formulation. Method 1 (below saturation point) and Method 2 (above saturation point) used a dilution method to evaluate how drug concentration and solubility affects the in vitro drug-release profile of loperamide hydrochloride, while Methods 3 (below saturation point) and 4 (above saturation point) evaluated how drug concentration and the gel base affect the release profile. Results In Method 1, the liposomes showed a rapid release of just over 60% in the first 3 hours and then a slower, sustained release to just over 70% at 24 hours. Method 2 showed a gradual, sustained release profile with the liposomes with 55% release at 24 hours. In Method 3, the liposomes showed a rapid burst release of 98% at 2 hours. In Method 4, the liposomal gel had a rapid release of 60% within 3 hours and then a more gradual, sustained release with 86% release at 24 hours. The free drug suspension in Methods 2 and 4 showed a limited release across the dialysis membrane, in comparison to Methods 1 and 3, which showed a complete release in a timely manner. Conclusion This study has demonstrated that the actual method used for equilibrium dialysis plays a significant role in determining the true characteristics of a topical nanoformulation, with Method 3 providing the most accurate indication of the release of a hydrophobic drug from a topical liposomal formulation.

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Section: Discussionmentioning

confidence: 99%

Section: Huamentioning

confidence: 99%

Comparison of in vitro dialysis release methods of loperamide-encapsulated liposomal gel for topical drug delivery

Hua¹

2014

IJN

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“…The importance of evaluation of the in vitro release characteristics is increasing and it is one of the regulatory requirements. [16][17][18][19] Although in vitro release characteristics are conventionally evaluated by the dialysis method, Franz diffusion cell method, or dispersion method accompanied by centrifugation or filtration after sampling, [20][21][22][23] a standard procedure is lacking. In the dialysis method or Franz diffusion cell method, it is difficult to completely deny the rate limiting of membrane permeation of the drug if the measurement conditions are not selected adequately.…”

mentioning

confidence: 99%

Characterization of a Doxorubicin Liposome Formulation by a Novel <i>in Vitro</i> Release Test Methodology Using Column-Switching High-Performance Liquid Chromatography

Ohnishi

Tomida

Ito

et al. 2014

CHEMICAL & PHARMACEUTICAL BULLETIN

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A novel in vitro release test methodology for a liposome formulation was developed using a columnswitching high-performance liquid chromatography (HPLC) system. Doxorubicin (DXR) liposome formulations were used as a model. A DXR liposome formulation was dispersed into a release medium, and the dispersion fluid was directly injected at predetermined time points into the column-switching HPLC system. To evaluate the release profile, this system can be used for determining the released and encapsulated DXR in the liposome formulation separately. Comparison with a conventional in vitro release test methodology by dialysis revealed that the methodology developed by column-switching HPLC had no rate-limiting process of membrane permeation of the drug (which is occasionally observed in the dialysis method). The in vitro release profiles of DXR liposome formulations were well characterized using the method developed by column-switching HPLC, and different in vitro release characteristics were revealed. The developed method did not require a large amount of sample or a complicated pretreatment. In addition, the developed columnswitching HPLC system was applicable for characterization of the encapsulation profile of liposome formulations.Key words doxorubicin; Doxil ® ; dialysis; solid-phase extraction; encapsulation Several studies of pharmaceutical formulations for drugdelivery systems (DDS), such as liposomes, microspheres, and nanosuspensions, have been conducted. Their advantages, such as targeted/controlled delivery, enhanced efficacy, and reduced toxicity, have been verified. [1][2][3][4] However, the number of approved and marketed pharmaceutical products with DDS technology is limited. The reasons for this are thought to be the difficulty of robust mass production as well as the lack of sophisticated quality control accompanied by a deep understanding of in vitro and in vivo characteristics. With regard to liposome formulations, the enhanced permeability and retention (EPR) effect of polyethylene glycol-conjugated liposomes has been demonstrated in several studies, and are very attractive as passive targeting methods of antitumor agents. [5][6][7][8][9] Considerable efforts are being made for the development of several administration routes for liposomes, such as inhalational, transdermal, and ocular in addition to injection. [10][11][12][13][14] In contrast, analytical technology for liposome formulations may not be sufficiently mature to assure efficacy and safe performance as well as to direct the optimization of formulations or improvements in manufacturing processes. Drug release characteristics are considered to be one of the important properties to assure the performance of liposome formulations. 15)These characteristics may change depending on the lot-to-lot variation of ingredients and/or changes in manufacturing processes such as scale-up. The importance of evaluation of the in vitro release characteristics is increasing and it is one of the regulatory requirements. [16][17][18][19] Although in vitro re...

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“…Furthermore, drug losses may occur during the sampling process, causing errors in in vitro drug release profiles (6,9). Among the methods that belong to the second category are the dialysis sac (3,11), reverse dialysis sac (4,9), and microdialysis techniques (12). The use of small pore size membranes in these techniques solves one of the major limitations of other in vitro drug release techniques: the separation of the drug already released from the drug-loaded nanocarriers from the remaining encapsulated drug (4).…”

Section: Introductionmentioning

confidence: 99%

Assessing the In Vitro Drug Release from Lipid-Core Nanocapsules: a New Strategy Combining Dialysis Sac and a Continuous-Flow System

et al. 2015

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Abstract. The in vitro assessment of drug release from polymeric nanocapsules suspensions is one of the most studied parameters in the development of drug-loaded nanoparticles. Nevertheless, official methods for the evaluation of drug release from submicrometric carriers are not available. In this work, a new approach to assess the in vitro drug release profile from drug-loaded lipid-core nanocapsules (LNC) was proposed. A continuous-flow system (open system) was designed to evaluate the in vitro drug release profiles from different LNC formulations containing prednisolone or clobetasol propionate (LNC-CP) as drug model (LNC-PD) using a homemade apparatus. The release medium was constantly renewed throughout the experiment. A dialysis bag containing 5 mL of formulation (0.5 mg mL −1 ) was maintained inside the apparatus, under magnetic stirring and controlled temperature (37°C). In parallel, studies based on the conventional dialysis sac technique (closed system) were performed. It was possible to discriminate the in vitro drug release profile of different formulations using the open system. The proposed strategy improved the sink condition, by constantly renewing the release medium, thus maintaining the drug concentration farther from the saturated concentration in the release medium. Moreover, problems due to sampling errors can be easily overcome using this semi-automated system, since the collection is done automatically without interference from the analyst. The system proposed in this paper brings important methodological and analytical advantages, becoming a promising prototype semi-automated apparatus for performing in vitro drug release studies from drug-loaded lipid-core nanocapsules and other related nanoparticle drug delivery systems.

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Measurement of drug release from microcarriers by microdialysis

Cited by 30 publications

References 15 publications

Comparison of in vitro dialysis release methods of loperamide-encapsulated liposomal gel for topical drug delivery

Comparison of in vitro dialysis release methods of loperamide-encapsulated liposomal gel for topical drug delivery

Characterization of a Doxorubicin Liposome Formulation by a Novel <i>in Vitro</i> Release Test Methodology Using Column-Switching High-Performance Liquid Chromatography

Assessing the In Vitro Drug Release from Lipid-Core Nanocapsules: a New Strategy Combining Dialysis Sac and a Continuous-Flow System

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