Characterisation of commercially available theophylline sustained- or controlled-release systems: in-vitro drug release profiles

Po, A. Li Wan; Wong, Lynn; Gilligan, C.A.

doi:10.1016/0378-5173(90)90391-g

Cited by 21 publications

(6 citation statements)

References 17 publications

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“…For example, the cumulative release of ketoprofen from a reached 42.3% after 12 h at pH 10.0, while it only reached 2.5% under the same condition at pH 1.2. These observations of higher release rates found at the alkali pH values were consistent with results reported by others 22. It seemed that the drug‐saccharide conjugates had a low degree of swelling in the acidic medium and the drug was protected against hydrolytic attack 23–25.…”

Section: Resultssupporting

confidence: 91%

“…These observations of higher release rates found at the alkali pH values were consistent with results reported by others. 22 It seemed that the drug-saccharide conjugates had a low degree of swelling in the acidic medium and the drug was protected against hydrolytic attack. [23][24][25] Indeed, it was likely that alkaline conditions favor swelling that in turn might facilitate drug release.…”

Section: Effect Of Ph On Drug Releasementioning

confidence: 99%

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In vitro controlled release of polymeric drug‐saccharide conjugates with ketoprofen, ibuprofen, and naproxen pendants

Xie

Branford-White

et al. 2011

J of Applied Polymer Sci

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Polymerizable monomers of glucose and three types of nonsteroidal anti-inflammatory drugs were prepared. Free radical polymerization of the resulting monomers was carried out in DMF. The polymers with drug pendent were characterized using FTIR, NMR, and GPC spectroscopy. Following hydrolysis of polymeric drug-saccharide conjugates at 37 C, the cumulative released of naproxen, ibuprofen, and ketoprofen were 70, 55, and 30% after 10 days, respectively. Half-lives (t 1/2 ) of the copolymers were calculated through the first 12 h and these were found to be 4.2, 5.3, and 7.8 h, suggesting a slow and sustained drug release mechanism. The drug release profiles were also carried out at different pH, temperature, and ionic strength and solution varieties. It was concluded that different release profiles occurred and were dependent on temperature and pH. It was apparent that the polymeric drug-saccharide conjugate had the potential to be developed as a system that enhances drug delivery.

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Section: Resultssupporting

confidence: 91%

Section: Effect Of Ph On Drug Releasementioning

confidence: 99%

In vitro controlled release of polymeric drug‐saccharide conjugates with ketoprofen, ibuprofen, and naproxen pendants

Xie

Branford-White

et al. 2011

J of Applied Polymer Sci

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“…The amount of drug released depends not only on the two diffusion processes of water penetration through the hydrated matrix into the nonhydrated core and diffusion of the dissolved drug through the hydrated matrix, but also on the erosion rate of the hydrated layer. For erodible tablets, drug release is determined by the erosion rate of the device (17). Because the erosion rate of the tablets was slow and not significantly affected by the given range of the flow rate in this study, the drug release of Uniphyllin tablets was mainly controlled by the rate of water permeation and drug diffusion out of the gel matrix.…”

Section: Drug Release From Er Theophylline Tablets and Capsulesmentioning

confidence: 98%

In Vitro Dissolution Studies of Immediate-Release and Extended-Release Formulations Using Flow-Through Cell Apparatus 4

Qiu¹,

Wang²,

Li³

2014

Dissolution Technol.

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The aims of this study were to evaluate the dissolution performance of solid dosage forms using the open and closed modes of the FTC Apparatus 4 under different flow rates and provide examples to demonstrate the advantages of the FTC method, in particular the possibility of changing the pH during experiments, in studying the release mechanisms of extended-release products. Immediate-release (IR) paracetamol and extended-release (ER) theophylline formulations were used in this study. Results from commercially available IR paracetamol tablets using FTC Apparatus 4 have shown similar dissolution behavior in the closed and open systems, reflecting well-maintained apparent sink conditions and controlled hydrodynamics in the test cells. The flow rate of FTC Apparatus 4 significantly affected the disintegration process of IR tablets. This information can be used as a discriminating tool to support formulation development and to set quality control standards and specifications. To mimic the continuous absorption of theophylline during the passage at different pH values through the whole gastrointestinal tract, dissolution tests were conducted using FTC Apparatus 4 with pH-dependent media for three different commercially available theophylline formulations. Two formulations of Uniphyllin 200-mg tablets and Nuelin SA 175-mg tablets provided a constant release rate during the course of medium pH changes, and their release behavior was predicted with accuracy by appropriate mathematical models. However, wide intervariability and biphasic release in the dissolution profiles were found for Slo-Phyllin 125-mg capsules.

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“…To further investigate the mechanism of drug release from carriers; Zero-order, First-order, and Peppas-Sahlin models were examined. Zero-order model is utilized where drug release is controlled by matrix degradation 42 :…”

Section: Understanding Of Drug Release Mechanisms: Strategy To Invementioning

confidence: 99%

Controlled release from polyurethane films: Drug release mechanisms

Abbasnezhad

Zirak

Shirinbayan

et al. 2020

J of Applied Polymer Sci

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In this study, polyurethane‐films loaded with diclofenac were used to analyze the drug release kinetics and mechanisms. For this purpose, the experimental procedures were developed under static and dynamic conditions with different initial drug loads of 10, 20, and 30%. In the dynamic condition, to better simulate the biological flow, drug release measurements were investigated at flow rates of 7.5 and 23.5 ml/s. These values indicate the flow rate of the internal carotid artery (ICA) for a normal state of a body and for a person during the exercise, respectively. The experimental data were analyzed and adjusted by Higuchi, Korsmeyer–Peppas, First‐order, zero‐order, and Peppas–Sahlin models in order to understand the mechanisms contributed. Finally, drug release mechanisms were specified by investigating the model correlation coefficients. Experimental results showed that increasing the flow rate and initial drug loads enhance drug liberation. In addition, the rate of release is more influenced by the drug dosage in the static state. The analysis revealed that diffusion, burst, and osmotic pressure are the principal mechanisms contributed. Moreover, Fickian type was the dominant mechanism at all duration of release. However, it was discovered using Peppas–Sahlin model that the contribution of the diffusion mechanism decreases with increasing flow rate and initial dosage. Furthermore, the tests at different drug dosages showed that the number of stages in medication release profile is independent of the flow rate and the medicine percentage. One can conclude that the drug release kinetic in static state is more influenced by drug dosage compared with dynamic state.

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Characterisation of commercially available theophylline sustained- or controlled-release systems: in-vitro drug release profiles

Cited by 21 publications

References 17 publications

In vitro controlled release of polymeric drug‐saccharide conjugates with ketoprofen, ibuprofen, and naproxen pendants

In vitro controlled release of polymeric drug‐saccharide conjugates with ketoprofen, ibuprofen, and naproxen pendants

In Vitro Dissolution Studies of Immediate-Release and Extended-Release Formulations Using Flow-Through Cell Apparatus 4

Controlled release from polyurethane films: Drug release mechanisms

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