Design of pH-independent controlled release matrix tablets for acidic drugs

Rao, Venkatramana M.; Engh, Kevin; Qiu, Yihong

doi:10.1016/s0378-5173(02)00622-1

Cited by 77 publications

(47 citation statements)

References 11 publications

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“…These studies demonstrated that the pH of the microenvironment (i.e., pH of diffusion layer), and therefore the dissolution of weak acidic and basic drugs, can be modulated. Because of this finding, the dissolution of poorly soluble weak acidic and basic drugs in both immediate-release (9,10) and controlled-release (11)(12)(13)(14)(15)(16)(17) dosage forms has been successfully enhanced or retarded by the application of the concept of microenvironmental pH modulation.…”

Section: Introductionmentioning

confidence: 99%

Enhancing and Sustaining AMG 009 Dissolution from a Matrix Tablet Via Microenvironmental pH Modulation and Supersaturation

Kyad

Kiang

et al. 2011

AAPS PharmSciTech

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Abstract. The objective of this study was to investigate the combined effect of pH modifiers and nucleation inhibitors on enhancing and sustaining the dissolution of AMG 009 tablet via supersaturation. Several bases and polymers were added as pH modifiers and nucleation inhibitors, respectively, to evaluate their impact on the dissolution of AMG 009 tablets. The results indicate that sodium carbonate, among the bases investigated, enhanced AMG 009 dissolution the most. HPMC E5 LV, among the nucleation inhibitors tested, was the most effective in sustaining AMG 009 supersaturation. The release of AMG 009 went from 4% for tablets which did not contain both sodium carbonate and HPMC E5 LV to 70% for the ones that did, resulting in a 17.5-fold increase in the extent of dissolution. The effect of compression force and disintegrant on the dissolution of tablets were also evaluated. The results indicate that compression force had no effect on AMG 009 release. The addition of disintegrating agents, on the other hand, decreased the dissolution of AMG 009.

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Section: Introductionmentioning

confidence: 99%

Enhancing and Sustaining AMG 009 Dissolution from a Matrix Tablet Via Microenvironmental pH Modulation and Supersaturation

Kyad

Kiang

et al. 2011

AAPS PharmSciTech

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“…Rao et al have studied the influence of changes in the pH on the release kinetics of active substances. Following their study, they identified significant differences regarding the yield of the active compound release with a pH of 6.8, in comparison to those with a pH of 1 [21].…”

Section: Discussionmentioning

confidence: 99%

“…The silica gels were obtained using a two-stage method in accordance with the methods described in the literature [6,21,22]. In the first step the sol was obtained by typical methods of synthesis using two different precursors, tetraethoxysilane and tetramethoxysilane.…”

Section: Encapsulation Stagementioning

confidence: 99%

An in vitro study of the release capacity of the local anaesthetics from siloxane matrices

Preda

Rogobete

Săndesc

et al. 2016

Rom J Anaesth Int Care

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Aims. In the field of anaesthesia and intensive care, the controlled release systems capable of delivering constantly local anaesthetics are of interest because of the advantages brought to pain management. In this paper we presented the release profiles by usage of siloxane matrices of two common local anaesthetics, lidocaine and bupivacaine, analysed in vitro.Methods. The siloxane matrices were obtained in accordance with the methods described in the specialized literature, tetraethoxysilane (TEOS) and tetramethoxysilane (TMOS) were used as precursors. Lidocaine and bupivacaine were encapsulated in the synthesized gels. The controlled release was performed in vitro artificial systems in which temperature (30°C, 36.5°C, 40°C) and pH (6, 7, 8) have varied.Results. Following the analysis of the artificial systems similar profiles were highlighted for both local anaesthetics. Statistically significant differences were identified (p < 0.05) for systems where the release occurred at temperatures above 36.5°C. There were no statistically significant differences regarding the influence of pH, the type of the entrapped anaesthetic or the type of the precursor used in the synthesis of siloxane matrices.Conclusions. According to this experimental study, the pH, the type of precursor or the type of anaesthetic does not statistically influence the release profile from the studied system. In conclusion, these systems are promising for obtaining pharmaceutical preparations which can be used in current clinical practice. Several studies on controlled release siloxane systems should be carried out both in vitro and in vivo in order to exclude possible toxicity and histopathological effects.

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“…They showed a slight increase in weight up to 65.4, 107 and 130 % after 2 h in acidic medium for PMH1, PMH2 and PMH3, respectively. It is worth mentioning that the elevated micro-environmental pH provided by the dissolved EE in the swollen gel layer (22) supported the ionization of SAH within the tablet matrix and, hence, its interaction with EE. This was confirmed by dispersing amounts of EE equivalent to those found in the tablets (45.5, 109 and 136.5 mg) in 1 mL of 0.1 mol L -1 HCl (pH 1.2) and by measurement of the pH of these solutions.…”

Section: Degree Of Tablet Swellingmentioning

confidence: 95%

Some variables affecting the characteristics of Eudragit E-sodium alginate polyelectrolyte complex as a tablet matrix for diltiazem hydrochloride

Yusif¹,

Hashim²,

El-Dahan³

2014

Acta Pharmaceutica

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Modification of polymer properties can be achieved by copolymerization or derivatization, a strategy that was successfully applied in the past. However, this approach has the major drawback that new chemical entities are introduced with an unknown toxicological profile. Before these products can be evaluated in animals and also in human clinical trials, a lot of time and resources must be spent to assess their safety. To overcome this problem, physical modification of the polymer, rather than chemical, is a sound approach. In this respect, polyelectrolyte complexes (PECs) may provide a valuable tool to design drug delivery systems with specific physicochemical properties. PECs obtained Eudragit E (EE)-sodium alginate (SA) polyelectrolyte complexes (PECs) were prepared at pH 4 and 5.8 using sodium alginate of high (SAH) and low viscosity (SAL). The optimum EE-SA complexation mass ratio was determined using viscosity measurements. Interactions between EE and SA in PECs were characterized by Fourier transform infra-red spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Diltiazem hydrochloride (DTZ HCl) tablets were prepared using the prepared EE-SA PECs and their physical mixtures at different ratios as matrices. Tablets were evaluated for swelling characteristics and in vitro drug release. Tablets containing EE-SAH physical mixtures of ratios (1.5:1 and 1:3) as matrices were effective in achieving sustained release of DTZ HCl, where the percent drug released was significantly (p < 0.05) decreased compared to that from tablets either containing the same ratios of EE-SAL physical mixtures or the preformed EE--SAH and EE-SAL PECs.

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Design of pH-independent controlled release matrix tablets for acidic drugs

Cited by 77 publications

References 11 publications

Enhancing and Sustaining AMG 009 Dissolution from a Matrix Tablet Via Microenvironmental pH Modulation and Supersaturation

Enhancing and Sustaining AMG 009 Dissolution from a Matrix Tablet Via Microenvironmental pH Modulation and Supersaturation

An in vitro study of the release capacity of the local anaesthetics from siloxane matrices

Some variables affecting the characteristics of Eudragit E-sodium alginate polyelectrolyte complex as a tablet matrix for diltiazem hydrochloride

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