Drug Release From Hydrophilic Matrices. 2. A Mathematical Model Based on the Polymer Disentanglement Concentration and the Diffusion Layer

Ju, Robert T.C.; Nixon, Phillip R.; Patel, Mahesh; Tong, Donald M.

doi:10.1002/jps.2600841214

Cited by 98 publications

(48 citation statements)

References 30 publications

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“…This sequence of steps, suggested by Siepmann et al [56], is coherent with a space distribution of the polymer chains as described by Ju et al [57,58], who identified several regions in a hydrogel-based matrix exposed to a water-based dissolution medium:…”

supporting

confidence: 78%

Swellable Hydrogel-based Systems for Controlled Drug Delivery

Caccavo¹,

Cascone²,

Lamberti³

et al. 2016

Smart Drug Delivery System

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The controlled delivery of drugs can be effectively obtained using systems based on hydrogels. Tablets, to be orally administered, represent the simplest and the most traditional dosage systems based on hydrogel. Their formulation and preparation require to mix and to compress, in proper ratios, various excipients, including a swellable polymer and a drug. Carriers for controlled release systems are usually cross-linked polymers able to form hydrogels that show peculiar release mechanisms, where both diffusion and tablet swelling play important roles.When a dry swellable hydrogel-based matrix is immersed in a physiological fluid, this starts to penetrate inside the polymeric hydrophilic matrix. When a certain solvent concentration is reached, the polymeric chains unfold due to a glass-rubber transition, and a gel-like layer is formed. In the swollen region, the drug molecules can easily diffuse toward the outer dissolution medium, once they are dissolved. The polymer network became extremely hydrated where the swollen matrix is in contact with the outer medium, and processes like chain disentanglement take place, "eroding" the matrix.This chapter is focused on the analysis of the state of the art about the uses of carriers for controlled release systems composed by hydrogel-based matrices. This analysis has been performed studying in deep both the experimental and the modeling techniques which have been investigated over the years to characterize all the phenomena involved during the drug release.

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supporting

confidence: 78%

Swellable Hydrogel-based Systems for Controlled Drug Delivery

Caccavo¹,

Cascone²,

Lamberti³

et al. 2016

Smart Drug Delivery System

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“…This machanism has been extensively described in literature (Colombo et al 1995;Gao et al 1995;Ju et al 1995aJu et al , 1995bPham and Lee 1994;Tahara et al 1995). The release pro le was shown to be almost linear up to a Lf release of »80%.…”

Section: Formulation Studiesmentioning

confidence: 80%

Design and Fungicidal Activity of Mucoadhesive Lactoferrin Tablets for the Treatment of Oropharyngeal Candidosis

et al. 2002

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Lactoferrin (Lf) is a potential drug candidate for the treatment of oropharyngeal Candida infections. However, for an effective therapeutic treatment an appropriate dosage form is required. Therefore a mucoadhesive tablet for buccal application was developed. Tablets of sufficient strength could be produced on high speed tabletting machines, but they could only be obtained when the protein contained at least 7% moisture. The tablet contained sodium alginate both for its release-controlling properties as well as for its mucoadhesive properties. Furthermore, phosphate buffer was added to keep the pH of the saliva in the mouth within the range of 6.5 to 7.5. In this pH range, Lf has shown to have its highest activity against Candida growth inhibition. The tablet formulation containing Lf had the same antifungal properties as compared with Lf alone, because in most cases identical inhibitory concentrations were observed against several clinical isolates of Candida albicans and Candida glabrata. In human volunteers the tablets, containing 250 mg Lf and placed in each pouch, were able to keep the Lf concentration in the saliva at effective levels for at least 2 hr, while the pH of the saliva remained within the desired range. We concluded that the developed mucoadhesive tablet can improve the therapeutic efficacy of Lf and that it is suitable for further clinical research.

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“…Hydration is accompanied by a progressive plasticization of HPMC leading to swelling and, as the chains uncoil and extend, more locations become available for hydrogen bonding and further molecular entanglements. [15][16][17] The overall result is an increase in the thickness of the gel layer surrounding the matrix, which retards disintegration and prevents further rapid water penetration into the matrix.…”

Section: Lag Time and In Vitro Drug Release Profile Of Prtsmentioning

confidence: 99%

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Reddy¹

2016

AJP

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Aim: The main objective of the present investigation was to formulate and characterize an oral pulsatile drug delivery system of flurbiprofen, for time dependent release, based on chronomodulated approach for the management of rheumatoid arthritis. Settings and Design: The drug delivery system was designed to deliver the drug with a lag time to release the drug when it could be most needful to patients of rheumatoid arthritis. Materials and Methods: Rapid release core tablets of flurbiprofen were prepared by wet granulation method with explotab as superdisintegrant. Then the press coated pulsatile tablets were formulated using different grades of hydroxypropyl methylcellulose (HPMC) E5, E15, and E50 in varying ratios. Pulsatile tablets were evaluated for pre-and post-compressional parameters. Then the tablets were optimized based on in vitro dissolution studies and lag time for drug release. Statistical Analysis used: One sample t-test was computed to compare the mean lag time obtained with different formulations with a standard of 6 h (360 min) as required time lag between administration of the dosage and drug release. Results: Core tablet formulated with explotab 4% showed 76.18 ± 0.27% release in 10 min it was suitable for formulating into pulsatile release tablets. The formulation containing HPMC E50 at 1:2 ratio of core to coat has shown lag time of 6 h; thus, it was optimized and compiled with chronotherapeutic objective of rheumatoid arthritis. Conclusions: Pulsatile tablets of flurbiprofen were successfully formulated which provided a desirable lag time followed by desirable drug release.

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Drug Release From Hydrophilic Matrices. 2. A Mathematical Model Based on the Polymer Disentanglement Concentration and the Diffusion Layer

Cited by 98 publications

References 30 publications

Swellable Hydrogel-based Systems for Controlled Drug Delivery

Swellable Hydrogel-based Systems for Controlled Drug Delivery

Design and Fungicidal Activity of Mucoadhesive Lactoferrin Tablets for the Treatment of Oropharyngeal Candidosis

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