Untitled

Bodmeier, Roland; Sarabia, Rafael E.; Skultety, Paul F.

doi:10.1023/a:1016021115481

Cited by 95 publications

(6 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Buffer species-dependent drug release kinetics of diltiazem from Eudragit RS/RL-coated beads has been reported. Due to the different strength of interaction between the buffer anions and the quaternary ammonium groups of Eudragit RS/RL, the order of drug release in various buffer media was found as follows: acetate > formate > chloride [99]. To achieve a sigmoidal drug release profile, a bead system has been prepared by coating Eudragit RS onto a drug core containing drug and organic acid ( Figure 1B ) [100,101].…”

Section: Ion-sensitive Polymersmentioning

confidence: 99%

pH- and ion-sensitive polymers for drug delivery

Yoshida

Lai

Kwon

et al. 2013

Expert Opinion on Drug Delivery

284

181

View full text Add to dashboard Cite

Introduction Drug delivery systems (DDSs) are important for effective, safe, and convenient administration of drugs. pH- and ion-responsive polymers have been widely employed in DDS for site-specific drug release due to their abilities to exploit specific pH- or ion-gradients in the human body. Areas covered Having pH-sensitivity, cationic polymers can mask the taste of drugs and release drugs in the stomach by responding to gastric low pH. Anionic polymers responsive to intestinal high pH are used for preventing gastric degradation of drug, colon drug delivery and achieving high bioavailability of weak basic drugs. Tumor-targeted DDSs have been developed based on polymers with imidazole groups or poly(β-amino ester) responsive to tumoral low pH. Polymers with pH-sensitive chemical linkages, such as hydrazone, acetal, ortho ester and vinyl ester, pH-sensitive cell-penetrating peptides and cationic polymers undergoing pH-dependent protonation have been studied to utilize the pH gradient along the endocytic pathway for intracellular drug delivery. As ion-sensitive polymers, ion-exchange resins are frequently used for taste-masking, counterion-responsive drug release and sustained drug release. Polymers responding to ions in the saliva and gastrointestinal fluids are also used for controlled drug release in oral drug formulations. Expert opinion Stimuli-responsive DDSs are important for achieving site-specific and controlled drug release; however, intraindividual, interindividual and intercellular variations of pH should be considered when designing DDSs or drug products. Combination of polymers and other components, and deeper understanding of human physiology are important for development of pH- and ion-sensitive polymeric DDS products for patients.

show abstract

Section: Ion-sensitive Polymersmentioning

confidence: 99%

pH- and ion-sensitive polymers for drug delivery

Yoshida

Lai

Kwon

et al. 2013

Expert Opinion on Drug Delivery

284

181

View full text Add to dashboard Cite

show abstract

“…Several researchers have studied the effects of plasticizers when used with various grades of Eudragits (3,5,(11)(12)(13)(14)(15)(16). Dyer and coworkers evaluated, in part, the effect of plasticizers on drug release from film-coated pellets (16).…”

Section: Introductionmentioning

confidence: 99%

The Effects of Plasticizers on the Release of Metoprolol Tartrate from Granules Coated with a Polymethacrylate Film

Okarter¹,

Singla²

2000

Drug Development and Industrial Pharmacy

View full text Add to dashboard Cite

For coating metoprolol tartrate granules, coating dispersions of Eudragit RS 30 D containing 6%, 12%, or 18% (based on polymer weight) of one of the following plasticizers were used: polyethylene glycol 400 (PEG400), propylene glycol (PG), tributyl citrate (TBC), and triethyl citrate (TEC). The release of metoprolol tartrate from these coated granules was determined at pH 1.2 and 7.4. Slower release resulted from the use of each plasticizer, being slower with increasing concentration of the plasticizer. Release was faster with the more water soluble PEG400 and PG than with TBC and TEC. pH-dependent release was observed with PEG400, PG, and TBC, while TEC gave pH-independent release of drug.

show abstract

“…Therefore, drug release from the polymer matrix depends on the exchange between the anions dissolved in the dissolution media and the quaternary ammonium groups of polymer (Wagner & McGinity, 2002 ). Since the dissolution media at pH 1.2 had chloride anions which are less selective to ion exchange than phosphate ion at pH 6.8, the degree of hydration and permeability of polymer matrix decrease at acidic condition (Bodmeier et al., 1996 ; Wagner & McGinity, 2002 ). Some of previous studies also reported that drug release rates from pellets coated with ammonio methacrylate copolymers varies in the dissolution media containing different anions (Knop, 1996 ; Wagner & McGinity, 2002 ).…”

Section: Resultsmentioning

confidence: 99%

Sustained-release solid dispersion of pelubiprofen using the blended mixture of aminoclay and pH independent polymers: preparation and in vitro/in vivo characterization

et al. 2017

View full text Add to dashboard Cite

The present study aimed to develop the sustained-release oral dosage form of pelubiprofen (PEL) by using the blended mixture of 3-aminopropyl functionalized-magnesium phyllosilicate (aminoclay) and pH-independent polymers. The sustained-release solid dispersion (SRSD) was prepared by the solvent evaporation method and the optimal composition of SRSD was determined as the weight ratio of drug: EudragitV R RL PO: EudragitV R RS PO of 1:1:2 in the presence of 1% of aminoclay (SRSD(F6)). The dissolution profiles of SRSD(F6) were examined at different pHs and in the simulated intestinal fluids. The drug release from SRSD(F6) was limited at pH 1.2 and gradually increased at pH 6.8, resulting in the best fit to Higuchi equation. The sustained drug release from SRSD(F6) was also maintained in simulated intestinal fluid at fasted-state (FaSSIF) and fed-state (FeSSIF). The structural characteristics of SRSD(F6) were examined by using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR), indicating the change of drug crystallinity to an amorphous form. After oral administration in rats, SRSD(F6) exhibited the prolonged drug exposure in plasma. For both PEL and PEL-transOH (active metabolite), once a day dosing of SRSD(F6) achieved oral exposure (AUC) comparable to those from the multiple dosing (3 times a day) of untreated drug. In addition, the in vivo absorption of SRSD(F6) was well-correlated with the in vitro dissolution data, establishing a good level A in vitro/in vivo correlation. These results suggest that SRSD(F6) should be promising for the sustained-release of PEL, thereby reducing the dosing frequency.ARTICLE HISTORY

show abstract

Untitled

Abstract: The anionic buffer species and not the pH had a significant effect on the hydration and hence on the drug release from beads coated with the cationic polymers, Eudragit RS and RL.

Cited by 95 publications

References 2 publications

pH- and ion-sensitive polymers for drug delivery

pH- and ion-sensitive polymers for drug delivery

The Effects of Plasticizers on the Release of Metoprolol Tartrate from Granules Coated with a Polymethacrylate Film

Sustained-release solid dispersion of pelubiprofen using the blended mixture of aminoclay and pH independent polymers: preparation and in vitro/in vivo characterization

Contact Info

Product

Resources

About