Introduction and Overview of Oral Controlled Release Formulation Design

Wen, Hu; Park, Kinam

doi:10.1002/9780470640487.ch1

Cited by 50 publications

(53 citation statements)

References 110 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During diffusion studies with a large volume of VSF and SSF (80 mL), there is a difference in the initial rate of diffusion based on the size of the suppositories; however, almost all of the encapsulated TFV diffuses out of the suppositories in 24 h. For dissolution in 80 mL of medium, the higher rates of diffusion in VSF as compared to SSF can be explained by the greater solubility of tenofovir (pK a 3.8 (acidic) and 6.7 (basic)) in a medium of pH 4–6.5 (data not shown). The rate of drug diffusion from a delivery matrix partly depends on the concentration of drug in the saturated layer around the matrix, which depends on the solubility of the drug [ 38 ]; hence, tenofovir diffuses faster out of the carrageenan matrix into VSF as compared to SSF. The release rates in 5 mL of VSF are lower than in 80 mL, due to the saturation of the VSF medium surrounding the suppositories.…”

Section: Discussionmentioning

confidence: 99%

Release of Tenofovir from Carrageenan-Based Vaginal Suppositories

2014

View full text Add to dashboard Cite

Microbicides are an active area of research for HIV prevention, being developed as a woman-initiated method of prevention during unprotected coitus. Along with safety and efficacy, assessing and improving compliance is a major area of research in microbicide development. We have produced microbicide prototypes in the form of semisoft vaginal suppositories prepared from carrageenan and conducted both qualitative and quantitative studies using these prototypes to determine the physical properties that drive acceptability and possibly adherence. In order to ensure that the suppositories function as effective drug delivery vehicles, we have conducted in vitro dissolution studies in water, vaginal simulant fluid (VSF) and semen simulant fluid (SSF) with suppositories loaded with the antiretroviral drug, tenofovir (TFV). TFV was released via diffusion and matrix erosion in water or by diffusion out of the matrix in VSF and SSF. Diffusion studies were conducted in two different volumes of VSF and SSF. The volume of VSF/SSF into which TFV diffused and the size of the suppositories determined the rate of diffusion from the suppositories. About 45%–50% of the encapsulated TFV diffused out of the suppositories within the first two hours, irrespective of suppository size, diffusion medium (VSF/SSF) and the volume of medium. Prior work indicates that a short waiting period between insertion and coitus is highly desired by women; present data suggest our microbicide prototypes have rapid initial release followed by a slow release curve over the first 24 h.

show abstract

Section: Discussionmentioning

confidence: 99%

Release of Tenofovir from Carrageenan-Based Vaginal Suppositories

2014

View full text Add to dashboard Cite

show abstract

“…Mean absolute oral bioavailability is ~100%, with no evidence of marked first‐pass metabolism . The exact GI site of perampanel absorption has not been investigated, but based on the rapid absorption, a site in the upper GI tract is likely …”

Section: Pharmacokinetics Of Perampanel In Adultsmentioning

confidence: 99%

The clinical pharmacology profile of the new antiepileptic drug perampanel: A novel noncompetitive AMPA receptor antagonist

2014

View full text Add to dashboard Cite

SUMMARYThe clinical pharmacology profile of a drug critically determines its therapeutics, and this review summarizes the characteristics associated with the antiepileptic drug (AED) perampanel. A PubMed literature search was performed for perampanel. Congress abstract data are included where necessary and Eisai Ltd provided access to unpublished data on file. After oral ingestion, perampanel is rapidly absorbed and peak plasma concentrations occur 0.5-2.5 h later; its bioavailability is~100%. Although the rate of perampanel absorption is slowed by food co-ingestion, the extent absorbed remains unchanged; therefore, perampanel can be administered without regard to meal times. The pharmacokinetics of perampanel are linear and predictable over the clinically relevant dose range (2-12 mg); perampanel is 95% protein-bound to albumin and a1-acid glycoprotein. Perampanel is extensively metabolized (>90%) in the liver, primarily by cytochrome P450 (CYP) 3A4, to various pharmacologically inactive metabolites. In healthy volunteers, the apparent terminal half-life is~105 h, whereas the calculated effective half-life is 48 h. These half-life values allow for once-daily dosing, which will aid patient compliance and in the event of a missed dose, will have minimal impact on seizure control. In healthy volunteers prescribed carbamazepine, halflife decreases to 25 h. Clearance values are not significantly different in adolescents (~13.0 ml/min) and the elderly (~10.5 ml/min) compared with adults (10.9 ml/min). Perampanel has minimal propensity to cause pharmacokinetic interactions. However, it is the target of such interactions and CYP3A4-inducing AEDs enhance its clearance; this can be used to advantage because dose titration can be faster and thus optimum therapeutic outcome can be achieved sooner. Perampanel 12 mg, but not 4 or 8 mg, enhances the metabolism of the progesterone component of the oral contraceptive pill, necessitating the need for an additional reliable contraceptive method. Overall, perampanel has a favorable clinical pharmacology profile, which should aid its clinical use.

show abstract

“…The mechanisms used to achieve a controlled release in oral drug delivery systems are based on diverse and complex principles such as dissolution, diffusion, osmosis, swelling, and erosion. The development of push-pull osmotic pump systems and diffusion-or dissolution-controlled monolithic devices or reservoir systems has been widely applied to many extended-release (ER) oral dosage forms 1 .…”

Section: Introductionmentioning

confidence: 99%

Physiologically Based Pharmacokinetic Modeling for Substitutability Analysis of Venlafaxine Hydrochloride Extended-Release Formulations Using Different Release Mechanisms: Osmotic Pump Versus Openable Matrix

Lin

Sun

Zhang

et al. 2016

Journal of Pharmaceutical Sciences

Self Cite

View full text Add to dashboard Cite

A Food and Drug Administration-approved generic oral product of venlafaxine hydrochloride (HCl) extended-release (ER) tablets has used a release mechanism based on an openable matrix, which is different from the push-pull osmotic pump system of its reference-listed drug. In an extreme case, a delay in the bursting of the openable matrix may be considered a product failure mode that alters the intended profile of systemic exposure. A physiologically based pharmacokinetic absorption model was established and verified to simulate the pharmacokinetic profiles after a single-dose oral administration of ER venlafaxine HCl tablets based on an osmotic pump or openable matrix design. This model adequately predicted the observed human mean pharmacokinetic metrics with <20% difference between the predicted and observed data. Based on the modeling and simulation results, Cmax and AUCt of the venlafaxine openable matrix tablets were entirely within the bioequivalence acceptance limits (i.e., 80%-125%) when the lag time varied from 0 to 4 h and using drug-release profiles under most dissolution conditions. The results indicated that a bioinequivalence risk is minimal for a delayed onset of drug release from the approved generic venlafaxine HCl ER tablets with an openable matrix design, supporting its substitutability to the reference product.

show abstract

Introduction and Overview of Oral Controlled Release Formulation Design

Cited by 50 publications

References 110 publications

Release of Tenofovir from Carrageenan-Based Vaginal Suppositories

Release of Tenofovir from Carrageenan-Based Vaginal Suppositories

The clinical pharmacology profile of the new antiepileptic drug perampanel: A novel noncompetitive AMPA receptor antagonist

Physiologically Based Pharmacokinetic Modeling for Substitutability Analysis of Venlafaxine Hydrochloride Extended-Release Formulations Using Different Release Mechanisms: Osmotic Pump Versus Openable Matrix

Contact Info

Product

Resources

About