Yisheng Chen

Novast Labs. Ltd

High-barrier-to-entry generic drugs are difficult to make because of the relatively complex product design. Requirements of specification and bioequivalence are difficult to meet if the product is not fully understood and controlled. Currently, the accessibility of high-barrier-to-entry drug products in China's market is low. However, the country's...

This chapter discusses various important factors that should be considered in selecting containers for solid oral dosage forms. For product protection purposes, the material properties of both the packaging components and the products should be considered together by scientific approaches to ensure that the selected containers can provide the inten...

A dissolution test is a comparative tool for measuring the in vitro performance of solid oral dosage forms, either as a surrogate for evaluating the in vivo drug absorption or in quality control of products. The use as a surrogate for in vivo evaluation is possible only when valid in vitro–in vivo correlation has been established for a product, and...

The fundamental theories of diffusion and solid dissolution are reviewed in this chapter. Diffusion is a process by which small particles such as atoms and molecules are transported from a region of higher concentration to a region of lower concentration by random motion of the particles. This process can be described by Fick’s first and second law...

Quality equivalency evaluation for generic products is a systematic initiative started since 2012 by CFDA to improve the quality of generic products, and ultimately to achieve the inter-changeability of generic products and innovators. Equivalency evaluation can ensure the clinical equivalency between generic and brand products, the concept of qual...

This chapter discusses three main topics. First, this work discusses determination of water vapor transmission rate (WVTR) of pharmaceutical containers using different methods including steady-state method, single weight gain method, and estimation based on literature data of materials. Reliable container WVTR can be obtained from the steady-state...

Developing Solid Oral Dosage Forms: Pharmaceutical Theory and Practice, Second Edition illustrates how to develop high-quality, safe, and effective pharmaceutical products by discussing the latest techniques, tools, and scientific advances in preformulation investigation, formulation, process design, characterization, scale-up, and production opera...

A multilayer solid pharmaceutical dosage form, comprising a core having active ingredients, a first layer of sustained release coating covering the core, a drug layer having active ingredients and covering the first layer of sustained release coating, and a second layer of sustained release coating covering the drug layer.

We hypothesize and demonstrate that artificial neural networks (ANN) can perform better than multiple linear regression models in overcoming the limitations of the current TNM staging system for predicting the overall survival time of patients with non-small cell lung cancer (NSCLC). Better prognostication of survival was achieved by including addi...

USP general chapter Containers-Performance Testing < 671 > was revised recently, and this Stimuli article explains how and why the revisions to <671> were made. The new method in the proposed revision to < 671 > provides a test for determining the moisture vapor transmission rate (MVTR) of the container-closure system. This test is capable of diffe...

This chapter provides a review of the fundamental theory of diffusion, and approaches for the application of the theory to develop solutions for specific problems in pharmaceutical sciences. Adsorption of diffusing molecules in some systems, such as in a reinforced polymer matrix or onto solids in suspensions, can occur during the diffusion process...

Immediate-release (IR) dosage forms are designed to allow drugs to dissolve freely in the gastrointestinal contents, with no intention of delaying or prolonging the dissolution/absorption of the drugs upon administration. IR products could be rapidly dissolving or slowly dissolving, depending on the intrinsic dissolution rate of drug substances. If...

This chapter focuses on the science-based selection of containers and/or packaging materials for protection of solid oral dosage forms. Containers can be classified by dosage forms for which they are intended, by product contact, by container properties, or by purpose of use. Classifications can be based on dosage forms, such as injectable or solid...

The Food and Drug Administration (FDA) has a complex organization for review and approval of new drug applications (NDAs) and abbreviated new drug applications (ANDAs). During the new drug review process, the Office of Pharmaceutical Sciences is involved in the review of the Chemistry, Manufacturing and Controls (CMC) information. After approval, t...

This book is intended for pharmaceutical professionals engaged in research and development of oral dosage forms. It covers essential principles of physical pharmacy, biopharmaceutics and industrial pharmacy as well as various aspects of state-of-the-art techniques and approaches in pharmaceutical sciences and technologies along with examples and/or...

The objective of this study was to investigate the effects of experimental conditions for measuring the water vapor transmission rate (WVTR) of high-density polyethylene (HDPE) bottles using a steady-state sorption method. Bottles were filled with desiccant, closed with caps and heat induction sealed, and then stored in stability chambers at contro...

Maltodextrins were chosen as model excipients because maltodextrins possess a series of molecular weights that showed systematically changing consolidation mechanisms. As maltodextrin molecular weight increases, the plasticity of the material increases. Three commercial grades of Maltrin (M040, M100, and M150) were used to prepare binary powder mix...

Magnesium stearate is widely used as a lubricant in pharmaceutical dosage forms. A film of magnesium stearate, or other lubricant, around individual granules is generally considered to cause the softening of tablets. Maltodextrins were chosen as model excipients since maltodextrins possessing a series of molecular weights showed systematically chan...

For pharmaceutical solid oral dosage forms, it is well recognized that the most common cause for a packaged product failing to meet its specification is its instability as a result of moisture uptake (1–3). The failure is usually related to out-of-specification or out-of-range values in any or combination of the following quality attributes: assay,...

Solid dispersions using Pluronic F-68 as a carrier were studied for improving the dissolution and bioavailability of ABT-963, a poorly water-soluble compound. The solid dispersions were prepared either by evaporation of the ethanol solutions containing ABT-963 and Pluronic, or by cooling the hot melt of the drug in the carrier. The dispersions were...

The objectives of this study were to investigate the effects of manufacturing parameters on the moisture sorption isotherms of some tablet formulations and to predict the moisture isotherms of the final formulations using polynomial equations. Three tablet formulations including a placebo and 2 drug products were prepared through wet granulation, d...

A novel mathematical model has been developed for predicting moisture uptake by packaged solid pharmaceutical products during storage. High density polyethylene (HDPE) bottles containing the tablet products of two new chemical entities and desiccants are investigated. Permeability of the bottles is determined at different temperatures using steady-...

A process for preparing a solid formulation of a lipid-regulating agent comprising forming a mixture of said lipid-regulating agent with a surfactant; granulating said mixture by melting, mixing, and congealing said mixture; and optionally forming a finished dosage form.

The maximum steady state flux of 171 compounds through PDMS membranes was predicted using a refinement of a previously developed empirical quantitative structure-transportability relationship (QSTR) produced using the reported flux data for 103 compounds. The model utilized partial atomic charge, solubility, and molecular weight as predictors. The...

The release of 10 substituted pyridines into water, loaded at their solubility limit in a silica-filled polydimethylsiloxane planar matrix, was studied using a quantitative structure-transportability relationship (QSTR) approach. Compounds contained seven different functional groups and a wide range of solubility in both water and the polymer matri...

A quantitative structure-transportability relationship (QSTR) for the prediction of flux of aromatic compounds through a polydimethylsiloxane (PDMS) membrane was developed using molecular modeling, A total of 103 compounds in 15 ring classes, including benzene, quinoline, naphthalene, pyridine, naphthyridine, furan, benzofuran, imidazole, benzimida...

The release of 52 compounds into water, loaded at their solubility limits in a filler-supported polydimethylsiloxane matrix, was studied using a quantitative structure-activity relationship (QSAR) approach. Half of the compounds studied were benzene derivatives and half were pyridine derivatives. Solubility of all the solid compounds in the matrix...