Modified Release Delivery Systems Research Articles

Recent Patents on Modified Release Oral Dosage Forms

Background: Conventional oral dosage forms have limited bioavailability and frequent dosing of the drug is needed to maintain the effective therapeutic concentration in the body. This results in poor patient compliance and fluctuations in the plasma drug levels, especially in the chronic diseases and disorders.
 Objective: To overcome such problems and to enhance the efficiency and bioavailability of the drug, modified drug delivery systems such as extended release delivery systems (controlled release; sustained release) and delayed release delivery systems are developed which can prolong the release and hence action of the drug in the body.
 Methods: Through this review, we throw the light on recent patents and patent applications on modified release systems pertaining to oral dosage forms. The various free patent search databases were used to collect and analyze the information on modified release delivery systems.
 Results: Modified release systems such as extended release and delayed release delivery systems have been found to be of great significance due to their advantages over immediate release dosage forms. These systems are formulated using various approaches, different types of release controlling polymers such as natural, semisynthetic and synthetic polymers and found to avoid the limitations of conventional oral dosage forms.
 Conclusion: Modified drug release systems have potential especially, in case of the chronic diseases, mental health disorders and lifestyle diseases and disorders. These systems have unique commercial advantages which will sustain the interest of both the researchers and the pharmaceutical companies.
 Keywords: Modified release systems, extended release systems, controlled release systems, sustained release systems, delayed release systems, oral dosage forms, multilayer dosage form, multilayered tablets

Engineering Size and Structure of Particles in Novel Modified-Release Delivery Systems.

Particle engineering has become a hot topic in the field of modified-release delivery systems during last decades. It has a wide range of pharmaceutical applications and is a bridge linking between drugs and drug delivery systems. Particles are an important part of many dosage forms and viewed as a carrier of drugs. Their size, shape, crystalline form, and structure directly affect the stability and releasing pattern of drugs. Engineering size or modifying particles by forming porous, core-shell, or skeleton structures can realize the development and utilization of functionally modified release systems (including fast-release systems, sustained-release systems, and targeted-release systems). However, there are certain problems in the practical application, such as bitter taste and coating damage. Combining with some polymer or lipid materials to form core-shell or embedded structures is considered as the key to taste masking. And, using cushioning agents is proven to be effective in preserving the integrity of the functional coating film of multiparticulates during tableting. To sum up, this review, from a particle engineering point, expounds the influence of different factors on the functionality of particles and offers some useful comments and suggestions for industry personnel.

Dissolution of Extemporaneous Paracetamol Capsules

Aim: To investigate the dissolution characteristics of extemporaneously prepared capsules containing hypromellose and paracetamol tablets.Method: Capsules of varying sizes containing paracetamol (powdered tablets) with varying amounts of hypromellose (4–20% w/w) were extemporaneously prepared. Dissolution was investigated using a USP dissolution testing apparatus. Paracetamol dissolution was quantitated using UV absorption spectrophotometry. The impact of hypromellose content, tablet excipients, capsule size, content weight and mixing methods were investigated.Results: Over a 4‐hour period, paracetamol dissolution decreased with increasing hypromellose content. Paracetamol dissolution was 100% from capsules containing 4% hypromellose and 52 ± 3% from capsules containing 20% hypromellose. Reformulated tablets with different formulations resulted in different dissolution rates. The dissolution rate was faster from small capsules and slower from capsules with a lower content weight. The method used to mix the powders also had a significant effect on the dissolution rate.Conclusion: Modified‐release delivery systems can be extemporaneously prepared from reformulated tablets using hypromellose. Hypromellose content, tablet excipients, capsule size, content weight and mixing methods have an impact on the dissolution rate.J Pharm Pract Res 2004; 34: 276–81.

Biopharmaceutical characterization of topical liposome formulations bearing 5-fluorouracil

Liposome dispersions and liposome gel formulations for topical administration were evaluated as modified release delivery systems for 5-fluorouracil. Drug substance has been entrapped in the internal aqueous compartment of liposomes during the preparation. The concentration of 5-fluorouracil in the hydration medium was varied and the effect on the liposome characteristics was considered. Liposome gel formulations were prepared by incorporation of liophylized liposomes into a structured vehicle of chitosan. The decrease of the amount of aqueous phase bearing total drug quantity (drug/aqueous phase ratio from 1:100, 1:60, 1:40) led to an increase of the percentage of liposome-entrapped drug, and decreased percentage of drug release, while particle size analysis showed no changes in vesicle size. Liposome gel formulations showed initially a higher drug release rate in comparision with liposome dispersions, which could be related to the release of “free” 5-fluorouracil, leaked from liposomes due to the process of liophylization. This was followed by slower release (after 1.5 hour) as a result of the influence of the viscosity of the gel matrix.

In Vitro Evaluation of Drug Release from Modified Release Delivery Systems: Initial Experiences with Calibrators for USP Dissolution Apparatus 3.

In Vitro Evaluation of Drug Release from Modified Release Delivery Systems: Initial Experiences with Calibrators for USP Dissolution Apparatus 3.