Muscle Tissue as a Surrogate for In Vitro Drug Release Testing of Parenteral Depot Microspheres.

Despite the importance of drug release testing of parenteral depot formulations, the current in vitro methods still require ameliorations in biorelevance. We have investigated here the use of muscle tissue components to better mimic the intramuscular administration. For convenient handling, muscle tissue was used in form of a freeze-dried powder, and a reproducible process of incorporation of tested microspheres to an assembly of muscle tissue of standardized dimensions was successfully developed.

In-vitro drug release testing of parenteral formulations via an agarose gel envelope to closer mimic tissue firmness.

Current in vitro drug-release testing of the sustained-release parenterals represents the in vivo situation insufficiently. In this work, a thin agarose hydrogel layer surrounding the tested dosage form was proposed to mimic the tissue. The method was applied on implantable formulations of different geometries (films, microspheres, and cylindrical implants); prepared from various polymers (several Resomer® grades or ethyl cellulose) and loaded with different model drugs: flurbiprofen, lidocaine or risperidone.

Silk Fibroin as a Novel Alcohol-Resistant Excipient for Sustained-Release Tablet Formulation.

Concomitant intake of alcoholic beverages with sustained-release oral formulations may potentially lead to dose dumping. Alcohol-resistance testing is currently a requirement for the manufacturers by regulatory authorities. Silk fibroin produced by silkworm Bombyx mori is suggested in this work as a potential alternative to a narrow spectrum of alcohol-resistant excipients.

Nanoparticulates with drug release based on temperature change.

Unlabelled: The stimuli-induced release systems are able to respond to an external stimulus resulting in drug release in a controlled pattern. The origin of the external stimuli may be of physical, chemical or biological nature. Thermo-responsive delivery systems respond to the change in temperature and they were mainly designed in order to be used in the cancer treatment method using elevated temperature, i.

Optimization of diclofenac sodium profile from halloysite nanotubules.

Halloysite, aluminosilicate clay with the particle shape of multilayered hollow nanotubes, used in various non-medical applications, e.g. in ceramic industry, was discovered for pharmaceutical purposes in recent years.

Diclofenac sodium entrapment and release from halloysite nanotubules.

Unlabelled: Halloysite was found to have interesting nanotubular geometry viable for the entrapment of various active agents. In this experiment, the ability of hollow halloysite cylinders to entrap the anionic model drug diclofenac sodium and to retard drug dissolution rate was investigated. Drugs could be incorporated into layered tubules via three different mechanisms: adsorption, intercalation and tubular entrapment.

Halloysite - interesting nanotubular carrier for drugs.

Halloysite is a naturally occurring mineral similar to kaolin, possessing a special particle shape in the form of ultramicroscopic multi-layered hollow cylinders. It is utilizable in many industrial branches and due to its advantages, e.g.

Hot-melt extrusion.

Hot-melt extrusion (HME), originally coming from plastic industry, becomes at present an interesting technology also in the pharmaceutical field. The number of drugs with poor solubility and also bioavailability is increasing. In addition, most of the organic drugs are exhibiting polymorphism.

The development of Eudragit® NM-based controlled-release matrix tablets.

Unlabelled: Eudragit® NM was investigated as a matrix former in combination with microcrystalline cellulose as an insoluble filler for preparing controlled-release tablets containing model drugs with different solubility.

Material And Methods: Three sets of matrix tablets differing in the drug-to-filler ratio (1:1, 2:1, and 4:1) and polymer amount with diltiazem hydrochloride (freely soluble) or caffeine (sparingly soluble) were prepared. Samples were evaluated by the dissolution test at pH 6.

Stability testing of alginate-chitosan films.

Pellets containing rutin prepared by the extrusion/spheronization method were coated with sodium alginate-chitosan film. Important quality parameters in the pellets before coating were determined, and after coating the dissolution profiles of the drug were evaluated in dissolution media of the pH corresponding to the conditions in the gastrointestinal tract. Samples of coated pellets were located in the boxes for stability testing under different conditions, i.

Bioadhesive pellets increase local 5-aminosalicylic acid concentration in experimental colitis.

Topical delivery of 5-aminosalicylic acid (5-ASA) to the colonic mucosa is important in order to achieve effective drug concentration in the site of inflammation and to minimize its systemic availability. 5-ASA loaded pellets were prepared by an extrusion/spheronization method. Mucoadhesive biopolymer chitosan was incorporated into the pellets, and drug delivery to the colon was controlled by the pH-sensitive polymer Eudragit® FS.

Coated chitosan pellets containing rutin intended for the treatment of inflammatory bowel disease: in vitro characteristics and in vivo evaluation.

Preparation of coated pellets intended for rutin colon delivery, their evaluation in vitro and in vivo in experimental colitis in rats was the purpose of this study. Pellets were obtained using extrusion/spheronization and coated with three types of coatings (caffeic acid/hypromellose/alginic acid; sodium alginate/hypromellose/zinc acetate; sodium alginate/chitosan). Dissolution using buffers of pH values, β-glucosidase and times corresponding to gastrointestinal tract (GIT) was provided.

Oxycellulose beads with drug exhibiting pH-dependent solubility.

The aim of this study was to develop novel hydrogel-based beads and characterize their potential to deliver and release a drug exhibiting pH-dependent solubility into distal parts of gastrointestinal (GI) tract. Oxycellulose beads containing diclofenac sodium as a model drug were prepared by the ionotropic external gelation technique using calcium chloride solution as the cross-linking medium. Resulting beads were characterized in terms of particle shape and size, encapsulation efficacy, swelling ability and in vitro drug release.

[Pelletization of melts and liquids].

During the second half of the last century, pelletization methods based on wetting were developed, e.g. agglomeration in coating pans, pelletization plates or fluid-bed equipment, layering of the drug in solution or suspension on inactive spherical cores, extrusion/spheronization and later on also rotoagglomeration in rotogranulators or rotoprocessors.

Coated hard capsules as the pH-dependent drug transport systems to ileo-colonic compartment.

Purpose: The aim of this study was to investigate the suitability of hard capsules of different composition (gelatin-G, gelatin coated with hydroxypropyl cellulose-G/HPC, and hypromellose-H) for a coating with aqueous dispersion of pH-dependent synthetic polymer Eudragit(®) FS (E(FS)) and to evaluate in vitro the coated capsules as transport systems for ileo-colonic drug delivery.

Methods: Three sets of hard capsules with increasing coating levels (5-30%) were obtained by Wurster technique. The release of model drug (caffeine) from prepared samples was tested using paddle dissolution method with continual pH change (pH 1.

Multiparticulate systems containing 5-aminosalicylic acid for the treatment of inflammatory bowel disease.

Background: In recent years, many achievements have been realized in the therapy of inflammatory bowel disease (IBD) although its etiology remains unknown. Thus IBD treatment is symptomatic and targets general inflammatory mechanisms. Oral formulations containing 5-aminosalicylic acid (5-ASA) have become the standard therapy for mild-to-moderate IBD.

Oxycellulose as mucoadhesive polymer in buccal tablets.

Background: Oxycellulose (OC) is biodegradable and bioabsorbable cellulose derivative used in medicine to support hemostasis and tissue healing. Recently, its antimicrobial and immunomodulating properties, as well as its potential in modern therapeutic systems as release modifying excipient, drug carrier, and/or mucoadhesive polymer, are widely discussed.

Method: To study its last-mentioned characteristics, directly compressed tablets containing 5 mg of cetylpyridinium chloride (CPC) as a model drug and 90 mg of mucoadhesive polymer [oxycellulose sodium (NaOC) alone or in a combination with one of five widely used mucoadhesive polymers] were prepared to ensure 8 hours prolonged release of CPC.

Coated capsules for drug targeting to proximal and distal part of human intestine.

Coated hard capsules are becoming increasingly important for a number of reasons such as administration of new active ingredients, oral vaccination, colon drug delivery or their use in preclinical and clinical trials. The independency of coating composition on capsules filling is the major advantage of this dosage form. In our study, two types of hard capsules (gelatin and hypromellose) were coated by non-aqueous solutions of Eudragit L and S 12.

Pellets for oral administration of low-molecular-weight heparin.

Background: Oral absorption of low-molecular-weight heparin (LMWH) is limited by its molecular size and negative charge. It has been shown previously that orally administered polymeric nano- or microparticles containing encapsulated LMWH have led to gastrointestinal absorption of heparin in rabbits.

Method: Based on these investigations, pellets containing two LMWHs, enoxaparin (MW 4500 Da) or bemiparin (MW 3600 Da), and EudragitRS30D (ERS), were prepared using extrusion/ spheronization technique.

Soluble filler as a dissolution profile modulator for slightly soluble drugs in matrix tablets.

The purpose of this experimental work was the development of hydrophilic-lipophilic matrix tablets for controlled release of slightly soluble drug represented here by diclofenac sodium (DS). Drug dissolution profile optimization provided by soluble filler was studied. Matrix tablets were based on cetyl alcohol as the lipophilic carrier, povidone as the gel-forming agent, and common soluble filler, that is lactose or sucrose of different particle size.

Pellet starters in layering technique using concentrated drug solution.

Characteristics of inert starters in drug solution layering are important for successful active pellet formation. Four types of starters composed of sucrose or microcrystalline cellulose (MCC) or lactose and MCC were compared in our study. The active pellets were prepared using Wurster type apparatus.

Differences in characteristics of pellets prepared by different pelletization methods.

Pellets are currently a very popular dosage form for oral application. They can be prepared by several pelletization techniques. Extrusion/spheronization, commonly used in the pharmaceutical industry, and modern agglomeration in a rotoprocessor were the methods chosen for pellet preparation in our study.

Comparison in vitro felodipine release rate from the original versus generic product with controlled release of the drug.

After patent protection of original brand is over, there are a lot of generic products occurring on the pharmaceutical market. It may be the way to reduce the price, but on the other hand, one should expect the same quality and almost identity with original brand, because the development of generic drugs is based on pharmacological properties of the original brand. The aim of this study was to compare the similarity of two products with controlled release of felodipine--generic product Presid and original brand Plendil--which are commercially available in Czech Republic, based on in vitro dissolution testing.