Biopharmaceutical evaluation of time-controlled press-coated tablets containing polymers to adjust drug release

Abstract

This paper deals with press-coated modified release tablets in which the drug dose is situated in the core or is divided between the core and the coat. The coat contains polymer (sodium alginate or hydroxypropylmethyl cellulose, HPMC) to control drug release. The main objective was to investigate how the pharmacokinetic profile of the model drug could be modified by altering the proportion of the drug between the core and the coat. The effect of the amount of the polymer in the coat was also studied. Bioavailability tests were carried out on healthy volunteers. In the absorption curves of the tablets containing 50%, 67% and 80% of the drug in the core and 180 mg HPMC in the coat a bimodal profile was observed. No bimodal release pattern in the in vitro dissolution studies was found. If the whole dose was incorporated in the core the absorption curve has only one clear t(max) value at about 10 h. Doubling the amount of HPMC in the coat dramatically decreased drug absorption. It was concluded that, if a slightly reduced t(max)-value was required, the viscosity grade of HPMC used should be lowered.

Chronotherapeutics and Chronotherapeutic Drug Delivery Systems

“…The outer barrier, which controls drug release, can be either swellable or erodible. Lag times can be varied by changing the barrier formulation or the coating thickness [7,8]. Matsuo et al have developed a diltiazem hydrochloride formulation intended for use in the treatment of time-related symptoms of ischaemic heart disease and hypertension [37].…”

“…Therefore, variation in disease state and drug plasma concentration need to be taken into consideration in the development of drug delivery systems intended for the treatment of diseases with adequate dose at the appropriate time. The term, 'Chronopharmaceutic drug delivery system', is used to describe a kind of drug formulation which can cause circadian variation in drug plasma levels [6][7][8].…”

Influence of excipients, drugs, and osmotic agent in the inner core on the time‐controlled disintegration of compression‐coated ethylcellulose tablets

“…In particular, the direct-compression method may be used to replace the complicated coating processes of conventional barrier coating to prepare the compression-coated tablet. [4][5][6][7] This manufacturing method not only can eliminate the time-consuming and complicated operation processes but also improves the stability of drug by preventing it from environmental moisture. The compression-coated tablet containing an inner core and an outer coating shell is not only rate-controlled but also time-controlled to deliver the drug when required.…”

Different approaches of katira gum formulations for colon targeting

“…Colon drug delivery has been more utilized in treatment of diseases like nocturnal asthma, angina and rheumatoid arthritis. Polysaccharides such as amylose, guar gum, pectin, chitosan, inulin, cyclodextrins, chondroitin sulphate, dextrans, dextrin and locust bean gum have been investigated for their use in colon targeted drug delivery systems [4,5]. Mechanism sorted by earlier researchers for targeted colon drug delivery are pH-and time-dependent systems, pressure-controlled release systems, osmotic systems, prodrugs and polysaccharidebased delivery systems [6][7][8][9].…”