Effect of aging on some physical properties of hydrochlorothiazide tablets

Plant-derived bioadhesives for wound dressing and drug delivery system

Synthetic polymers have been widely used in various biomedical applications like drug delivery, wound dressing, etc. They pose a question of bio-compatibility and bio-accumulation, limiting to a minimum class of synthetic polymers to be efficient and versatile. Hence, one cheap and reliant replacement is the use of natural adhesives over the synthetic adhesive polymeric system. The pluripotency of plant could be exploit, making it a perfect candidate for extraction of plant-derived adhesives component for wound dressing and drug delivery system in large-scale production. Current advancement use excipients which influence, the rate of drug release and absorption. Properties like matrix formation and environment responsive gelation can be exploited through these plant-derived components for controlled drug release according to specific therapeutic requirement. This review explores such plant-derived bioactive component: Mucilage and gums, their isolation, and characterization which can be exploited as excipients in the formulation of drug delivery system as well as a wound dressing.

Design and synthesis of new s-triazine polymers and their application as nanoparticulate drug delivery systems

The feasibility ofs-triazine polyamides to fabricate celecoxib-loaded nanoparticles.

Current perspectives on the dissolution stability of solid oral dosage forms

Dissolution stability (i.e., retention of the dissolution characteristics of a solid oral dosage form from the time of manufacture up to its expiration date) is a critical parameter from the standpoint of quality control, regulatory compliance, and impact on the bioavailability of the product. Significant changes in the in vitro release profiles of a drug product during storage may alter its bioavailability. Factors that affect the dissolution stability of a product during aging include formulation components (active drug, excipients, and coating materials), processing factors, storage conditions, and packaging. The role of each of these factors in promoting changes in dissolution in both immediate-release and modified-release products is dependent on the product and has to be evaluated on a case-by-case basis. Although data obtained under accelerated conditions of storage are not useful in predicting the dissolution shelf-life of the product under ambient conditions, they are of value in assessing the "ruggedness" of the product and its ability to withstand the varied climatic conditions during transport, shipping, and storage. The clinical significance of alterations in the in vitro dissolution profiles that may occur during aging and strategies to avert and counteract such changes are discussed in the article.

Methods for the assessment of the stability of tablet disintegrants

To allow assessment of the long-term stability of tablet disintegrants, two mechanisms for their functionality (i.e., water uptake and swelling force generation) were monitored. Three disintegrants, alginic acid, sodium starch glycolate, and crospovidone, were used to establish the methodology. The water uptake and swelling force methodologies developed were reproducible, thus allowing for the evaluation of the effect of time, temperature, and humidity on these properties of disintegrants. The data obtained suggest that the process of water uptake and swelling force generation was essentially a two-step process. Initially, water entered the pore space in the powder bed; there was a definitive lag time before a swelling force was generated. In the stability evaluation of alginic acid and sodium starch glycolate, samples were stored for 1-year. Above 30 degrees C and 75% relative humidity, the swelling force performance of alginic acid was markedly affected. Changes seen with sodium starch glycolate were much less marked.

Effect of binders on sulfamethoxazole tablets

Five batches of sulfamethoxazole tablets were prepared using different binders [starch, acacia, ethyl cellulose sodium carboxymethylcellulose, and povidone (1-vinyl-2-pyrolidinone polymer, PVP)] with water in 3% (dry basis) concentration. Comparative data show that granules prepared with PVP have the best flow properties and minimum angle of repose, percentage fines, and compressibility, while granules of sodium carboxymethylcellulose could not be compressed into well-defined tablets. Tablets containing starch as a binder possess all the quality features. Tablets from acacia, however, give a poor dissolution profile. Ethyl cellulose has less effective granule formation, leading to poor quality tablets. Rank correlation with respect to solubility and absorption characteristics according to granulating agent in the formation is: starch greater than ethyl cellulose greater than PVP greater than acacia.

Comparison of granule strength and tablet tensile strength

The granule strength (crushing load) of lactose granulated with 1-9% povidone was measured initially and at intervals during a 1-year period. The granule strengths of dibasic calcium phosphate dihydrate granulated with various concentrations of starch and povidone were measured. The axial and radial tensile strengths of tablets compressed from these granules were determined and related to concentration of binder and granule strength. The effect of compressional force on the integrity of granules in a tablet matrix is shown in scanning electron photomicrographs of the fractured tablets which had undergone a diametral compression test. It appears that the compressional force and the concentration of binder contribute more than granule strength to tablet tensile strength.

Conductivity and hardness changes in aged compacts

Batches of sodium, potassium, and ammonium chloride tablets containing no excipients and spray-dried lactose tablets containing 0.5% magnesium stearate were stored at 20 and 76% relative humidity. Electrical resistance and hardness measurements were made within 1 hr after compression and at intervals during a 45-day period. Hardness values of sodium, potassium, and ammonium chloride tablets stored at 20% relative humidity increased from 70 to 200% at 45 days, while conductances decreased 10-fold. Tablets stored at 76% relative humidity showed no increases or slight decreases in hardness with slight increases in conductance. Lactose tablets decreased slightly in hardness with corresponding increases in conductance.

The influence of polyvinylpyrrolidone on the solution and bioavailability of hydrochlorothiazide

The dissolution properties of hydrochlorothiazide-PVP 10 000 mechanical mix and coprecipitate systems were qualitatively similar to those previously reported using hydroflumethiazide. Quantitative differences were dependent on the proportion of PVP present, its molecular weight and method of incorporation. Cumulative urinary excretion data from test capsule preparations showed that bioavailability was enhanced by the presence of PVP. However, the degree of enhancement was less than that expected from constant surface area disc rate studies. Dissolution tests on the capsule formulations, using the U.S.P. basket stirrer assembly, did not correlate with in vivo results. Using the Levy beaker method and a stirring speed of 40 rev min-1, good correlation between amount dissolved in 30 min and amount excreted in urine after 24 h was obtained. The dissolution tests revealed that PVP retards the initial dissolution from capsule dosage forms, probably by retarding deaggregation and dispersion of drug particles.

Effect of aging on physical properties of phenylbutazone tablets

A study was made of the influence of age on the physical properties of phenylbutazone tablets BP, with special reference to in vitro dissolution rates. Past batches of tablets showed a progressive decrease in dissolution rate with age. This effect could be simulated in short periods by using elevated temperatures. The effect appears to be connected with the subcoat layer of the sugar coating of the tablet which adheres more strongly to the tablet core and slows down its disintegration.