Effervescent Mixture Research Articles

Pharmaceutical Factors Affecting The Formulation Of Verapamil HCl Floating Capsules

Floating sustained release Verapamil HCl capsules were prepared using different polymers. Hydroxypropylmethyl cellulose 4000 and 50 (HPMC 4000 & HPMC 50), Carbopol 934, sodium alginate (Na alginate), carboxymethyl cellulose (CMC) and Pectin were used to study their effect on the release of Verapamil HCl from its capsules. Three different ratios of drug: polymer were adopted namely 1:1, 1:0.5 and 1:0.25 w/w. The effect of the weight of the prepared capsules on the dissolution rate of the drug using avicel to adjust the weight of the capsule to 300, 400 and 500 mg. The incorporation of effervescent mixture in the prepared capsules was tried to prepare floating dosage form with an in – situ gas generating mechanism for the seek of buoyancy improved drug release characteristics. Monobasic potassium citrate and potassium bicarbonate (1:1 w/w) as an effervescent mixture were used to generate CO2 gas. The effervescent mixture was mixed with the polymers in each capsule in 0, 1 and 2% w/w of the total weight of the formula. In-vitro release studies were performed to observe the effect of effervescence on the duration of drug release. It was observed that increasing the ratio of the polymer in the formula retard the drug release. The release profile gave a faster release rate in case of light weight capsule than heavy weight capsule. Increasing the amount of effervescent mixture per capsule retarded the rate of the drug release. Egyptian Journal of Biomedical Sciences Vol. 23 (1) 2007: pp. 244-256

Phase evaluation of an effervescent‐added apatitic calcium phosphate bone cement

Development of macroporosity during setting would allow fast bone ingrowth and good osteointegration of the implant. The interconnected macropores could be created in calcium phosphate cements (CPCs) through the addition of an effervescent porogen mixture to the component of the cements. But this addition could also affect other characteristics of CPCs, such as setting time, mechanical strength, extent of conversion of reactant to apatite phase, crystallinity, and chemical composition of apatite lattice. In this study, these properties were investigated in an effervescent-added calcium phosphate bone cement. From 0 to 20 wt % of an effervescent mixture was added to calcium phosphate cement (CPC) components and phase evaluations were performed after 24 h incubation at 37 degrees C and 28% relative humidity and 1, 3, 7, and 14 days immersion in a specific simulated body fluid. XRD and FTIR techniques were used to characterize the cement composition, crystallinity, and chemical groups in final CPCs. The results showed that addition of effervescent porogen affects the extent of conversion of reactant to apatite phase and crystallinity. In other words, using the effervescent porogen in CPCs could accelerate the rate of conversion of TTCP/DCPA reactant to apatite phase with smaller crystallites, so that it was the predominant phase (about 67%) after only 3 days soaking in SBF solution. The content of carbonate groups substituted for phosphate groups in apatite lattice increased when the effervescent additive was further added. The compressive strength of the set calcium phosphate cement decreased significantly with the addition of the effervescent agent and reached from 8 MPa for additive-free CPC to 1.3 MPa for 20% effervescent-added CPC. The compressive strength was improved after 3 days immersing of CPC in the simulated body fluid solution.

Magnetic marker monitoring of disintegrating capsules

Magnetic marker monitoring was studied for its applicability to investigate the in vivo fate and behavior of disintegrating magnetically marked dosage forms. As a model, hard gelatin capsules were filled with an effervescent mixture of lactose, ascorbic acid and sodium hydrogen carbonate containing 1.3 mg black iron oxide as a magnetic label. The accuracy of the localization procedure whilst calculating all parameters of the dipole in one fitting procedure was checked in phantom experiments where the capsules were moved in well-defined paths with respect to the measurement device. The calculated position coordinates of the capsules deviated between less than 2 mm up to 8 mm from the expected position values depending on the distance between the sensor area and the capsule’s path. Further experiments on the in vitro disintegration of the capsules showed that the value of the magnetic moment of the capsules can serve as a measure for their disintegration behavior. In vivo monitoring of the capsules was performed in eight experiments where a healthy volunteer swallowed each time one of the capsules. It was found that the in vivo disintegration behavior of the capsules corresponds well to their disintegration observed in water of about 37°C.

Gastric Mucosal Relief

RECENTLY, in this country, there has been a revival of interest in the demonstration of mucosal patterns in the stomach and duodenum, as an aid in establishing the normal and abnormal in gastric and duodenal diagnosis. This paper will attempt to demonstrate the possibility of a modification of the sedimentation method, by no means a new idea, but one which represents a slight departure from those used in the past. Historical Note As early as 1897, Raux and Balthgard, apparently independently and contemporaneously with Walter Cannon in this country, first used a bismuth opaque meal in demonstrating the motor phenomena of the stomach. Holzknecht and his group, in 1898, probably saw fluoroscopically the flow of bismuth opaque meals over the gastric rugæ. In 1906, they used a watery suspension of bismuth subnitrate in the preliminary part of the fluoroscopic study of the stomach (10 grams bismuth subnitrate in 50 grams of water, to which was added a tablespoonful of milk sugar). Palpation of the stomach in the erect posture made possible the visualization of the mucosal folds. After this procedure and while the stomach still contained the bismuth suspension, they distended the stomach by having the patient ingest an effervescent mixture of from four to five grams tartaric acid and from five to seven grams of sodium bicarbonate. This they followed by the usual opaque meal, four hundred grams of milk gruel with thirty-five grams of bismuth subnitrate. This examination is detailed because of its resemblance to our own procedure. With the advent of the Snook x-ray transformer, in 1907, and the distinct improvement in visualization due to “stopping” gastric peristalsis, further impetus was given to gastro-intestinal examinations by these methods. Cole, in 1909, demonstrated gastric rugæ by using the principle of sedimentation of bismuth subnitrate from a watery suspension as a special technic. His first films compare very favorably with the more modern methods of examination. Akerlund, in 1921, working with Forssell, whose classic monograph in 1913 laid the fundamentals of the anatomy and physiology of the stomach before the profession, applied the method of the “thin layer” to diagnosis of the duodenal bulb lesions by exerting external pressure to displace all but a thin layer of opaque medium from the bulb. Since then, innumerable observers have contributed both to the relief and thin layer methods, the majority, however, having tended to avoid the principle of sedimentation to demonstrate the rugal pattern. Pribram and Kleiber (1927), Hilpert (1928), and Vallebona (1926) revived the use of barium suspension and air distention. Small amounts of barium suspension were ingested and distributed by manual pressure, then the stomach was distended by air injected through a small tube (Pribram, Kleiber, and Hilpert), or by chemical means (Vallebona).