Formulation and characterization of chloramphenicol gelatin microspheres

Chloramphenicol loaded gelatin microspheres, as a specific oral drug delivery system, were prepared by two different methods. The effects of drug payload, and cross-linking with formaldehyde at different concentration levels on the size of microspheres and drug release from microspheres were studied. The results revealed that by increasing the drug payload, the diameter of microspheres was increased and also a faster drug release rate was obtained. However, the amounts of drug released were decreased. The kinetics of drug release from gelatin microspheres were found to conform with the Higuchi diffusion model. The results of in vivo studies in human volunteers showed that the peak urinary excretion of chloramphenicol gelatin microspheres occurred at 9 hours post-dosing and sustained over a period of 9 to 30 hours as compared with the control [7 hours]. So, the objectives of this study were achieved through improving both bioavailability of chloramphenicol. In addition, the frequency of administration and undesired systemic side effects were also reduced

Preparation and characterization of chloramphenicol starch microspheres

Soluble starch microspheres containing chloramphenicol were prepared by interfacial cross-linking technique using terephthaloyl chloride. The effects of various emulsification conditions such as initial drug loading, pH of the aqueous phase, speed of agitation and concentration of cross-linking agent on the characteristics of microspheres were investigated. For comparison, commercial Sephadex microspheres containing chloramphenicol were also prepared by lyophilization. The in vitro release studies indicated that soluble starch microspheres caused chloramphenicol release profiles to be sustained longer than those prepared with Sephadex. The degradation behavior, hydrophilic and bioadhesive properties of the formulated chloramphenicol microspheres were compared with gelatin and albumin microspheres previously prepared in the laboratories. Sephadex microspheres exhibited the highest hydrophilic property, while albumin microspheres showed the best bioadhesive behavior when compared with other tested microspheres. On the other h and, polysaccharides microspheres had a certain resistance to digested by pancreatin and pepsin enzymes solutions. The release kinetics of chloramphenicol from polysaccharides microspheres was found to conform with Higuchi model

Effect of some commercial antacids and tea drink on the in-vitro availability of frusemide

In this study, the dissolution rate of frusemide as a sparingly soluble diuretic, was determined in the presence of some commercial antacids. The effect of tea, as a conventional drink, on the in vitro availability of the drug in the presence of the selected antacids was also investigated. The obtained results revealed that, availability of frusemide was markedly affected in the presence of the selected antacids. The powdered antacids showed the most prominent effect, while antacid tablets produced the lowest in this respect. Also, a marked reduction in the dissolution rate of frusemide was observed in the presence of both tea and antacids. The observed reduction in the dissolution rate of frusemide with these antacids may be attributed to the chemical interaction, which was proved by IR, UV and TLC studies

Effect of some commercial antacids and tea drink on the bioavaiblilty of frusemide

The bioavailability of frusemide [FR] after oral administration of FR alone or FR with antacids or FR with antacids and tea drink was investigated using rabbits. The urinary excretion rate was monitored and drug concentrations were compared. The results revealed that the drug bioavailability was markedly reduced in the presence of the selected antacids, viz. Neogelco and Simeco suspensions, and Stomaclin powder. A significant reduction was recorded in both the total cumulative amount excreted over 24 h [P <0.05] and the excretion rate of the drug [P <0.01]. Tea drink was found to have an influence on FR absorption, if taken concurrently with the tested antacids. With Stomaclin powder, tea drink significantly [P <0.01] increased the biological availability of FR compared with that obtained with antacid alone, while such effect in case of Neogelco suspension was insignificant [P >0.05]. With Simeco suspension, however, tea drink significantly [P <0.01] reduced the biological availability of FR

Effect of aging on the physico-chemical stability of acetazolamide and phylpropanolamine hydrochloride tablets

The effect of ageing on the physicochemical stability of acetazolamide and phenylpropanolamine HCl tablets, directly compressed with Dynasan 114 and 118, was studied. Three temperature levels [25, 40 and 60C] at 75% relative humidity were adopted, either in closed or open containers over a 6-month storage period. The results revealed that the tablets stored in closed containers did not exhibit any significant changes in properties. However, tablets containing Dynasan 114 and stored at 60C were completely deformed after 4 months. All tablets stored at 75% relative humidity showed a significant increase in their weights and decrease in hardness values. The disintegration time and dissolution profiles [t 50%] of acetazolamide tablets containing Dynasan 114 or 118 were not affected by phenylpropanolamine HCl tablets, containing Dynasan 114 or 118, caused a decrease in their disintegration times and t 50%. The drug content and uniformity of weight of both drug content and uniformity of weight of both tablets were not affected in all formulations under the tested storage conditions

Formulation and evaluation of chloramphenicol albumin microspores in suppository form

Chloramphenicol albumin microspheres containing 25% dextrose as additive were prepared in the form of suppositories. Suppositories were formulated from Witepsol H15, Witepsol E75 and a blend of polyethylene glycols using the fusion method. The in vitro evaluation of chloramphenicol albumin microspheres revealed that microspheres prepared by emulsification method exhibited good results in terms of yield [>89.9%] and drug content [approximately 90%]. The suppositories made with Witepsol H15 showed the highest drug release as compared with the other tested bases. The mechanism of drug release profiles from suppositories containing Witepsol H15 or Witepsol E75 was found to conform the diffusion controlled system, while the suppositories made with polyethylene glycols followed first order release kinetics

Use of factorial design for the evaluation of the chemical stability of aspirin tablets

A factorial experimental design of type N = 2 3 was applied to predict the chemical stability of aspirin tablets directly compressed with sucrose-based vehicles [DiPac, Nu-Tab and Sugartab] and Avicel under 4 sets of storage conditions, 25% and 95% RH at two temperature levels [20C and 45C]. Tablets prepared by wet granulation technique were also employed for comparison. The quantitative factors were the temperature, relative humidity and time. The type of the vehicle used is only a qualitative factor. Tablets prepared with Avicel and those prepared by wet granulation technique gave complete measurable stability data under the selected storage conditions. The validity of the derived regression equations was verified by the experimental data of the classical design of experiments and the t50 values. Good agreement between the experimental and predicted data was obtained. Regression equations for the stability of tablets prepared with sucrose-based vehicles were not available due to their deformation under the selected storage conditions. The results of this investigation indicated that factorial design can have utility in predicting the chemical stability and expiry date of tablets in a short time and with less cost of experimentation

Effect of drug and drink combination on the pH profile of simulated gastric juice

The pH profile of simulated gastric juice [SGJ] in presence of commercial antacids with and without frusemide [FR] and/or drink was studied. All the tested antacids elevated the pH of SGJ with different degrees. Both FR and drinks, each alone, markedly reduced the effect of some tested antacids