In-vitro availability of erythromycin from some commercial tablets

The in vitro characteristics of nine batches of film-coated erythromycin stearate tablet br and s marketed in Egypt and one batch of enteric-coated erythromycin base tablets were examined. The disintegration times and dissolution rates of erythromycin stearate tablets indicated wide interbr and and inter-batch variability as well as intertablet variability in some batches of br and B tablets. Enteric-coated tablets showed excellent in vitro properties. The results strongly pointed to formulation and coating problems in addition to variations in the intrinsic dissolution properties of erythromycin stearate raw material, as potential causes of the relatively poor in vitro performance of erythromycin stearate tablets. The correlation obtained between dissolution data of the tablet products under study and the bioavailability parameters of the same products reported earlier, indicated the usefulness of simple in vitro tests for the continued monitoring of the production and bioavailability of erythromycin tablets

Development of fast release mebeverine hydrochloride tablets

The drug release from five commercial br and s of mebeverine hydrochloride tablets was tested. The results revealed the presence of large interbr and and intrabatch differences. These differences in drug release were attributed mainly to the physical behavior of the raw material during the production processes. Mebeverine hydrochloride crystals prepared from benzene were used for the preparation of four tablet formulations by the direct compression technique. The release of the drug from formulated tablets was superior to most of the commercially available br and s

Comparative bioavailability study of theophylline in suppositories relative to oral capsules and prolonged release tablets

A comparative bioavailability testing was carried out on theophylline [TH] suppositories [200 mg] in a hard fatty base and aminophylline [AM] suppositories [250 mg] in a polyethylene glycol [PEG] blend. The study was performed on 6 male healthy volunteers in a cross-over fashion. Theophylline saliva concentration data were compared with those obtained for aminophylline oral capsules [250 mg] and prolonged release [PR] [200 mg] theophylline tablets [Quibron SR]. The results showed that bioavailability of TH from hard fat and PEG suppositories, and from PR tablets were 71%, 76%, and 57%, relative to the oral capsules AUC 0-12, respectively. Other pharmacokinetic parameters, such as T max and MRT were highest for PR tablets [4.16 and 19.07 h, respectively] and lowest for AM capsules [1.08 and 9.49 h, respectively]. The two suppository formulations had intermediate values

Development of stable theophylline suppositories

Nine theophylline and seven aminophylline suppository formulations were prepared. The base used were polyethylene glycol blend, Suppocire A, NA10 and AP, Witepsol H15 and Estaram H15. The fatty bases were used either alone or in combination with each other. In some theophylline formulations, 1% docusate sodium, as a release enhancer, was incorporated. The effect of some additives on the stability of aminophylline suppositories was investigated. All formulations were tested for their drug release and melting points over a period of one year. The results revealed that formulations prepared with aminophylline in PEG, theophylline in PEG or Suppocire AP possess the best stability and fastest drug release. Besides, these formulations were recommended for the development of theophylline suppositories

Formulation and in-vitro/in vivo evaluation of metronidazole suppositories

The optimization of metronidazole suppositories has been investigated. 12 different formulations were prepared using 7 fatty bases; namely, Suppocire A, NA 10, AP and BP, Witepsol H15, Estaram H12 and Estaram H15, either alone, in a mixture, or in combination with other excipients such as docusate sodium or Tween. The different formulations were evaluated by the in vitro drug release rate using the non-membrane method, in the BP 88 dissolution apparatus. The release pattern of the drug from formulations containing only the bases showed large differences. The percent drug released after 15 minutes ranged from 6 [in case of Suppocire A] to 100% [in case of Suppocire AP and BP]. The presence of docusate sodium and Tween 80 in formulations prepared with Suppocire A and NA 10 enhanced the metronidazole release. The effect of ageing on drug release from some selected formulations was also studied. The suppository formulation containing only the drug in Suppocire AP was tested in vivo on 8 healthy male volunteers in comparison to the commercial st and ard tablets [Flagyl]. The obtained bioavailability and pharmacokinetic data for both products were nearly similar

Evaluation of some lipophilic materials as release controlling fillers for the development of ibuprofen formulations

Three fatty materials [Compritol 888, Precirol AT05 and Precirol wL-2155] were used for the preparation of prolonged release ibuprofen granules, tablets and capsules. The drug release from the different formulation was studied using USP XXII dissolution apparatus type 2. The release mechanisms of the drug from the different formulations were also elucidated. The 3 tested polymers seemed suitable as release controlling fillers for the development of ibuprofen formulations. Tablet preparations were superior to granule and capsule formulations

Development of prolonged release ketoprofen tablets

Prolonged release ketoprofen tablet formulations were prepared by the fusion method using different concentrations of hydrogenated castor oil or a mixture of hydrogenated castor oil and polyethylene glycol 6000. The release of the prepared formulations, in comparison with a st and ard ketoprofen sustained release capsule, was performed on USP XXII dissolution apparatus type 2. The dissolution medium was 0.1N HCl and rotated at 100 rpm. The pH of the dissolution medium was changed after one hour to a pH 7.4. The release study revealed that only 4 mg of hydrogenated castor oil produced tablets with a release pattern similar to that of the st and ard capsule. The drug release mechanism from all formulations was calculated and found in most cases to be of Fickian's diffusion type

Effect of sucralfate on the in-vitro availability of some drugs

This work studied the effect of sucralfate on the in vitro release of some drugs which may influence their in vivo availability. Eight products including five conventional tablets [metformin, ketoprofen, norfloxacin, mebeverine and ranitidine] and three prolonged release tablets [metformin- R, theophylline SR and diltiazem] were chosen. In most of the cases, the presence of sucralfate decreased the drug release from their dosage forms. The influence of sucralfate on the in vitro drug release was ranked as follows: Ketoprofen > mebeverine > ranitidine > norfloxacin > metformin for conventional tablets and diltiazem > theophylline SR > metformin-R for controlled release tablets