Influence of gelucires and rhodopases on sustainment of in -domethacin via solid dispersions

Solid dispersions of indomethacin in different release retarding materials; namely, Gelucire 50/02 and Gelucire 50/13, Rhodopas M and Rhodopas H were prepared by fusion and coprecipitation methods, respectively. Solid dispersions were compressed into tablets where both physical parameters and dissolution were studied. The effect of various release retardants on anti-inflammatory characteristic of indomethacin adopting rat paw edema and ulcerogenicity on rat stomach from the most appropriate preparations reached were done. A satisfactory prolongation of drug dissolution from its tablets made with Gelucires was obtained from drug tablets containing 10% w/w of Gelucire 50/02. However, drug tablets prepared with 2.5% of the same polymer showed a shorter retardation time. The percentage of drug release was decreased by increasing the percentage of Gelucire 50/02. In contrast, the increasing Gelucire 50/13 concentration caused a remarkable increase in drug release from its tablets. On the other h and, indomethacin tablets prepared with Rhodopases M and H showed a remarkable protraction of the drug release. The greatest protraction was obtained with 6% Rhodopas H that was too excessive to attain a reasonable level

Microencapsulation of indomethacin using different polymers

Indomethacin microcapsules were prepared with three different polymers; namely, ethyl cellulose 100[EC], Eudragit RSPM [Eud] and sodium carboxymethylcellulose [Na CMC] using solvent-evaporation technique with the first two polymers and coacervation-phase separation by electrolyte addition technique with the latter. Kollidon K-25 was used as a channeling agent. All the prepared microcapsules were subjected to drug content determination, microscopical examination, particle size analysis and drug release studies. The anti- inflammatory characteristic adopting rat paw edema method and ulcerogenicity in terms of ulcer index on rat stomach of indomethacin from the most appropriate preparation reached were studied

Preparation and pharmacokinetic evaluation of carbamazepine controlled release solid dispersion granules

Solvent evaporation technique was applied to prepare granules of carbamazepine coprecipitates using Eudragit RLPM, Eudragit RS 100, Cellulose acetate phthalate and Ethyl cellulose in 1: 1 and 1:2 drug: polymer w/w. In vitro release of carbamazepine from its coprecipitates with the previously mentioned polymers as well as the commercially available tablets [Tegretol CR200 tablets, Ciba] was carried out in gradient pH media [1.2, 2.5, 4.5, 7, 7.4] for 7 hours. The data were kinetically treated. Pharmacokinetic studies of the selected formula made with ethyl cellulose [1:1] and Tegretol CR 200 mg tablets [Ciba], as a reference standard, as well as carbamazepine powder were done using albino rabbits. Carbamazepine plasma level was determined using HPLC. The in vitro and in vivo data revealed that the suggested formula and the innovator's product exhibit% dissolution, tmax, Cpmax, AUC and /delta[1/2] as follows, 58.4%, 8 hr, 24.15 +/- 5.5/-microg/ml, 277.24hr microg/ml, 5.6hr and 64.22%, 8hr, 28.93 +/- 315.14 microg/ml, 313.6 hr, microg/ml, 5.2 hr respectively. It is worthy to note that the suggested formula showed a more prolonged duration of action

Influence of certain stabilizers on physical stability and rheology of allopurinol suspension

Identification of surface charge of allopurinol powder was established by promotion of flocculation of drug suspension with positively charged electrolyte viz., aluminum chloride and negatively charged one viz., potassium dihydrogen phosphate where the drug was proven to be positively charged. Wettability of allopurinol powder was tested with certain non-ionic surfactants and polyols via packed drug column technique where 15% of sorbitol was optimum for the purpose. Stabilization of allopurinol suspension in a deflocculated manner was done with certain finely dispersed solids where 5% of aerosil 200 and 1% of veegum HV produced products with pouring, redispersing and physical stability properties over 3 months associated with pseudoplastic, thixotropic flow characteristics. Other tested stabilizers of natural, synthetic or water-soluble cellulose derivatives yielded deflocculated drug suspensions which were not as good as aerosil 200 and veegum HV relevant to stability and rheology. Flocculated drug suspensions stabilized with either 8% of aerosil 200 or 0.1% of carbopol 940 were sufficiently pourable, redispersed, physically stable over 3 months and associated with pseudoplastic, thixotropic flow with the first agent and pseudoplastic flow pattern with the second

Buccal benzydamine hydrochloride bioadhesive device

Aiming to have an extended anti-inflammatory activity for buccal and pharyngeal inflammations, a bioadhesive benzydamine hydrochloride [BH] dosage form was formulated. Fourteen formulae were layed down with different variables in the lower, middle and upper layers. The prepared products were subjected to score system for product acceptability, in vitro release and in vivo studies. The results obtained showed that the lower layer with optimum characteristics was composed of a mixture of hydroxypropylcellulose [HPC]: carbopol 934 [CP] in a ratio of 2:1. Middle layer of optimal barrier effect consisted of magnesium stearate [MS]. Upper layer [drug reservoir layer] contained benzydamine hydrochloride: hydroxypropylcellulose: carbopol 934 in a ratio of 3:4:2. The product proved to provide first drug flush equivalent to that of a commercial drug mouth wash. The drug release rate from the product was found to be optimal both in vitro and is vivo, is addition to a reasonable acceptability score

Complexation of khellin with different cyclodextrins

Inclusion complexation of khellin and beta cyclodextrin [beta CD], gamma cyclodextrin [gamma CD] and hydroxypropyl beta cyclodextrin [HP beta CD] in water and in solid state were studied by the solubility method, UV spectrophotometry, differential scanning calorimetry [DSC], X-ray diffractometry, IR-spectroscopy and dissolution study. Solubility of khellin in water increased with the addition of cyclodextrins. The complex system formed had 1: 1 stoichiometric ratio with beta, gamma and HP beta CD. The apparent 1: 1 stability constant of khellin complexes with beta, gamma and HPBCD were 27.71 M-1, 66.67 M-1, 32.46 M-1 respectively. Phase solubility studies revealed 14, 24 and 35 fold increase in the solubility of khellin in the presence of cyclodextrins. More evidence of complex formation was obtained from the analysis of UV, IR, DSC and X-ray diffraction studies. The dissolution rate of khellin was significantly enhanced by complexation with cyclodextrins