In vitro release study of nystatin from chitosan buccal gel

Bioadhesive nystatin gel formulations with chitosan as gelling agent were developed and evaluated for in vitro release properties and antifungal activity. Different concentrations of nystatin [1,2 and 3% w/w], chitosan [5, 6 and 7% w/w] and various solubilizing agents [glycerol, Polyethylene glycol 400, Sodium lauryl sulphate, Tween 20, Tween 60 and Propylene glycol[wre used to prepare the gels. The best release profile of nystatin was obtained with 2% w/w nystatin, 5% w/w chitosan and 10% w/w propylene glycol and it occurs through fickian diffusion mechanisms. The effect of preparation method was also evaluated and it was found that a significant increment in nystatin release from the selected formula was obtained with 3% acetic acid. The viscosity of the prepared gels increases significantly with increasing chitosan concentration [p<0.05] and incorporation of nystatin into the gel has no significant effect on viscosity. In vitro microbiological study for antifungal activity of the selected formula was performed and compared with the commercially available nystatin suspension; results indicated that chitosan significantly enhanced the antifungal activity of nystatin against Candida albicans

Formulations and in vitro evaluations of an effervescent dosage form for diazepam, pyridoxine hydrochloride, dimenhydrinate, and ibuprofen

Different dosage forms for a certain drug could be considerably affected its bioavailability and consequently its pharmacological effect. Effervescent tablets were prepared For diazepam [2,5,10 mg], pyridoxine HCL [50 mg],. dimenhydrinate [50 mg], and ibuprofen [200 mg]. For the first three drugs, an effervescent base which was composed from sodium bicarbonate; tartaric acid; and citric acid in a a ratio of 3.44: 2:1, respectively, was used. On the other hand, a ratio of 5.44: 0.5: 0.5 was used for ibuprofen. For all formulations 1.5% polyethylene glycol [PEG 6000] was used as a lubricant. The resulted effervescent tablets were evaluated physically and chemically. The results showed that hardness of these tablets was in the range of 3.5- 5.6 kg with a friability of less than 1%. At the same time, disintegration time for these talets was 1.8 - 3.0 mins. and the pH of the resulted solutions was in a range of 5.15- 7.24. The stability of the prepared effervescent tablets was also studied at 40C, 50C, and 60C for eight weeks. The calculated expiration date [t 10%] for diazepam, pyridoxine HC1, dimenhydrinate, and ibuprofen was about 2.32,2.1, 2.2, and 2.38 years, respectively. The data of this study encourage the formulation of effervescent tablet for above drugs which might affect the patient compliance and absorption of these drugs

Formulation of metformin HCL as a sustained release tablets

Sustained release tablets are pharmaceutical dosage form comprising a wide range of pharmaceutical products. Metformin HCL is an oral hypoglycemic agent which is prescribed as drug of choice of biguanide class. Many trials were made to formulate this drug in a sustained release dosage form. by employing dispersion [fusion method] with various retardants [Beeswax, Carnauba wax stearic acid] and the channeling agent polyethylene glycol [PEG]. It was found that the most satisfactory tablets could be obtained by incorporating a mixture of carnauba wax stearic acid and PEG 4000 as coated material. Also faster release was obtained when smaller coated granules were used. On the other hand, a comparative study of the physical properties of the prepared formula and glucophage. Retard [R] tablets showed that both products were more or less similar

Formulation of potassium chloride as a sustained release oral solid dosage form I

Many trials were made to prepare a satisfactory formula for potassium chloride as a sustained release tablet dosage form by employing various retardants [carnauba wax, stearic acid and bees wax] using fusion method for dispersion. It was found that the release of drug is affected by the concentration of total wax contents, by the type of waxy material, and by the ratio of one type of wax to the other when a combination of two waxes were used. The best formula was obtained from combination of carnauba wax and stearic acid as a 20% total wax contents of the tablet weight in a ratio of 1:1. In addition, acrylic resin Eudragit[TM] Ll00 and Eudragit[TM] RS PM were used as a film coating material. More satisfactory results were obtained by coating the tablet for 5 times with Eudragit[TM] Ll00 which has an enteric property. Comparing the dissolution of the prepared tablets with KCL- retard Zyma[R] tablets showed that, the release of drug from the selected formula was more or less similar to that obtained from KCL- retard Zyma[R] tablets at pH 7.6 and 37C. The dissolution rate constants were: K1: 0.5 meq. min-1/2, K2: 0.27 meq. min-1/2 and K1: 0.52 meq. min-1/2, K2: 0.31 meq. min -1/2, for the selected formula and KCL- retard Zyma[R]] tablets, respectively. The results of this study indicate that the selected formula could be used to prepare sustained release tablets of potassium chloride

Comparative bioavailability and pharacokinetic study between the formulated sustained release potassium chloride tablets and KCL-retard Zyma [R] tablets II

The bioavailability of the formulated enteric coated sustained release potassium chloride tablets was measured from the urinary excretion data of the drug after a single does of 40 meq k+ [5 tablets]. The cumulative excretion data showed that 80% +/- 13.56 of the administered does was excreted within 24 hours. The bioavailability of the formulated tablets was 94.87% relative of the commercially available sugar coated KCL- retard Zyma [R] tablets

Utilization of nicotinamide as a complexing agent in the formulation of diazepam oral solution I

Diazepam is a benzodiazepine tranquilizer. It has limited aqueous solubility. Nicotinamide is a safe., non- toxic and non- irritating vitamin, used to enhance the solubility of poorly soluble drugs. In this study a new approach was achieved to prepare diazepam solution through utilizing nicotinamide as a complexing agent. The results indicated that the use of nicotinamide gave soluble and more stable formula for diazepam oral solution, where the shelf- life was about 6 years, compared to 2 years when using co-solvent alone. The results showed that combination of nicotinamide and co-solvent [s] together in the formulation lead to reduction in the amount of both of them, at the same time this combination reduced the shelf-life of the solutions in comparison to that containing nicotinamide alone. The results also indicated that diazepam undergoes hydrolysis at low and high PH in the prepared formulations with optimum stability at PH5 which is the most suitable one for the formulations. In addition the results showed that the buffer type, buffer concentration and ionic strength had no effect on the rate of hydrolysis of diazepam, in spite of its photochemical decomposition, with a shelf-life of 5.9 months. The results also indicated that diazepam was unstable when formulated in plastic containers with a loss of 24% of the drug with 4 months. The results of this study showed the successful use of nicotinamide as a complexing agent in the formulation of diazepam oral solution