RESUMO
Phenylpropanolamine HCl was initially microencapsulated with cellulose acetate butyrate, however, the microcapsules did not show acceptable sustained release. A reduction of the drug particle size prior to microencapsulation resulted in a reduction in drug release rate from the microcapsules. The desired drug release profile was attained only when the drug powder was replaced with a drug-resin complex in the microencapsulation process. The pH of the dissolution media had an effect on the drug release profile.
Assuntos
Fenilpropanolamina/administração & dosagem , Preparações de Ação Retardada , Composição de Medicamentos , Concentração de Íons de HidrogênioRESUMO
The binding of phenylbutazone (I) and oxyphenbutazone (II) to human serum albumin over pH 6.9-9.3 was studied by difference spectrophotometry and equilibrium dialysis. At each pH tested, there was higher binding affinity of I to human serum albumin than II. Equilibrium dialysis showed that over the pH 7-8.2 range both agents had a single high-affinity site and several sites of lower affinity, with the highest binding constant and number of binding sites at pH 7.4 for both I and II. Both techniques showed that the affinity of both drugs to albumin was higher for the neutral form than for the basic form and this transition occurred in both cases around the neutral region (7-7.4). Both the ionized and unionized forms of I and II participated in the binding. In the neutral region, magnesium ion increased the affinity of both drugs to albumin while chloride ion decreased it slightly.
Assuntos
Oxifenilbutazona/sangue , Fenilbutazona/sangue , Albumina Sérica/metabolismo , Fenômenos Químicos , Físico-Química , Cloretos , Diálise , Humanos , Concentração de Íons de Hidrogênio , Magnésio , Ligação Proteica , Conformação Proteica , Espectrofotometria UltravioletaRESUMO
Anthralin and its decomposition products were separated by both column chromatographic and TLC techniques. Two decomposition products were characterized by TLC, melting-point data, and UV and IR spectroscopy. Pure anthralin and its decomposition products also were determined quantitatively.
Assuntos
Antracenos/isolamento & purificação , Antralina/isolamento & purificação , Cromatografia em Gel , Cromatografia em Camada Fina , Contaminação de Medicamentos , Estabilidade de Medicamentos , Métodos , Espectrofotometria Infravermelho , Espectrofotometria Ultravioleta , TermodinâmicaRESUMO
The physicochemical effects of a dimethylpolysiloxane fluid as a vehicle for prednisolone on its stability and dissolution pattern were evaluated. No detectable degradation of prednisolone was noted during 8 weeks of storage at 4, 26 and 45 degressC. The release rate of prednisolone from its suspension in dimethylpolysiloxane was lower than that from the aqueous suspension. However, the amount of prednisolone released in 30 min from the aqueous suspension was only about 5.5% greater than that released from its suspension in the silicone fluid.
Assuntos
Dimetilpolisiloxanos , Prednisolona , Silicones , Interações Medicamentosas , Veículos Farmacêuticos , Soluções , Suspensões , Fatores de TempoRESUMO
Complex formation between salicylic acid and adenosine or adenosine triphosphate in 0.2m phosphate buffer at pH=7 was investigated as a potential factor contributing to the prolongation of acetylsalicylic acid-induced GI blood loss. Spectrophotemetric techniques were used to evalute the complexation. Concerntration dependency of the absorbance decrease was measured at 27 and 37 degrees C. The addition of salicylic acid to either adenosine or adenosine triphosplate solutions appeared also to cause a decrease in surface tension which may play a role in reducing platelet aggregation induced by adenosine diphosphate. The results obtained seem to support the opinion that the mechansim of acetylsalicylic acid-induced GI blood loss is due to a combination of both local and systemic effect.
Assuntos
Trifosfato de Adenosina , Adenosina , Aspirina/efeitos adversos , Hemorragia Gastrointestinal/induzido quimicamente , Salicilatos , Adenosina/análise , Trifosfato de Adenosina/análise , Fenômenos Químicos , Química , Concentração de Íons de Hidrogênio , Salicilatos/análise , Tensão SuperficialRESUMO
The stability of aspirin in decaglycerol tetraoleate, decaglycerol octaoleate, and decaglycerol decaoleate was studied at 4, 26, and 45 degrees. Degradation of aspirin in these polyglycerol esters was temperature dependent. Aspirin demonstrated the greatest stability in decaglycerol octaoleate and the lowest stability in decaglycerol tetraoleate at all temperatures studied. The hydroxyl value and the viscosity of the polyglycerol ester appeared to influence the stability of aspirin.
Assuntos
Aspirina/análise , Estabilidade de Medicamentos , Glicerol , Veículos Farmacêuticos , Polímeros , Solubilidade , TemperaturaRESUMO
Investigation of possible enhancement of dissolution of acetylsalicylic acid via coprecipitation with polyethylene glycol 6000 was carried out. The results indicated that the initial amount of acetylsalicylic acid released from its coprecipitates or physical mixtures with polyethylene glycol 6000 was increased over that amount released from plain acetylsalicylic acid powder during the same period of time. This was attributed to lowering of the surface tension of the dissolution medium imparted by polyethylene glycol 6000. The effect of particle size of the coprecipitate on the dissolution rate of acetylsalicylic acid was also studied. Greater viscosity values produced by higher concentrations of polyethylene glycol 6000 in the coprecipitates appeared also to influence the dissolution rate of acetylsalicylic acid. The use of optimum concentration of polyethylene glycol 6000 in physical mixtures or coprecipitates would seem advantageous in the preparation of solid dosage forms containing acetylsalicylic acid.
