RESUMO
The aim of the present work was to prepare and evaluate sustained release liquisolid compact formulations of tramadol hydrochloride. The dissolution profile of the prepared compacts was also compared to that of a marketed preparation. Liquisolid sustained release formulations were prepared by using HPMC K4M as a sustained release agent. Precompression studies of characteristics such as flow properties were also carried out. Liquisolid compacts were evaluated by hardness, friability, and in vitro dissolution studies. Comparison of dissolution profiles was carried out by using a modelindependent, model-dependent, and statistical approach. The prepared liquisolid compacts are new dosage forms with better sustained release behavior compared to a marketed sustained formulation. The dissolution profile followed the Peppas model as "best fit" model. Two-way ANOVA results revealed a significant difference in dissolution profiles. This systematic approach to producing a formulation was found to help with analyzing the sustained release of tramadol hydrochloride. The use and evaluation of model-dependent methods is more complicated. These methods provide an acceptable model approach that indicates the true relationship between percent drug release and time variables, including statistical assumptions.
RESUMO
The aim of this research was to develop different ophthalmic gels of gatifloxacin using mucoadhesive polymers. To improve intraocular delivery of topically applied drugs such as gatifloxacin, gel formulations were prepared since solutions have a shorter ocular residence time because of tear turnover. A 3(2) factorial design was used to investigate the combined effect of two independent formulation variables in the preparation of the gels. Nine batches were prepared as per experimental design and evaluated for gelation temperature, gel strength, bioadhesion, viscosity, permeation, and antimicrobial efficacy. A surface plot was also created to graphically represent the effect of the independent variables on the evaluation parameters. Drug polymer compatibility was evaluated by differential scanning calorimetry and Fourier transform infrared spectroscopy. The prepared gels were observed to have a satisfactory gelation temperature, gel strength, and bioadhesion. Rheological study of the formulations indicated that gels exhibited pseudoplastic rheology. A modified device was used to evaluate drug permeation through a sheep's corneal membrane. In vitro permeation studies showed that a Peppas model was the best-fit model. Antimicrobial studies also indicated efficacy comparable to that of a marketed formulation. This systematic approach to formulation design should help in investigating the effect of variables in formulation processing.
Assuntos
Géis , Polímeros , Química Farmacêutica , Temperatura , ViscosidadeRESUMO
The purpose of the present study was to develop ophthalmic gel formulations of fluconazole. Intraocular delivery of topically applied drugs such as fluconazole is hampered by elimination of the solution due to tear turnover, so an in situ gelling thermoreversible mucoadhesive gel was formulated. Thermoreversible mucoadhesive gels were prepared using the cold method along with poloxamer 407 and different mucoadhesive polymers such as hydroxy ethyl cellulose (HEC), hydroxy propyl methyl cellulose (HPMC) K4M, and polyvinyl pyrrolidone (PVP) K30. Gels were evaluated for physical parameters like appearance, gelation temperature, pH, spreadability, drug content, gel strength, bioadhesion, and in vitro permeation. A modified device (modified K-C diffusion cell with a sheep's eye corneal membrane as a diffusion membrane) was used for evaluation of drug permeation through a sheep's corneal membrane. The formulated gels were transparent, uniform in consistency, and had spreadability with a pH range of 6.8 to 7.3. Satisfactory bioadhesion on the sheep's corneal surface and good gel strength were also observed. Diffusion studies have shown that a matrix is the best-fit model. As the concentration of mucoadhesive agent increases, the rate of permeation decreases. The order of drug permeation through the membrane was HEC > PVP K30 > HPMC K4M. This study found that a thermoreversible polymer and mucoadhesive polymers can be effectively used to prolong residence time.
RESUMO
The purpose of this research was to study mucoadhesive microspheres of tramadol hydrochloride compressed into tablet along with a loading dose. Microspheres containing tramadol hydrochloride were prepared by employing sodium alginate in combination with a mucoadhesive polymer, i.e., Carbopol 971P. An orifice-ionic gelation method was used to prepare the microspheres. A 3(2) factorial design was used to investigate the combined effect of two independent formulation variables in the preparation of microspheres. The concentration of sodium alginate (X(1)) and carbopol 971P (X(2)) were selected as independent variables. Nine batches were used in the experimental design and evaluated for swelling index, mucoadhesion, and drug entrapment efficiency. A surface plot is presented to graphically represent the effect of the independent variables on the evaluation parameters. The best batch exhibited drug entrapment efficiency of 70.12%, swelling index of 2.3 and mucoadhesion of 95.42%. Microspheres showing maximum drug entrapment were compressed with the loading dose and subjected to in vitro dissolution studies. Drug release from tablets was found to follow a matrix model. Initial burst release from these tablets indicated the release of the loading dose and then a sustained effect over the time. This modified approach to formulation of tablets was found to be effective in sustaining drug release.
