Controlled release metformin hydrochloride microspheres of ethyl cellulose prepared by different methods and study on the polymer affected parameters.

The objectives of this investigation were to prepare microspheres of the anti-diabetic drug, metformin hydrochloride, using ethyl cellulose as the polymer and evaluate the encapsulation efficiency and release characteristics in vitro and in vivo; utilizing different microencapsulation techniques. Different proportions of polymer were used to obtain varying drug-polymer ratios. Physical properties, loading efficiency and dissolution rate were dependent on the method chosen for preparation and also on the drug-to-polymer ratio. The addition of surfactant during emulsification and petroleum ether in non-solvent addition process affected release of drug and also size distribution of microspheres. To investigate the type of mechanism that occurs, dissolution data were plotted according to different kinetic models. In vitro release studies show first order and Higuchi model release characteristics being exhibited. All the results were treated statistically to validate the findings. Significant differences in percentage yield, entrapment efficiency and sustaining capacity were seen with microspheres prepared by two different methods. In vivo studies in normal and hyperglycemic mice show faster glucose reduction with microspheres prepared by the evaporation method, whereas the release sustaining effect was more pronounced with microspheres prepared by the non-solvent addition method.

Role of Squash Cytology in Intraoperative Diagnosis of Spinal Lesions.

BACKGROUND: Squash cytology for intra operative diagnosis of central nervous system (CNS) tumors is an immensely important modality. Though its role in brain lesions is unquestionable and has been proven in a number of studies, its utility for spinal lesions is still a grey zone. AIMS: To assess the diagnostic accuracy of squash preparation in spinal lesions and its statistical significance (sensitivity, specificity, positive predictive value, negative predictive value) following histological confirmation. MATERIALS AND METHODS: A total of 57 cases of spinal tumors were taken. May-Grunewald-Giemsa staining (MGG) and Hematoxylin-Eosin (H&E) were done in each one of them. Rest of the tissue was processed for histological diagnosis and results were compared. RESULTS: In our study, histology was taken as the gold standard. By comparing the results, squash preparation had sensitivity of 95.75%, specificity 80.0%, positive predictive value (PPV)95.74%, and negative predictive value (NPV) 80.80%. Schwannoma was found to be the most prevalent tumor in the spine (17/57) in our study, followed by meningioma (13/57). Diagnostic accuracy for schwannoma was fairly high i.e. 92.3%, followed by meningioma (82.35%). Highest diagnostic accuracy was documented in intradural, extramedullary compartment. CONCLUSION: Inspite of having pitfalls and various limitations in case of spinal lesions, squash preparation is a rapid and easy method with fairly high diagnostic accuracy. So it can be reliably used as an intraoperative diagnostic tool in spinal lesions.

Co-infection of Candidaparapsilosis in a Patient of Pulmonary Actinomycosis-A Rare Case Report.

The diagnosis of pulmonary actinomycosis is difficult and less than 10% of cases are diagnosed at the initial presentation. Actinomycosis is always poly-microbial flora infection in human. On the other hand, Candida parapsilosis is an emerging fungal pathogen especially in immuno-compromised patients. Combined bacterial-fungal infection increases frequency and severity of the disease. This report is a case of a Candida parapsilosis co-infection in a 23-year-old male patient having pulmonary actinomycosis. This thereby could guide the clinicians towards an appropriate therapy.

Design and in vitro evaluation of floating drug delivery system for an antipsychotic agent: a technical report.

Floating drug delivery systems are used to target drug release in the stomach or to the upper parts of the intestine. The oral delivery of the anti-psychotic agent carbamazepine was facilitated by preparing a non-disintegrating floating dosage form which can increase its absorption in the stomach by increasing the drug's gastric residence time. The polymers used were HPMC (low and high viscosity), guar gum, and carbopol, along with sodium bicarbonate as the gas-generating agent. The prepared tablets were evaluated for their physicochemical properties and drug release. In vitro release studies indicated that the carbamazepine release from the floating dosage forms was uniform and followed a zero-order release. It was observed that the devices containing higher proportions of HPMC (high viscosity) showed slower release than those containing lower proportions while also maintaining the integrity of the device (> or = 24 h). The incorporation of guar gum helps to maintain the device's integrity, and due to its viscolysing property also affects the drug's release profile. Sodium bicarbonate which was used as the gas-generating agent causes the tablet to float for the required time (> or = 24 h).

HPLC method for estimation of metformin hydrochloride in formulated microspheres and tablet dosage form.

A simple, accurate, economical and reproducible HPLC method has been developed for quantitative estimation of metformin hydrochloride from tablet dosage form and formulated microspheres. The developed HPLC method is a reverse phase chromatographic method using phenomenex C(18) column and acetonitrile:phosphate buffer (65:35) pH adjusted to 5.75 with o-phosphoric acid as mobile phase and glipizide as internal standard. The linearity was observed in concentration range of 0-25 mug/ml for metformin hydrochloride. Results of analysis were validated statistically and by recovery studies.

Cellulose acetate microspheres as floating depot systems to increase gastric retention of antidiabetic drug: formulation, characterization and in vitro-in vivo evaluation.

Gastric emptying is a complex process that is highly variable and makes the in vivo performance of drug delivery systems uncertain. In order to avoid this variability, efforts have been made to increase the retention time of the drug delivery systems for more than 12 hours utilizing floating or hydrodynamically controlled drug delivery systems. The objective of this investigation was to develop a floating, depot-forming drug delivery system for an antidiabetic drug based on microparticulate technology to maintain constant plasma drug concentrations over a prolonged period of time for effective control of blood sugar levels. Formulations were optimized using cellulose acetate as the polymer and evaluated in vitro for physicochemical characteristics and drug release in phosphate buffered saline (pH 7.4), and evaluated in vivo in healthy male albino mice. The shape and the surface morphology of the prepared microspheres were characterized by optical microscopy and scanning electron microscopy. In vitro drug release studies were performed and drug release kinetics were calculated using the linear regression method. Effects of stirring rate during preparation and polymer concentration on the size of microspheres and drug release were observed. The prepared microspheres exhibited prolonged drug release (more than 10 hours) and remained buoyant for over 10 hours. Spherical and smooth-surfaced microspheres with encapsulation efficiency ranging from 73% to 98% were obtained. The release rate decreased and the mean particle size increased at higher polymer concentrations. Stirring speed affected the morphology of the microspheres. This investigation revealed that upon administration, the biocompatible depot-forming polymeric microspheres controlled the drug release and plasma sugar levels more efficiently than plain orally given drug. These formulations, with their reduced frequency of administration and better control over drug disposition, may provide an economic benefit to the user compared with products currently available for diabetes control.