Entrapment Efficiency Of Microspheres Research Articles

Preparation and evaluation of naringin-loaded polycaprolactone microspheres based oral suspension using Box-Behnken design

The objective of the current investigation was to study the outcome of the concentration of polycaprolactone (PCL), the concentration of polyvinyl alcohol (PVA) and the concentration of hydroxypropyl methylcellulose (HPMC) on the average particle size of microspheres and the drug entrapment efficiency of naringin-loaded polycaprolactone microspheres based oral suspension. Naringin-loaded polycaprolactone microspheres based oral suspension were prepared by solvent evaporation method. Further, in this work optimization of the formulation was done using a three factors, three levels Box-Behnken design (BBD). Drug-loaded microsphere suspension was prepared by employing solvent evaporation technique. Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) analysis was carried out to determine any incompatibility between the naringin and other components used in the formulations. Polymer alone (PVA concentration) or interaction effects of polymers (PCL-HPMC, PCL-PVA, HPMC-PVA, and PCL in higher order) have a substantial influence on particle size of microspheres. Amount of PVA and HPMC have a significant effect on entrapment efficiency of microspheres. The optimal conditions of PCL concertation were 7.7% w/v; HPMC concentration was 3.2% w/v and PVA concentration was 0.081% w/v. The optimized suspension showed particle size of 24μm with drug entrapment efficiency 96%. As a result, due to uniform distribution of microspheres, drug entrapment efficiency was achieved in optimized suspension.

FORMULATION AND EVALUATION OF MICROSPHERES FOR NASAL DELIVERY OF ANTI-HYPERTENSIVE DRUG

Lisinopril is used in the treatment of hypertension and heart failure in myocardial infarction and also in diabetic nephropathy. It is very poorly absorbed from GIT. Intranasal administration is an ideal alternative to the parenteral route for systemic drug delivery. Formulating multiparticulate system with mucoadhesive polymers may provide a significant increase in the nasal residence time. The microspheres prepared by emulsion solvent evaporation method were characterized for encapsulation efficiency, drug loading, particle size, surface morphology, degree of swelling, ex vivo mucoadhesion, drug release and ex vivo diffusion studies. Entrapment efficiency of microspheres was in range of 84.95±0.50% to 97.44±0.61% mucoadhesion was 83.76% and 94.41% and drug release up to 40 minutes was 53.66% to 88.32%. In ex vivo studies, the microspheres showed good bioavailability by nasal route compared to oral drug administration. Both in vitro and in vivo studies conclude that combination of Carbopol and HPMC based microspheres are better than single carbopol-based formulation for the delivery of lisinopril.

Development and Evaluation of Microsphere Based Topical Formulation using Design of Experiments

The aim of this work is to develop microsphere formulation and study the impact of drug-polymer ratio, surfactant concentration and stirring speed on particle size and drug entrapment during preparation. Clotrimazole loaded Eudragit S100 microspheres were prepared by emulsion solvent evaporation method. A three level factorial Box Behnken design was used to characterize and optimize the formulation. The result of analysis of variance test indicated that the test is significant. The optimum drug: polymer ratio (X1), surfactant concentration (X2) and stirring speed (X3) was found to be 1:4, 1.5% and 1000 rpm respectively to obtain particle size and maximum entrapment efficiency of microspheres as 35.6 µm and 83.3%, respectively. The drug release from microsphere based cream exhibited a controlled release pattern.

Design and Characterization of Mucoadhesive Microspheres for Gastro- Retentive Delivery of Famotidine Hydrochloride

This article illustrates the Design and Characterization of Mucoadhesive microspheres with Famotidine Hydrochloride as drug for Gastro-Retention of drug release. The microspheres were prepared by the Ion Gelation method and Thermal Cross Linking Method. In Ion Gelation method sodium alginate is used as a release controlling biopolymer and Calcium chloride is acts as hygroscopic cross linking agent. In Thermal Cross Linking Method egg albumin is used as binding agent and a Thermal energy is used as cross linking property. The characteristics like shape and structure of prepared microspheres by Optical microscopy and scanning electron microscopy, respectively. In vitro drug release studies were done and drug release was evaluated. Effect on the Mucoadhesion, drug Entrapment Efficiency of microspheres and Drug release were observed. The prepared microspheres exhibited prolonged drug release (17 hrs) the mean particle size increased as the concentration of sodium alginate increased, as the egg albumin concentration increases the Mucoadhesion increased and the drug release rate decreased at higher concentration of sodium alginate. Significant effect of the Encapsulation Efficiency of microspheres was observed. In vitro studies demonstrated the Gastro retentive delivery of drug from the microspheres.

English

Advancement in drug delivery could come from innovating improvement to the existing drug delivery system. Lornoxicam (Lxm) loaded ethyl cellulose microspheres were prepared by emulsion solvent evaporation technique and also to investigate the effect of variations in drug concentration, polymer concentration, internal phase volume, continuous phase volume and emulsifier concentration on the particle size, shape, % yield, percent entrapment efficiency and in vitro drug release behavior. The scanning electron microscopy (SEM) revealed that microspheres had good spherical geometry with smooth surface. The result showed that the maximum yield of the microspheres was found to be 64.23 ± 0.25%, with particle size in the range of 64.24 ± 1.82 to 81.83 ± 3.43 μm and encapsulation efficiency was found to be in a range of 60.34 ± 1.63 to 71.61 ± 1.20%. The average particle size and entrapment efficiency of microspheres were enhanced with increasing polymer concentration but reduced with increasing internal phase volume, external phase volume and emulsifier concentration. In vitro release profile of microspheres was in the range of 75.65 ± 2.3 to 87.78 ± 2.3% at the end of 12 h. It was concluded that Lxm loaded ethyl cellulose microspheres formulation showed sustained effect over a period of 12 h. Key words: Ethyl cellulose, lornoxicam, microspheres, solvent evaporation, sustained release.

Carbon Nanotube as Adsorbent for Floating Microspheres of Diltiazem Hydrochloride

Diltiazem hydrochloride (DTZ), a highly water soluble antihypertensive drug, was used as a model drug for the incorporation of drug‐carbon nanotube adsorbates microspheres. These microspheres were characterized by yield, drug entrapment efficiency, micromeritics, flow properties, buoyancy, scanning electron microscopy (SEM), powder X‐ray diffractometry (PXRD) and drug release kinetics. Studies on carbon nanotubes (CNT) doped microspheres showed that the total yield of microspheres was independent of CNTs incorporated. Size, shape, circularity and flow properties of microspheres for all batches were not affected by the incorporation of CNTs. Microspheres of all batches had uniform size distribution, very good shape and circularity as well as flow properties. Drug entrapment efficiency of microspheres containing adsorbates was more compared to microspheres containing drug alone; hence CNTs can be considered as a good carrier for improving drug entrapment. Drug entrapment efficiency was found to be 82–94wt.% for CNT doped microspheres while only 63–74wt.% for microspheres without CNTs. Buoyancy of the microspheres containing CNT was found to be little bit more (77–86%) as compared to the buoyancy of microspheres without CNT (77–81%). Drug was released completely in 10 hours from microspheres without CNT, while only 50–60% of drug was released from CNT microspheres in 10 hours and the release of drug followed Higuchi matrix model due to diffusion of drug through the microspheres. From the existing data it was concluded that physical interaction between drug and CNTs exists, and being inert in nature, they can be used as novel carriers for extended drug release purpose and improving drug entrapment efficiency of microspheres.

Formulation optimization of double emulsification method for preparation of enzyme-loaded Eudragit S100 microspheres

The present study aimed to develop an oral sustained release microparticulate system for acid labile enzyme-Serratiopeptidase. A 32 full factorial experiment was designed to study the effects of the external aqueous phase volume and stabilizer (Tween® 80) concentration on the entrapment and size of Eudragit S100 microspheres prepared by a modified double emulsion solvent evaporation technique. The results of analysis of variance tests for both effects indicated that the test is significant. The effect of external aqueous phase volume was found to be higher on the entrapment efficiency of microspheres (SSY1 = 1362.63; SSY2 = 250.13), whereas Tween® 80 produced a significant effect on size of microspheres (SSY1 = 944.01; SSY2 = 737.26). Scanning electron microscopy of microspheres demonstrated smooth surface spherical particles. The effect of formulation variables on the integrity of enzyme was confirmed by in vitro proteolytic activity. Microspheres having maximum drug encapsulation (81.32 ± 3.97) released 4–5% enzyme at pH 1.2 in 2 h. The release of enzyme from microspheres followed Higuchi kinetics (R2 = 0.987). In phosphate buffer, microspheres showed an initial burst release of 25.65 ± 2.35% in 1 h with an additional 62.96 ± 4.09% release in the next 5 h. Thus, formulation optimization represents an economical approach for successful preparation of Eudragit S100 microspheres involving fewest numbers of experiments.