An evaluation of microcrystalline cellulose attributes affecting compaction-induced pellet coat damage through a multi-faceted analysis

Pellet coat damage in multi-unit pellet system (MUPS) tablets has previously been studied and addressed with limited success. The effects of lactose filler material attributes on pellet coat damage have been relatively well-studied but a similar understanding of microcrystalline cellulose (MCC) is lacking notwithstanding its high cushioning potential. Hence, the relationships between MCC attributes and pellet coat damage were investigated. Single pellet in minitablets (SPIMs) were used to isolate pellet-filler effects and reveal the under-unexplored impact of risk factors found in MUPS tablets. MUPS tablets and SPIMs were prepared with various grades of MCC and pellets with an ethylcellulose or acrylic coat at various compaction pressures. Subsequently, the extent of pellet coat damage was determined by dissolution test and quantified using two indicators to differentiate the nature of the damage. A multi-faceted analytical approach incorporated linear regression, correlations and a classification and regression tree algorithm and evaluated how MCC attributes, such as flowability, particle size and plastic deformability, exert various influences on the extent of ethylcellulose and acrylic pellet coat damage. This analysis improved the understanding of the different mechanisms by which pellet coat damage to these two polymer types occurs which can help enhance future pellet coat damage mitigation strategies.

Cellulose-based matrix microspheres of prednisolone inclusion complex: preparation and characterization

The purpose of the present investigation was to encapsulate pure prednisolone (PRD) and PRD-hydroxypropyl-β-cyclodextrin (HPβCD) complex in cellulose-based matrix microspheres. The system simultaneously exploits complexation technique to enhance the solubility of low-solubility drug (pure PRD) and subsequent modulation of drug release from microspheres (MIC) at a predetermined time. The microspheres of various compositions were prepared by an oil-in-oil emulsion-solvent evaporation method. The effect of complexation and presence of cellulose polymers on entrapment efficiency, particle size, and drug release had been investigated. The solid-state characterization was performed by Fourier transform infrared spectroscopy, thermogravimetry, differential scanning calorimetry, and powder X-ray diffractometry. The morphology of MIC was examined by scanning electron microscopy. The in vitro drug release profiles from these microspheres showed the desired biphasic release behavior. After enhancing the solubility of prednisolone by inclusion into HPβCD, the drug release was easily modified in the microsphere formulation. It was also demonstrated that the CDs in these microspheres were able to modulate several properties such as morphology, drug loading, and release properties. The release kinetics of prednisolone from microspheres followed quasi-Fickian and first-order release mechanisms. In addition to this, the f (2)-metric technique was used to check the equivalency of dissolution profiles of the optimized formulation before and after stability studies, and it was found to be similar. A good outcome, matrix microspheres (coded as MIC5) containing PRD-HPβCD complex, showed sustained release of drug (95.81%) over a period of 24 h.

Development of colon targeted multiparticulate pulsatile drug delivery system for treating nocturnal asthma

The aim of the present study was to develop theophylline fast release enteric-coated pellets as a pulsatile drug delivery to the colon. The novelty of this work is the combination of pH and time-dependant enteric polymers as a single coating for the development of multiparticulate formulation. Theophylline pellets were optimized by applying a 2-factors 3-levels full factorial design. Continuous dissolution studies were carried out in simulated gastric, intestinal, and colonic fluid with pH 1.2 (0.1 N HCl), pH 7.4 and pH 6.8 (phosphate buffer), respectively. The lag time prior to the drug release was highly affected by combination of two factors, i.e. the percentage of Eudragit RL100 in polymer mixture and coating level. The formulation containing Eudragit RL100 and Eudragit S100 with a ratio of 4:1 and coating level of 12%w/w was found to be optimum. The results of serum study in New Zealand rabbits showed that the developed formulation provided a significant lag phase of 5 h. The present study demonstrates that the theophylline enteric-coated pellets could be successfully colon targeted by the design of pH- and time-dependant modified chronopharmaceutical formulation. In conclusion, pulsatile drug release over a period of 3-12 h is consistent with the requirements for chronopharmaceutical drug delivery.

In vitro evaluation of coating polymers for enteric coating and human ileal targeting

Recombinant interleukin-10 producing Lactococcus lactis is an alternative therapy for Crohn's disease. For in vivo interleukin-10 production, thymidine, the essential feed component of these recombinant bacteria should be coadministered. Different coating polymers were evaluated in vitro for enteric properties and targeting suitability to the ileum, the major site of inflammation in Crohn's disease. To guarantee ileal delivery, the polymer must dissolve from pH 6.8 and allow complete release within 40 min. Aqoat AS-HF coated pellets (15%) showed poor enteric properties and thymidine was released below pH 6.8. Eudragit FS30D coated pellets (15%) showed good enteric properties, but no thymidine was released within 40 min at pH 6.8. Eudragit S coated pellets (15%) showed good enteric properties after curing at elevated temperature while no thymidine was released within 40 min at pH 6.8. In another approach to pass the proximal small intestine intact, pellets were coated with 30% Eudragit L30D-55. At pH 6.0, they showed a lag-phase of 20 min. No influence of layer thickness was seen above pH 6.5. Alternatively, pellets were coated with a mixture of Eudragit FS30D/L30D-55 but they showed poor enteric properties and thymidine was released below pH 6.8. In conclusion, none of the tested polymers/mixtures ensured enteric properties and ileal targeting.

Novel Chewable Sustained‐Release Tablet Containing Verapamil Hydrochloride

The aim of this research is to produce a compactable self-sealing chewable tablet of verapamil hydrochloride. Tablets were prepared by compressing beads coated with multiple layers including drug, hydroxypropyl methylcellulose, polyethylene oxide, ethylcellulose, lactose, and sodium starch glycolate. Dissolution studies were carried out according to the USP XXII paddle method for 14 h. A new tablet formulation was evaluated in three different forms: 1) whole tablet, 2) crushed tablet using a commercial tablet crusher, and 3) tablet chewed in the mouth and then expelled into dissolution fluid. Sustained release from the new formulation was maintained and was similar in all three different treatments, and similar to drug release from intact commercially available Isoptin SR, but crushing or chewing destroyed the sustained release property of Isoptin SR (as expected). This new formulation can be administered either by swallowing the whole tablet or by first crushing or chewing the tablet. Controlled release properties of this new formulation do not change by chewing or crushing the tablet first. Such a tablet could be valuable for all patients including those who have difficulty swallowing, such as pediatrics and geriatrics.

The influence of water content and drug solubility on the formulation of pellets by extrusion and spheronisation

The influence of drug solubility in the range 14.3-1000 gl-1 on the formation of pellets by extrusion and spheronisation has been investigated by evaluating the performance of a series of model drugs mixed with an equal part by weight of microcrystalline cellulose. The optimum formulation in terms of pellet roundness and the maximum quantity within a limited size range was established by preparing samples with a range of water levels. The range of water levels over which pellets could be formed was found to be dependent on the model drug and its particle size. In general the force necessary to extrude the wet mass through the ram extruder was found to decrease as the quantity of water added increased. The optimum water level required to form the best quality pellets was found to decrease as a linear function of the natural logarithm of the water solubility of the drug. If allowance is made for the loss of solid by dissolution of the drug, there is an increase in the apparent water content necessary to form good spheres above a critical solubility between 350 and 400 gl-1.

Design of a new multiparticulate system for potential site-specific and controlled drug delivery to the colonic region

A multiparticulate dosage form consisting of a hydrophobic core coated with a pH-dependent polymer is proposed for colonic specific delivery of drugs. Different approaches for colon-specific drug delivery have been studied over the last decade, including prodrugs, polymeric coating using pH-sensitive or bacterial degradable polymers and matrices. In this work, we present a new multiparticulate system to deliver active molecules to the colonic region, which combines pH-dependent and controlled drug release properties. This system was constituted by drug loaded cellulose acetate butyrate (CAB) microspheres coated by an enteric polymer (Eudragit(R) S). Both, CAB cores and pH-sensitive microcapsules, were prepared by the emulsion-solvent evaporation technique in an oily phase. Ondansetron (OS) and budesonide (BDS), two interesting drugs with a potentially new application for the local treatment of intestinal disorders, were efficiently microencapsulated in CAB microspheres at different polymer concentrations (6 and 8%). These hydrophobic cores (about 60 and 110 micrometer in size, respectively) were then microencapsulated with Eudragit(R) S, resulting in multinucleated structures, except in the case of BDS-CAB microspheres prepared at 8% CAB concentration, in which more mononucleated microcapsules were obtained. The in vitro drug release studies of pH-sensitive microcapsules containing the hydrophobic cores showed that no drug was released below pH 7. After that, CAB microspheres efficiently controlled the release of BDS, the release behavior being affected by the different polymer concentration used in their preparation. However, OS-CAB microspheres did not maintain their controlled-release properties once the enteric polymer dissolved. The extraction of the drug by the Eudragit(R) solvent during the second microencapsulation process was in this case the cause for the failure of the controlling release mechanism.