Formulation and in vitro evaluation of pellets containing sulfasalazine and caffeine to verify ileo-colonic drug delivery

The ColoPulse coating is a pH-dependent coating that can be used to target drug release to the ileo-colonic region. ColoPulse coated tablets and capsules have demonstrated their targeting capabilities in vivo in more than 100 volunteers and patients. However, so far the ColoPulse coating has not been used for multi-particulate pellet formulations. The sulfasalazine–caffeine method can be used to confirm ileo-colonic drug delivery in vivo. Caffeine serves as a release marker in this method, while sulfasalazine serves as a marker for colonic arrival. In this study, extrusion–spheronization was used to produce microcrystalline cellulose based pellets containing both caffeine and sulfasalazine. Dissolution tests revealed that a superdisintegrant, i.e., croscarmellose sodium or sodium starch glycolate, should be incorporated in the formulation to achieve acceptable release profiles for both sulfasalazine and caffeine. However, acceptable release profiles were only obtained when the pelletizing liquid consisted of ethanol/water 1/1 (v/v) but not with pure water. This phenomenon was ascribed to the differences in the degree of swelling of the superdisintegrant in the pelletizing liquid during the granulation process. The pellets were coated with the ColoPulse coating and showed the desired pH-dependent pulsatile release profile in vitro. In future clinical studies, ileo-colonic targeting should be verified

CLSM as Quantitative Method to Determine the Size of Drug Crystals in a Solid Dispersion

PURPOSE: To test whether confocal laser scanning microscopy (CLSM) can be used as an analytical tool to determine the drug crystal size in a powder mixture or a crystalline solid dispersion. METHODS: Crystals of the autofluorescent drug dipyridamole were incorporated in a matrix of crystalline mannitol by physical mixing or freeze-drying. Laser diffraction analysis and dissolution testing were used to validate the particle size that was found by CLSM. RESULTS: The particle size of the pure drug as determined by laser diffraction and CLSM were similar (D(50) of approximately 22 μm). CLSM showed that the dipyridamole crystals in the crystalline dispersion obtained by freeze-drying of less concentrated solutions were of sub-micron size (0.7 μm), whereas the crystals obtained by freeze-drying of more concentrated solutions were larger (1.3 μm). This trend in drug crystal size was in agreement with the dissolution behavior of the tablets prepared from these products. CONCLUSION: CLSM is a useful technique to determine the particle size in a powder mixture. Furthermore, CLSM can be used to determine the drug crystal size over a broad size distribution. A limitation of the method is that the drug should be autofluorescent

Development of a dry, stable and inhalable acyl–homoserine–lactone–acylase powder formulation for the treatment of pulmonary Pseudomonas aeruginosa infections

In the lungs of cystic fibrosis (CF) patients, Pseudomonas aeruginosa commonly causes chronic infections. It has been shown that the P. aeruginosa quorum sensing (QS) system controls the expression of virulence factors during invasion and infection to host cells. PvdQ is an acyl–homoserine lactone (AHL) acylase able to degrade the signal molecule of P. aeruginosa QS. The role of PvdQ in inhibiting the QS and its successive virulence determinants has been established in in vitro as well as in in vivo, the latter in a Caenorabdhitis elegans model. For the treatment of pulmonary P. aeruginosa infections, we propose that PvdQ can be best administered directly to the lungs of the patients as a dry powder because this is expected to give specific advantages in delivery as compared to nebulizing. Therefore in this study we investigated the production of a PvdQ powder by spray-freeze drying using mannitol, trehalose and inulin as excipient. The activity of PvdQ in the powder was determined immediately after production and after subsequent storage during 4 weeks at 20 °C and 55 °C. We found that the enzymatic activity of PvdQ is fully maintained during spray-freeze drying using mannitol, trehalose or inulin as excipient. However, mannitol was not able to stabilize the protein during storage, while PvdQ incorporated in trehalose or inulin was fully stabilized even during storage at 55 °C for at least 4 weeks. The poor stabilizing capacities of mannitol during storage could be related to its crystalline nature while the excellent stabilizing capacities of trehalose and inulin during storage could be related to their amorphous nature. The trehalose and inulin-based particles consisted of porous spheres with a volume average aerodynamical diameter of ∼1.8 μm implying that they are suitable for pulmonary delivery. This is the first study in which an AHL-degrading enzyme is processed into spray-freeze-dried powder suitable for inhalation

Performance of Tablet Splitters, Crushers, and Grinders in Relation to Personalised Medication with Tablets

Swallowing problems and the required dose adaptations needed to obtain optimal pharmacotherapy may be a hurdle in the use of tablets in daily clinical practice. Tablet splitting, crushing, or grinding is often applied to personalise medication, especially for the elderly and children. In this study, the performance of different types of (commercially available) devices was studied. Included were splitters, screwcap crushers, manual grinders, and electric grinders. Unscored tablets without active ingredient were prepared, with a diameter of 9 and 13 mm and a hardness of 100–220 N. Tablets were split into two parts and the difference in weight was measured. The time needed to pulverise the tablets (crush time) was recorded. The residue remaining in the device (loss) was measured. The powder was sieved to obtain a particle fraction >600 µm and <600 µm. The median particle size and particle size distribution of the later fraction were determined using laser diffraction analysis. Splitting tablets into two equal parts appeared to be difficult with the devices tested. Most screwcap grinders yielded a coarse powder containing larger chunks. Manual and especially electric grinders produced a finer powder, making it suitable for administration via an enteral feeding tube as well as for use in individualised preparations such as capsules. In conclusion, for domestic and incidental use, a screwcap crusher may provide sufficient size reduction, while for the more demanding regular use in hospitals and nursing residences, a manual or electric grinder is preferred

Compaction properties of isomalt

Although other polyols have been described extensively as filler-binders in direct compaction of tablets, the polyol isomalt is rather unknown as pharmaceutical excipient, in spite of its description in all the main pharmacopoeias. In this paper the compaction properties of different types of ispomalt were studied. The types used were the standard product sieved isomalt, milled isomalt and two types of agglomerated isomalt with a different ratio between 6-O-alpha-D-glucopyranosyl-D-sorbitol (GPS) and 1-O-alpha-D-glucopyranosyl-D-mannitol dihydrate (GPM). Powder flow properties, specific Surface area and densities of the different types were investigated. Compactibility was investigated by compression of the tablets on a compaction Simulator, simulating the compression oil high-speed tabletting machines. Lubricant sensitivity was measured by compressing unlubricated tablets and tablets lubricated with 1% magnesium stearate oil all instrumented hydraulic press. Sieved isomair had excellent flow properties but the compactibility was found to be poor whereas the lubricant sensitivity was high. Milling resulted in both a strong increase in compactibility as an effect of the higher surface area for bonding and a decrease in lubricant sensitivity as an effect of the higher Surface area to be coated with magnesium stearate. However, the flow properties of milled isomalt were too bad for use as filler-binder in direct compaction. just as could be expected, agglomeration of milled isomalt by fluid bed agglomeration improved flowability. The good compaction properties and the low lubricant sensitivity were maintained. This effect is Caused by all early fragmentation of the agglomerated material during the compaction process, producing clean, lubricant-free particles and a high Surface for bonding. The different GPS/GPM ratios of the agglomerated isomalt types Studied had no significant effect oil the compaction properties. (C) 2009 Elsevier B.V. All rights reserved

Development of a zero-order sustained-release tablet containing mesalazine and budesonide intended to treat the distal gastrointestinal tract in inflammatory bowel disease

Ulcerative colitis (UC) and Crohn's disease (CD) are diseases affecting the gastrointestinal tract. Treatment depends on the severity of the disease, site of inflammation, and patient's response. The aim of this study was to develop a zero-order sustained-release tablet containing both the anti-inflammatory drugs mesalazine and budesonide as a new treatment option for ileo-colonic CD and UC. Tablets were attained by wet granulation with hydroxypropyl methylcellulose and direct compression. Our newly developed tablet core was coated with different ColoPulse (R) coating thicknesses and the mesalazine and budesonide release profiles were investigated in a 600-min gastrointestinal simulation system (GISS) experiment, together with commercially available MMX (R)-mesalazine and MMX (R)-budesonide. Lag-time, release rate (k(0)), completeness of release, and zero-order correlation coefficient (R-0(2)) could be manipulated by varying ColoPulse (R) coating thickness. Our newly developed combination preparation (C[4.92]) complied with all conducted European Pharmacopoeia tests as well as an accelerated 6-month stability test and had a lag-time of 250 min (simulated ileum targeted), a linear release profile (mesalazine R-0(2) = 0.9002; budesonide R-0(2) = 0.9481), and drug release of 100% mesalazine and 77% budesonide. Like C[4.92], MMX (R)-mesalazine had a linear (R-0(2) = 0.9883) and complete release profile (96%). However, C[4.92] lag-time was longer (250 vs. 210 min), assuring simulated ileum specificity. Remarkably, MMX (R)-budesonide lag-time was 480 min and release was only 7% with a linear character (R-0(2) = 0.9906). The in vitro results suggest that MMX (R)-budesonide effectiveness may be improved if budesonide release in the aqueous phase would be increased and that C[4.92] is a potential, new treatment option for ileo-colonic CD and UC. (C) 2016 Elsevier B.V. All rights reserved

Inulin as filler-binder for tablets prepared by direct compaction

The tabletting properties of a number of different amorphous inulin types were investigated. The types varied with respect to chain length, particle size and amount of included air in the particles. Powder flow properties and densities of the different types were investigated. Just as expected, it was found that the flow properties improved with increased particle size of the material. Compactibility was investigated by compression of tablets on a compaction simulator, simulating the compression on high-speed tabletting machines. The bonding capacity of all inulins was high. However, the lubricant sensitivity strongly varied among the different types of inulin. Generally, amorphous materials such as starches are highly lubricant sensitive, because they show ductile behaviour upon compaction. On the other hand, crystalline materials such as dicalcium phosphate dihydrate have a low lubricant sensitivity, because they fragment during compaction. A high lubricant sensitivity was indeed found for amorphous inulins with a low amount of entrapped air. In contrast, the lubricant sensitivity of the amorphous inulin was low when particles containing large amounts of air were compressed. Obviously entrapped air induces fragmentation of the powder particles by which the lubricant film, covering the particles, was destroyed. Tablets prepared from inulin did not disintegrate but they dissolved when incubated in water. The disintegration/dissolution time increased with decreasing chain length of the inulin. The addition of a disintegrant reduced the disintegration time. The somewhat slower dissolution of the longer chain inulin can be an advantage for chewable tablets or lozenges. It was concluded that inulin with large amounts of entrapped air is a good filler-binder and an attractive alternative to commonly used filler-binders. © 2002 Elsevier Science B.V. All rights reserved

The effect of vessel material on granules produced in a high-shear mixer

In this study the effect of different vessel wall materials on the granule size distributions obtained during high-shear granulation of different materials is investigated. The distributions obtained in glass and stainless steel vessels differ from those obtained in PMMA (polymethyl methacrylate) and PTFE (polytetrafluoroethylene) vessels. The high contact angle of PMMA forces all liquid immediately into the more easily wetted powder bed. In this vessel a fast liquid absorbing powder nucleates in the droplet controlled regime, leading to a narrow particle size distribution. In a vessel with a low contact angle (glass or stainless steel) a liquid layer can be formed on the wall surface. This liquid causes an inhomogeneous distribution of liquid over the powder bed; a broader granule size distribution is the result. With a powder that slowly absorbs liquid, local overwet areas can be created, resulting in large granules. This results in broader granule size distributions as well. In conclusion; the contact angle of the vessel material and the wetting rate of the powder used determine the granule growth process and the resulting granule size distribution. (C) 2004 Elsevier B.V. All rights reserved

Hollow filler-binders as excipients for direct compaction

PURPOSE: As an effect of their plastic deformation behavior, ductile materials create a large surface for bonding during compaction. However, a serious drawback is their high lubricant sensitivity, preventing the formation of strong bonds. The purpose of this study was both an increase in compactibility and a reduction of the lubricant sensitivity of ductile filler-binders by using hollow particles. This was illustrated for inulin. METHODS: Both solid and hollow inulin particles were prepared by spray-drying. Unlubricated tablets and tablets containing 0.5% magnesium stearate were compressed in a compaction simulator, operating at 300 mm/s. The tablet crushing strength was determined with a Schleuniger apparatus. RESULTS: The compaction of unlubricated, solid inulin particles showed that the product had good compatibility. This was caused by plastic deformation of the ductile, amorphous material under load, creating a large surface for bonding. After lubrication, however, the bonding properties decreased significantly, which was caused by the presence of a lubricant film. Hollow inulin particles have an increased compactibility as compared with solid particles and a strongly reduced lubricant sensitivity. Scanning electron micrographs show that hollow particles fragment before they start plastic deformation. This fragmentation behavior is supported by tablet surface area measurements and calculation of the buckling strength. This effect was responsible for both a higher crushing strength and a lower lubricant sensitivity as compared with solid inulin particles. CONCLUSIONS: Compactibility of inulin particles can be increased, and lubricant sensitivity can be decreased by using hollow instead of solid particles

The effects of cyclodextrins on the disposition of intravenously injected drugs in the rat

Naproxen and flurbiprofen form complexes with hydroxypropyl-beta-cyclodextrin; with stability constants of 2207 and 12515 M-1, respectively. However, only small fractions of the drug remain complexed when the drug-cyclodextrin complex is added to plasma in vitro. This result can be explained by albumin effectively competing with cyclodextrin for drug binding and by the simultaneous displacement of the drug from cyclodextrins by plasma cholesterol. Naproxen and flurbiprofen were administered intravenously to rats as cyclodextrin complexes. The disposition in the body of naproxen was not significantly altered by the complexation. This indicates that immediately after administration all drug is removed from the cyclodextrin complex. However, the initial distribution of flurbiprofen was changed upon complexation. Drug concentrations in liver, brain, kidney, and spleen were increased, indicating that hydroxypropyl-beta-cyclodextrin may improve the presentation of the flurbiprofen to biomembranes, as compared with plasma proteins. The effect was transient; 60 min after injection the differences in tissue concentration compared with controls were dissipated. Finally, the importance of protein binding in determining the mode of interaction of cyclodextrins on drug disposition is discussed