Biomedical subjects

J Yliruusi

Publications and source records attributed to J Yliruusi.

45 records · Page 3Linked to original sources

PubMed1998

The effect of compression force on surface structure, crushing strength, friability and disintegration time of erythromycin acistrate tablets.

The surface roughness of erythromycin acistrate tablets was studied by non-contact laser profilometry. Seven roughness parameters and 3D fractal dimension were examined. The mechanical properties (including crushing strength, friability and disintegration time) were determined, and SEM data were taken from the tablets. According to the results, the crushing strength and the disintegration time of the tablets increased with increasing compression force. At higher compression forces the crushing strength reached a constant level. The friability of the tablets behaved quite unexpectedly and minimum friability was observed at a compression force of 14 kN. Except for fractal dimension, the roughness parameters behaved very much in the same way as the friability of the tablets. The SEM data supported the friability and surface roughness data of the tablets.

Chemistry, Pharmaceutical↗

PubMed1998

Controlled release gel of ibuprofen and lidocaine in epidural use--analgesia and systemic absorption in pigs.

PURPOSE: Reduction of the frequency of injections and localization of the absorption of drug molecules to the injection site would be of great advantage in epidural pain treatment. The epidural use of a controlled release gel of lidocaine and ibuprofen was studied. METHODS: The effect of a poloxamer gel (25%) containing 2% lidocaine.HCl and 2% ibuprofen.Na on the duration of analgesia after epidural administration to pigs was compared with drug in solution. Analgesia was assessed by observing the motor function and the nociceptive reflex-withdrawal response to painful pressure stimulation on the feet. Pharmacokinetic and histological examinations were performed. RESULTS: Analgesia lasted significantly longer after epidural lidocaine gel injection in comparison with the solution. The gel prolonged the systemic absorption, thereby increasing the epidural availability of lidocaine for spinal analgesia. Although the absorption of ibuprofen was prolonged after epidural gel injection, the duration of analgesia as compared with the solution was not prolonged. After epidural injection, only slight inflammatory changes were observed in the tissue structures of the epidural space, but none in the spinal cord. CONCLUSIONS: These results demonstrate poloxamer gel to be a promising controlled-release, injectable epidural formulation for the management of pain.

Absorption↗

PubMed1997

Optimization of aqueous-based film coating of tablets performed by a side-vented pan-coating system.

The purpose of this research was to characterize the aqueous-based hydroxypropylmethylcellulose (HPMC) film coating of tablets utilizing a laboratory-scale side-vented pan-coating apparatus (Thai coater). The process and apparatus parameters of potential importance with respect to the final film quality were evaluated by using fractional factorial design (2(6-2)IV) and the process was optimized using response surface methodology (central composite design). Rotating speed of the pan was identified as a major parameter with respect to film thickness (weight increase; p < 0.05) and breaking strength (p < 0.05) of the aqueous HPMC film-coated tablets. Increasing the rotating speed from 5 rpm to 10 rpm resulted in a mean relative change of -43.9% and 2.4% of film thickness (weight increase) and breaking strength, respectively. As expected, inlet air temperature significantly affected the moisture content of the final film-coated tablets (p < 0.01) and the film thickness (weight increase; p < 0.05), but the effects on the other responses studied were minimal or negligible. Pneumatic spraying pressure and position of the spray gun (excluding angle of the gun) did not affect the responses studied. The process parameters relevant to a side-vented pan-coating process can be identified (by fractional factorial design) and, consequently, optimized (by central composite design) by using the factorial design approach.

Chemistry, Pharmaceutical↗

PubMed1995

Controlled release of lidocaine from injectable gels and efficacy in rat sciatic nerve block.

PURPOSE: Methods of delaying the action of local anesthetics are important, since short duration of action limits their use in the treatment of postoperative and chronic pain. The present study evaluated the use of low-viscosity gels in prolonging the release of lidocaine. METHODS: Release of lidocaine from 2% lidocaine.HCl containing methylcellulose (MC), hydroxypropylmethylcellulose (HPMC), sodiumcarboxymethyl cellulose (CMC), and poloxamer 407 (PO) gels was studied in phosphate buffer, pH 7.4, at 37 degrees C. Commercial metylcellulose gel (MCcom) served as control. The in vivo efficacy of the respective gel formulations were evaluated in rats. The gel was injected into the vicinity of the sciatic nerve and nociception and motor function were tested. RESULTS: The cumulative amount of lidocaine released during 8 hr was slowest from the PO gel, followed by the CMC, HPMC and MC gels. The antinociceptive effect was not prevented by the motor block and lasted longest with the PO gel. Good linear and rank order correlation was obtained between in vitro and in vivo results. The microscopic examination of the tissue samples revealed only mild or no irritation of the skeletal muscle tissue by the PO, HPMC, and CMC gels. CONCLUSIONS: Based on these results poloxamer gel proved to be the most promising carrier for lidocaine.

Animals↗

PubMed1995

Compression of lactose, glucose and mannitol granules.

The effect of the amount of granulation liquid, compression speed and maximum compression force on then compressibility and compactibility of lactose, glucose and mannitol granules was studied. The porosity based on the geometrical shape and the uniformity of weight of tablets was also studied. Lactose and mannitol granules showed a greater compressibility than glucose granules. Mannitol granules produced the hardest tablets and lactose and glucose the weakest. The change in the amount of granulation liquid caused changes both in the granule porosity and in the amount of binder; this was attributed to differences in tablet strength. All parameters studied were relatively insensitive to changing speeds of compression in the range used, except for the breaking force of mannitol tablets, which was greatest with the lowest speed of compression. All granule masses showed a relatively good continuous flow suitable for table production. Tablets compressed from lactose granules had the best uniformity of weight of the tablets studied.

Dosage Forms↗

PubMedDate not supplied

The use of different time/temperature combinations in the optimization of sterilization of Ringers/glucose infusion solution.

The effect of sterilization temperature and sterilization efficacy (F0) on the amount of 5-hydroxymethyl-2-furaldehyde (5-HMF) and glucose, number of particles generated and color of Ringers/glucose infusion solution is described. The infusion solution was a 5% glucose solution containing Ringer-type electrolytes. The solutions were autoclaved in a pilot scale autoclave using different temperature/time combinations to produce the target F0 values of 10, 15, 20 and 25 minutes. The amounts of 5-HMF and glucose were determined by HPLC. The use of the shortest possible sterilization cycle to yield the target F0 resulted in the lowest 5-HMF concentrations in the Ringers/glucose infusion solutions studied. The spectrochromatograms of the sterilized solutions showed that glucose is degraded into various degradation products in the presence of Ringer-type electrolytes. It was also demonstrated by SEM/EDX that a significant part of the particles result from the leaching of the silicon oil used in the manufacture of rubber stoppers for LVP solutions. The number of particles generated in different solutions and the particle size distributions were determined with a Coulter-Counter. The particle size distributions show no clear correlation between sterilization process conditions and the number of particles. The results show that it is possible to minimize the amount of 5-HMF generated even when the same F0 is used, by choosing the highest sterilization temperature possible. This also leads in practice to the shorter sterilization processes, saving both process time and energy.

Furaldehyde↗

PubMedDate not supplied

Comparison of different rubber stoppers; the effect of sterilization on the number of particles released.

The effect of sterilization on the number of particles released from five different types of rubber stoppers, as well as on their surface roughness and elemental composition before and after sterilization is described. The stoppers were immersed in 200 ml of 0.9% sodium chloride solution in conical flasks. The number of particles released into the sodium chloride solution was measured by Coulter Counter. The surface roughness and the elemental composition of the stoppers were determined by SEM/EDX. All measurements were made both before and after sterilization at 121 degrees C to F0 15 mins. The number of particles released from a stopper during sterilization varies considerably between different stoppers and even between different batches of the same stopper. The only non-siliconized stopper in this study performed well. The absence of surface siliconization may have contributed to this performance. The scanning electron micrographs revealed well the differences in the surface roughness of the stoppers. The sterilization generally increases the surface roughness of the samples. The x-ray microanalysis revealed that the elemental composition of the stoppers may vary not only between different types of stoppers but also between different batches of the same stopper.

Drug Packaging↗

PubMedDate not supplied

Optimization of moist heat sterilization.

The use of different combinations of sterilization time and temperature in a pilot scale autoclave, GEV 612 AR-2 (Getinge Ab, Sweden), in optimizing the sterilization process was studied. All three programs used had the same sterilization efficacy (F0 = 15 minutes) but different sterilization temperatures (116, 121, and 126 degrees C) and total process times (98, 57, and 44 minutes). The heat distribution during the sterilization phase was, in all cases, very uniform, the greatest difference being 0.5 degrees C. Also the F0 values differed only by +/- 0.5 minutes from each other. The F0 value increases linearly with all programs until the beginning of the cooling phase. The main effect of different sterilization temperatures on the cumulative F0 curves is an increase in the slope of the curves with increasing sterilization temperature. First order temperature change constants were determined both for the heating phase and the cooling phase. The numeric values of the rate constants for the heating and the cooling phases were 0.20 +/- 0.03 and 0.046 +/- 0.005 min-1, respectively. It is concluded that the pilot autoclave used in this study controls the sterilization process very accurately. The observed variations between F0 values at different positions in the autoclave chamber are acceptable. On the basis of this study an accurately engineered and controlled autoclave is required in process optimization. It also is possible to use higher sterilization temperatures than usually suggested in pharmacopeias and thus to shorten the process time.

Hot Temperature↗

PubMedDate not supplied

Polymorphic changes of mannitol during freeze-drying: effect of surface-active agents.

The effect of polysorbate 80 on the crystalline properties of mannitol during freeze-drying was studied. Crystallinity and polymorphism play an important role in, e.g., the solubility and stability of freeze-dried products. Polysorbate 80 had an effect on both the polymorphism and the crystallinity of freeze-dried mannitol.

Crystallization↗