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PubMed1995

Prospective study of fluconazole suspension for the treatment of oesophageal candidiasis in patients with AIDS.

BACKGROUND: Oesophageal candidiasis is the most common cause of oesophageal symptoms in patients with AIDS. Antifungal therapy, given as a suspension, may be better tolerated than capsules or tablets in children or patients with oesophageal symptoms. We performed a prospective study of the safety and efficacy of fluconazole suspension. METHODS: Patients with HIV infection; odynophagia, dysphagia, or retrosternal pain; endoscopic evidence of white plaques or exudate in the oesophagus; and microscopic confirmation of fungal infection on biopsy or brushing specimens were eligible. Patients received fluconazole oral suspension (200 mg loading dose followed by 100 mg q.d.s.). Therapy was continued for 2 weeks after symptom resolution. Repeat endoscopy was performed after completion of therapy. RESULTS: Forty-two patients enrolled in the study: 40 were male, mean (+/- s.e.) age was 37 +/- 2 years and mean CD4 cell count was 67 +/- 14/mm3. One patient was not evaluable because he received amphotericin during the first week of therapy. Symptoms resolved in all 41 evaluable patients; 17 (41%) had resolution by 1 week, 37 (90%) by 2 weeks, and 40 (98%) by 3 weeks. Endoscopic resolution occurred in 35 (95%) of 37 patients who underwent repeat endoscopy. Adverse events (skin rash in 1, nausea/vomiting in 2, elevated liver tests in 2) led to early termination of therapy in 5 patients, all of whom had clinical and endoscopic cure. CONCLUSIONS: Symptoms resolved in 100% of patients with AIDS and oesophageal candidiasis receiving an oral suspension of fluconazole, and 90% of patients had symptom resolution within 2 weeks. Determining whether the more rapid clinical cure in this study, compared with a previous trial which employed capsules, is related to an additional topical antifungal effect of the suspension, will require further study.

AIDS-Related Opportunistic Infections↗

PubMed1995

A new approach to methotrexate and lipiodol suspensions for ectopic pregnancy: preliminary in vitro and animal experiments.

OBJECTIVES: To measure and evaluate the in vitro release of MTX from suspensions of methotrexate (MTX) and lipiodol (LPD), and to investigate the MTX concentration and fertility rate using an animal model. METHODS: This study was divided into three components: a) An in vitro Release Study, b) Animal Study No. 1 (concentration of tissue and plasma levels), and c) Animal Study No. 2 (fertility rate after MTX suspension). RESULT: The releasing rate in vitro was more rapid with MTX-S (MTX dissolved in saline) than with either MTX-LPD (MTX dissolved in lipiodol) or MTX-LPD-PC (MTX suspended in lipiodol and phosphatidylcholin, i.e., MTX suspension). The tissue concentration tended to be higher with an MTX suspension than with MTX-S. There was no significant difference in the fertility rate or the nidation index among the 3 groups (Groups 1, 2, and 3). CONCLUSION: The injection of an MTX suspension is useful for increasing the tissue concentration and maintaining the long-term effectiveness of MTX, and this technique might offer a new approach in the treatment of ectopic pregnancy (EP) or in second-line therapy for persistent EP.

Animals↗

PubMedDate not supplied

Single dose comparison of the relative bioavailability of phenytoin suspension and extended capsules.

There is presently only one preparation of phenytoin approved for once-daily dosing--extended phenytoin sodium capsules. We have observed many hospitalized patients switched from either this preparation or the intravenous form of phenytoin to phenytoin oral suspension. The bioavailability and single dose pharmacokinetics of extended phenytoin sodium capsules (Dilantin Kapseals) and phenytoin oral suspension (Dilantin oral suspension) were compared in seven healthy adult volunteers. Each subject was administered both three 100-mg Dilantin Kapseals (276 mg free acid) and 11 ml (275 mg) Dilantin-125 oral suspension in a randomized cross-over design with a 1-week washout period between preparations. Blood samples were drawn over 78 h after the administration of each preparation for determination of serum phenytoin concentration. In addition, total urinary output was collected for 48 h. Statistical analysis consisted of a comparison of the area under the curve (AUC) from time zero to 48 h and time-to-peak concentration using a two-tailed paired t test at a level of significance of p less than 0.05. The total alpha level was 0.10. No significant differences were found between the two preparations. The power of detecting a 15% difference in AUC was 0.80, and the power of detecting a 5-h difference in time to peak was 0.52. Following is a summarization of the pharmacokinetic parameters (capsules mean +/- 1 SD; suspension mean +/- 1 SD).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

Effects of cell lysis on the rheological behavior of red blood cell suspensions.

Rheological studies of lysed cell suspensions are performed with a magneto acoustic ball microrheometer. Two methods for lysing the cells are developed in order to provide cell volume concentrations identical to control intact cell suspensions. The first uses a freeze-thaw technique and the second uses sonication. It is found that cell suspensions disrupted by sonication have a lower viscosity than intact suspensions, whereas cell suspensions lysed by the freeze-thaw method exhibit a higher viscosity. Sonication is discovered to have a detrimental impact on the cell membrane, and to cause complete destruction of the cell membrane structure. Measurements of the steady state viscosity show that indeed the presence of the membrane is not detected, and that what is measured is mainly the viscosity of the hemoglobin solution. On the other hand, freeze-thaw results indicate that at least two phenomena occur. The first phenomenon, occurring during the first freeze-thaw cycle, produces an increase in viscosity and in viscoelasticity. The second one, taking place after subsequent freeze-thaw cycles, induces a decrease in the bulk rheological properties. Several possible mechanisms are presented to explain the observed phenomena.

Elasticity↗

PubMed1991

Comparative efficacy of amphotericin B colloidal dispersion and amphotericin B deoxycholate suspension in treatment of murine coccidioidomycosis.

The efficacy of a novel sterol-complexed preparation of amphotericin B, amphotericin B colloidal dispersion, was compared with that of deoxycholate-complexed amphotericin B in an acute murine model of systemic coccidioidomycosis. Mice (CD-1, female) were infected intravenously with 180 or 200 arthroconidia of Coccidioides immitis, and intravenous therapy was begun 3 days later. Six doses in various regimens of either preparation were given over 14 days, and deaths were tallied for an additional 35 days. All regimens that were not acutely lethal prolonged the survival of mice over that of controls (P less than 0.001). Quantitative determination of residual burdens of C. immitis in the spleen, liver, and lungs of survivors revealed that the colloidal dispersion was not as effective as the deoxycholate suspension on a milligram-per-kilogram basis. Deoxycholate suspension at 1.3 mg/kg cleared the organs in all mice, whereas colloidal dispersion at 5.0 mg/kg was the lowest dose that cleared organisms from all animals. Lower doses cleared organisms from fewer animals or cleared only selected organs. Deoxycholate suspension was more efficacious than colloidal dispersion in clearing C. immitis from the liver or lungs (P less than 0.05 to 0.01, dose and organ dependent) at identical doses. No overt toxicity was observed in mice treated with colloidal dispersion at 10 mg/kg. In contrast, deoxycholate suspension at 2.0 mg/kg was acutely toxic; 50% of the treated mice died after treatment. The two complexes were not equivalent on a milligram-per-kilogram basis; the deoxycholate suspension was three to four times more efficacious and also greater than 5- to greater than or equal to 8-fold more toxic. Thus, the therapeutic index of the colloidal dispersion complex is greater than that of the deoxycholate complex. The amount of amphotericin B per dose could also be increased when given as a colloidal dispersion to an optimally level. Amphotericin B colloidal dispersion shows promise for the therapy of disseminated coccidioidomycosis and should be tested in other animal models and in humans.

Amphotericin B↗

PubMed1996

Pharmacokinetics of fluconazole in saliva and plasma after administration of an oral suspension and capsules.

The concentrations of fluconazole were determined at steady state in the saliva and plasma of 10 healthy volunteers after ingestion of fluconazole as capsules and after flushing the mouth for 2 min with the same dose formulated as an oral suspension and swallowing of the drug. Saliva and plasma samples were analyzed by a validated high-performance liquid chromatographic assay. Flushing and swallowing of the oral suspension resulted in a significantly (P = 0.005) higher mean area under the concentration-versus-time curve (AUC) from 0 to 24 h in saliva (89.13 +/- 23.42 mg.h/liter) than that obtained after ingestion of the same dose as capsules (69.27 +/- 12.89 mg . h/liter). The calculated mean maximum concentration in saliva just after swallowing of the suspension was 97.99 +/- 6.12 mg/liter. The peak fluconazole concentration in saliva after the ingestion of the capsules was 3.55 +/- 0.40 mg/liter. The fluconazole oral suspension and capsules resulted in comparable concentrations and AUCs in plasma. Thus, because of a higher local level of drug exposure in terms of both higher peak concentrations in saliva and a higher salivary AUC, the fluconazole oral suspension has theoretical advantages over the capsule formulation in the treatment of oropharyngeal candidiases.

Administration, Oral↗

PubMed1997

Effect of a 14-day hindlimb suspension on cytosolic Ca2+ concentration in rat portal vein myocytes.

Effects of a 14-day hindlimb suspension were examined on increases in cytosolic Ca2+ concentration ([Ca2+]i) evoked by vasoactive compounds and on Ca2+ channels in rat portal vein myocytes. The maximal increases in [Ca2+]i elicited by caffeine, norepinephrine, and angiotensin II were reduced by 30-50% in suspended rats, and complete recovery was obtained 4 days after suspension removal. In contrast, voltage-gated Ca2+ channels were unaffected by hindlimb suspension. Using both confocal microscopy and the patch-clamp technique, we measured local increases in [Ca2+]i which corresponded to activation of a small number of ryanodine-sensitive Ca(2+)-release channels (Ca2+ sparks) and D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3]-gated Ca2+ channels. After hindlimb suspension, these local Ca2+ events, as well as the Ca2+ sensitivity of ryanodine-sensitive Ca2+ release channels, remained unchanged. In contrast, the propagated Ca2+ responses (Ca2+ waves) were significantly reduced in parallel with a noticeable inhibition of [3H]ryanodine binding to vascular membranes. Taken together, these results suggest that inhibition of the vasoconstrictor-induced increases in [Ca2+]i during long-term suspension may be related to a reduction of the number of functional ryanodine-sensitive and Ins(1,4,5)P3-gated channels in the sarcoplasmic reticulum of rat portal vein myocytes.

Angiotensin II↗

PubMed1999

Effects of hindlimb suspension on cytosolic Ca2+ and [3H]ryanodine binding in cardiac myocytes.

Effects of a 14-day hindlimb suspension were examined on [3H]ryanodine binding to rat ventricular microsomes and on cytosolic Ca2+ concentration ([Ca2+]i) and voltage-dependent Ca2+ channels in isolated ventricular myocytes. In suspended rats, the amplitude of the twitch [Ca2+]i transient was increased without significant modifications of the basal [Ca2+]i and sarcoplasmic reticulum content. Because cell capacitance, L-type Ca2+-current density, and Ca2+-channel gating were not significantly modified after suspension, the increase in [Ca2+]i was expected to reside in a change in ryanodine receptors. Scatchard analysis of [3H]ryanodine binding revealed that suspension enhanced binding by increasing the affinity of the receptors for [3H]ryanodine without affecting the maximal binding capacity. Both Ca2+-release channel activity and [3H]ryanodine binding are modulated by Ca2+. However, the Ca2+ sensitivity of [3H]ryanodine binding remained unchanged after suspension. Taken together, these results suggest that the increase in twitch [Ca2+]i transients after suspension may result from a change in the intrinsic properties of the ryanodine receptors but not from a change in the expression level of these receptors.

Animals↗

PubMed2002

A new solution-based intranasal triamcinolone acetonide formulation in patients with perennial allergic rhinitis: how does the pharmacokinetic/pharmacodynamic profile for cortisol suppression compare with an aqueous suspension-based formulation?

The present study was undertaken to describe the pharmacokinetics of a new solution-based intranasal triamcinolone acetonideformulation (Tri-Nasal) in patients with perennial allergic rhinitis and to use a pharmacokinetic/pharmacodynamic (PK/PD) simulation approach to compare the potential effects on plasma cortisol with that of an aqueous suspension-based nasal triamcinolone acetonide formulation (Nasacort AQ). Data from an open-label, randomized, three-way crossover study in patients with perennial allergic rhinitis receiving three doses (100, 200, and 400 microg) of a nasal solution-based triamcinolone acetonide formulation (Tri-Nasal) over 7 days were used to describe the pharmacokinetics of this formulation. Available literature data for a suspension-based aqueous triamcinolone acetonide formulation (Nasacort AQ) were used to describe its pharmacokinetic profile after similar single doses of 110, 220, and 440 microg. A PK/PD simulation approach was used to predict the anticipated cumulative cortisol suppression (CCS) of these two formulations. These simulations suggested a cortisol suppression of 8% to 16% for the single and steady-state doses of the solution-based product. Similar CCS estimates were predicted for equivalent doses of the aqueous suspension-based triamcinolone acetonide formulation with no difference between both formulations. Post hoc power analysis suggested that the predicted cortisol suppression is not likely to be significant for either preparation, including the clinically recommended doses of 200 and 220 microg of the solution-based and suspension-based formulations, respectively. In summary, based on the results of this PK/PD simulation, the plasma levels observed afternasal administration of the solution or the aqueous suspension are unlikely to induce a clinically relevant cortisol suppression, especially for the recommended dosing regimens of 200 and 220 microg/day.

Administration, Intranasal↗

PubMed1993

Stability of spironolactone in an extemporaneously prepared suspension at two temperatures.

OBJECTIVE: To determine the stability of spironolactone in an extemporaneously prepared suspension at 22 and 4 degrees C over a three-month storage period. DESIGN: Spironolactone suspension (1 mg/mL) was prepared in syrup NF, carboxymethylcellulose, and purified water USP. The suspension was stored in ten amber glass prescription bottles; five were stored at 22 degrees C and five at 4 degrees C. Samples were drawn from each bottle and analyzed in duplicate (n = 10) on days 0, 7, 14, 28, 42, 56, 70, and 91. Spironolactone concentrations were measured by a reproducible and stability-indicating HPLC method. Inspection of visual and pH changes also was performed on each study day. RESULTS: The mean concentration of spironolactone was always higher than 98 percent of its initial concentration. The pH and appearance of the suspension did not change substantially. CONCLUSIONS: Spironolactone was stable in a suspension containing syrup, carboxymethylcellulose, and purified water for three months during storage in amber glass bottles at both 22 and 4 degrees C.

Carboxymethylcellulose Sodium↗

PubMed2001

Hydrocortisone suspension and hydrocortisone tablets are not bioequivalent in the treatment of children with congenital adrenal hyperplasia.

In July 1998, Cortef oral suspension (Pharmacia & Upjohn) was reformulated changing the suspending agent tragacanth to xanthan gum. We subsequently observed suboptimal control of hormone levels in a group of children with classic congenital adrenal hyperplasia, despite increasing doses of Cortef suspension and stringent instructions to parents regarding shaking of the bottles of medication. Nineteen children receiving Cortef and fludrocortisone therapy were changed to hydrocortisone tablets and fludrocortisone, with a 10 percent reduction in hydrocortisone dose. A significant decrease in 17-hydroxyprogesterone (235 +/- 120 vs. 27 +/- 7 nmol/L; p</=0.001) and androstenedione (18.9 +/- 18.0 vs. 3.5 +/- 3.5 nmol/L; p=0.002) was observed 4-6 weeks later. Twenty-one percent (4/19) had 17-hydroxyprogesterone and androstenedione levels at or below the detection limit of the assay. Despite a significant reduction in glucocorticoid dose (19.6 +/- 4.7 vs. 17.6 +/- 3.9 mg/M(2)/day; p<0.001), eight children experienced significant weight gain and appetite increase, three experienced trouble sleeping, four experienced moodiness, and three developed hypertension requiring a decrease in fludrocortisone therapy. Hydrocortisone dose was further decreased to 15.2 +/- 2.6 mg/M(2)/day with resolution of symptoms. We conclude that Cortef suspension and hydrocortisone tablets are not bioequivalent and the reformulated form of hydrocortisone oral suspension was inadequate in the control of children with congenital adrenal hyperplasia. Cortef suspension has been recalled as a result of these data.

17-alpha-Hydroxyprogesterone↗

PubMed2026

[Effect of electroacupuncture combined with suspension exercise therapy on lower limb motor function in elderly patients with post-stroke spastic hemiplegia].

OBJECTIVE: To observe the efficacy of electroacupuncture (EA) combined with suspension exercise therapy in elderly patients with post-stroke spastic hemiplegia and its effect on lower limb motor function. METHODS: A total of 120 elderly patients with post-stroke spastic hemiplegia were enrolled. Using a 2×2 factorial design, all the patients were assigned to a group A (conventional treatment), a group B (conventional treatment combined with suspension exercise therapy), a group C (conventional treatment combined with EA at Jiaji [EX-B2] and limb acupoints), and a group D(conventional treatment combined with suspension exercise therapy and EA at Jiaji [EX-B2] and limb acupoints), with 30 patients in each group. The main acupoints were bilateral Jiaji (EX-B2) points at the C2-C7, T2-T12, L1-L5, and S1 segments. The adjunct acupoints included Jianyu (LI15), Binao (LI14), Huantiao (GB30), Chengfu (BL36), etc. on the affected side.Continuous wave was applied at a frequency of 100 Hz with a current intensity of 1.5-3.0 mA, and needles were retained for 30 min, once daily for 4 weeks. Before treatment and after 2 and 4 weeks of treatment, the modified Ashworth scale (MAS),Fugl-Meyer assessment (FMA), Berg balance scale (BBS), and Barthel index scores were evaluated in the four groups. Root mean square (RMS) values of surface electromyography (sEMG) of the erector spinae and rectus abdominis muscles on the affected side, as well as balance function indexes, including the mean pressure symmetry index (SI), contact area SI, ellipse area, and displacement distances of the center of pressure in the anteroposterior (AP) and mediolateral (ML) directions, were measured. Clinical efficacy was also compared among the four groups. RESULTS: After 2 and 4 weeks of treatment, MAS scores in all groups were lower than those before treatment (P<0.05), whereas FMA, BBS, and Barthel index scores were higher than those before treatment (P<0.05). After 4 weeks of treatment, MAS scores were lower than those after 2 weeks of treatment (P<0.05), whereas FMA, BBS, and Barthel index scores were higher than those after 2 weeks of treatment (P<0.05) in the four groups. At both 2 and 4 weeks after treatment, group D had lower MAS scores (P<0.05) and higher FMA,BBS, and Barthel index scores (P<0.05) than the other three groups. After 2 and 4 weeks of treatment, RMS values of sEMG of the erector spinae and rectus abdominis muscles on the affected side at all tested angles were higher than those before treatment in all groups (P<0.05), and the values after 4 weeks of treatment were higher than those after 2 weeks of treatment(P<0.05). At both 2 and 4 weeks after treatment, all these indexes in the group D were higher than those in the other three groups (P<0.05). After 2 and 4 weeks of treatment, the mean pressure SI, contact area SI and ellipse area of each group were lower than those before treatment (P<0.05). After 4 weeks of treatment, the mean pressure SI, contact area SI and ellipse area of each group were lower than those after 2 weeks of treatment (P<0.05). After 2 and 4 weeks of treatment, the AP displacement distances of groups A, C and D were lower than those before treatment (P<0.05), and after 4 weeks of treatment, the AP displacement distances of groups A, C and D were lower than those after 2 weeks of treatment (P<0.05);after 2 weeks of treatment, there was no statistically significant difference in AP displacement distance in the group B compared with before treatment (P>0.05), and after 4 weeks of treatment, the AP displacement distance of group B was lower than that before treatment (P<0.05). After 2 weeks of treatment, there was no statistically significant difference in ML displacement distance in group A compared with before treatment (P>0.05); after 4 weeks of treatment, the ML displacement distance of group A was lower than that before treatment (P<0.05). After 2 and 4 weeks of treatment, there was no statistically significant difference in ML displacement distance in the group B compared with that before treatment (P>0.05).After 2 and 4 weeks of treatment, the ML displacement distances of groups C and D were lower than those before treatment(P<0.05), and after 4 weeks of treatment, the ML displacement distances of groups C and D were lower than those after 2 weeks of treatment (P<0.05). At both 2 and 4 weeks after treatment, mean pressure SI, contact area SI, ellipse area, and AP and ML displacement distances in the group D were lower than those in the other three groups (P<0.05). Factorial analysis of variance showed that EA had the strongest main effect on FMA score (F=6.243, P<0.05), suspension exercise therapy had the strongest main effect on BBS score (F=6.292, P<0.05), and the interaction effect was most significant for MAS score (F=5.941, P<0.05), indicating that the combined therapy produced a greater synergistic effect on reducing muscle tone than on the other outcome measures. The total effective rate in the group D was 93.3% (28/30), which was higher than those in the group A (53.3% [16/30]), group B (56.7% [17/30]), and group C (66.7% [20/30], P<0.05). CONCLUSION: EA combined with suspension exercise therapy could effectively promote the recovery of lower limb function in elderly patients with post-stroke spastic hemiplegia, improve motor and balance functions, and enhance activities of daily living.

Humans↗

PubMed1992

The treatment of falciparum malaria in children with halofantrine suspension.

Malaria treatment of children is particularly difficult because of the absence of palatable suspensions for young children. Halofantrine hydrochloride is available as a suspension which is both palatable and simple to administer, and has been studied in a number of trials in the past 5 years. Children (331) ranging from 4 months to 17 years of age (mean 4.7 years) were treated with the 5% suspension using various dose regimens and 364 children ranging from 4 months to 14 years of age (mean 5.7 years) were treated with the 2% suspension 6 hourly for 3 doses. Using the 3-dose regimen there were only 2/462 (0.4%) who failed to clear the initial parasitaemia. Recrudescence occurred in 28/367 (7.6%) children with evaluable follow up data. The mean parasite clearance time in this group was 57.1 h (n = 417) and the mean fever clearance time was 50.9 h (n = 325). Symptoms related to malaria cleared rapidly following treatment generally by 24-48 h post treatment. Side effects possibly related to treatment were uncommon but were similar to those reported in adults. The frequency of diarrhoea and abdominal pain was lower than that seen in adults and was also less frequent following multiple doses and the use of the more dilute suspension. Since there was evidence that the majority of recrudescences were seen in younger children or those living in areas with low or seasonal transmission it is recommended that a further course of treatment 7 days later is given to these patients to prevent recrudescence.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed2002

Comparison of paste and suspension formulations of omeprazole in the healing of gastric ulcers in racehorses in active training.

OBJECTIVE: To compare effects of a commercially available omeprazole paste and a compounded omeprazole suspension on healing of gastric ulcers in Thoroughbred racehorses in active training. DESIGN: Randomized controlled trial. ANIMALS: 32 horses with gastric ulcers. PROCEDURE: Horses were assigned to 2 groups on the basis of endoscopic gastric ulcer severity. Group-1 horses were treated with omeprazole suspension for 30 days and with omeprazole paste for an additional 30 days. Group-2 horses were treated with omeprazole paste for 30 days and omeprazole suspension for an additional 30 days. Serum omeprazole concentrations were measured in 4 additional healthy horses after administration of a single dose of each formulation. In all instances, omeprazole was administered at a dose of 4 mg/kg (1.8 mg/lb), p.o.. RESULTS: Ulcer severity scores on day 0 were not significantly different between groups. On day 30, ulcer severity score was significantly decreased, compared with day-0 score, in group-2 but not in group-1 horses. On day 60, ulcer severity score was significantly decreased, compared with day-0 and day-30 scores, in group-1 horses. In group-2 horses, ulcer severity score on day 60 was significantly lower than the day-0 score but was not significantly different from the day-30 score. Maximum observed serum omeprazole concentration and area under the concentration-time curve were significantly higher after administration of the paste versus the suspension formulation. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that although administration of the commercially available paste omeprazole formulation was effective in promoting healing of gastric ulcers in these horses, administration of the compounded omeprazole suspension was ineffective.

Animals↗

PubMedDate not supplied

Chemical, dissolution stability and microscopic evaluation of suspensions of ibuprofen and sustained release ibuprofen-wax microspheres.

Chemical stability studies of suspensions of ibuprofen powder and ibuprofen-wax microspheres were performed using an accelerated stability protocol with a modified high performance liquid chromatography (HPLC) procedure. The variables considered were pH, suspending agents and temperature. The study showed little or no chemical degradation in the different suspending agents after storage for three months. Dissolution stability was examined in suspensions of ibuprofen microspheres made from an optimized formulation with 17% drug loading. The storage temperature were 23, 37 and 45 degrees C. Other variables for the dissolution stability studies were suspending agents, wax types, suspending medium pH and microsphere size. Suspensions of ceresine wax microspheres stored at 37 degrees C showed faster drug release than room temperature storage, but suspensions stored at 45 degrees C showed an opposite effect. Microspheres suspended in syrup and stored at 37 degrees C had faster dissolution rates than microspheres suspended in methylcellulose at the same temperature, possibly as a result of an interaction between the syrup and the microsphere constituents. Suspensions of microcrystalline wax microspheres had better dissolution stability than microspheres made from ceresine wax. Higher suspending medium pH resulted in faster release of drug from the suspended microspheres, but particle size did not significantly affect the dissolution stability.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMedDate not supplied

The physical and chemical stability of suspensions of sustained-release diclofenac microspheres.

The major challenge in liquid sustained-release oral suspensions is to minimize drug diffusion into the suspending medium and to retain the original properties of the microparticles during storage. Diclofenac wax microspheres prepared by the hydrophobic congealable disperse phase method were formulated as a sustained release suspension and stored at three different temperatures (25, 37 and 45 degrees C) for 3 months, to evaluate the physical and chemical stability of the suspended microspheres. Suspensions of microspheres stored at ambient temperatures were both physically and chemically stable, but at higher temperatures, up to 45 degrees C, there was a decrease in drug release due to scaling and melting on the microsphere surface as observed by scanning electron microscopy. However, on prolonged storage, up to 90 days, especially at 45 degrees C, temperature became a dominant factor causing an increase in drug release. The suspension of diclofenac microspheres was chemically stable for 3 months, while the plain drug suspension exhibited slight degradation.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMedDate not supplied

Development of two stable oral suspensions of levodopa-carbidopa for children with amblyopia.

PURPOSE: To develop stable liquid dosage forms of levodopa-carbidopa for use in children with amblyopia. METHODS: Levodopa (100 mg) and carbidopa (25 mg) tablets were used to prepare the suspensions at 5 and 1.25 mg/mL, respectively. For each suspension, five bottles were stored at 25 degrees C and five at 4 degrees C. Three samples were taken from each bottle at 0, 7, 14, 28, 42, 56, 70, and 91 days (n=15). Levodopa-carbidopa concentrations for each sample were measured in duplicate by validated and stability-indicating high-performance liquid chromatographic method. RESULTS: The mean concentrations of levodopa-carbidopa in Ora Plus/Ora Sweet suspensions were 96% and 92% of the initial concentrations for 28 days at 25 degrees C, and 94% and 93% for 42 days at 4 degrees C. In the suspension containing ascorbic acid, the mean concentrations of levodopa-carbidopa were above 93% and 92% for 14 days at 25 degrees C, and 93% and 92% for 28 days at 4 degrees C. This liquid formulation was administered to 15 children (mean age: 5.6+/-1.4 years) with amblyopia. The number and type of adverse effects were similar in the levo-dopa-carbidopa versus placebo group. CONCLUSION: Levodopa-carbidopa in extemporaneous suspensions prepared in Ora Plus and Ora Sweet were stable for 28 days when stored at 25 degrees C and for 42 days at 4 degrees C. Our data suggest our liquid formulation may be used safely in children with amblyopia.

Administration, Oral↗

PubMed1999

Myogenin, MyoD, and myosin heavy chain isoform expression following hindlimb suspension.

BACKGROUND: Myogenin expression is associated with a slow myofiber phenotype, and MyoD expression is associated with a fast myofiber phenotype. Hindlimb suspension (HS) will induce muscular atrophy, and a transition from a slow to fast myofiber phenotype in the rat soleus. HYPOTHESIS: Hindlimb suspension will induce myofiber atrophy, and a slow to fast myofiber type transition with corresponding changes in myogenin and MyoD expression. METHODS: Myofiber phenotype was evaluated by electrophoretically separating the myosin heavy chain isoforms. Myogenin expression was evaluated by Northern analysis, while MyoD expression was evaluated by Northern analysis and semiquantitative RT-PCR. RESULT: After 28 d of hindlimb suspension, there was significantly (p < 0.05) less myosin heavy chain Type IIA, and more (p < 0.05) myosin heavy chain Type IIX in the soleus muscles of hindlimb suspended rats compared with soleus muscles from weight-bearing (WB) rats. Although there was a shift to a faster myosin heavy chain phenotype in soleus muscles from hindlimb suspended rats, there was no change in myogenin expression, and MyoD expression was undetectable by Northern analysis. Semi-quantitative RT-PCR revealed an up-regulation of MyoD expression following 14 d of hindlimb suspension. CONCLUSIONS: Myogenin expression levels do not change during the slow to fast myofiber phenotypic transition that occurs during hindlimb suspension; MyoD expression appears to increase at the same time as the phenotypic transition. Thus, MyoD expression or the Myogenin: MyoD mRNA ratio may be important in the phenotypic transition. Neither myogenin nor MyoD appear to play a critical role in the muscular atrophy that occurs during weightlessness.

Animals↗