A sustained controlled release formulation of soil nitrogen based on nitrate-layered double hydroxide nanoparticle material

The pharmacokinetics of a 2.5 mg immediate release (IR) formulation of indapamide was compared to a 1.5 mg sustained release (SR) formulation of indapamide after single and repeated oral administration dose using double blind randomised cross-over studies. In the first study, 12 subjects received a single dose of each treatment: IR fasted, SR fasted or with food. In the second study one tablet of either formulation was administered daily for one week at breakfast. In each study, blood samples were collected pre dose (Cmin) and up to 120 h after the last dose. Urine was collected over the dosing interval (24 h). Following a single oral administration the SR formulation had a lower dose-normalised Cmax compared to the IR formulation (17.6 +/- 6.3 vs. 39.3 +/- 11.0 ng x mL(-1), respectively), a much longer t(max) (12.3 +/- 0.4 vs. 0.8 +/- 0.3 h) and a greater t75 (15.3 +/- 6.1 vs. 1.8 +/- 1.4 h) but there were no differences in dose-normalised AUC (559 +/- 125 and 564 +/- 146 ng x h x mL(-1)) nor in t(1/2z) values (14.8 +/- 2.8 vs. 18.4 +/- 13.4 h). The SR formulation clearly demonstrated sustained release characteristics as compared to the IR formulation. Food co-administration had no effect on dose-normalised AUC for the SR formulation. After repeated administration, steady-state was achieved by day 5. The absorption rate of the SR formulation was lower and the 24 h peak-to-trough fluctuation was 4-fold lower compared to the IR formulation. After dose correction there wasno change in AUC, (726 +/- 207 and 690 +/- 183 ng x mL(-1) x h for SR and IR, respectively). The elimination parameters (t(1,2z), Ae(tau), and CLr) remained unchanged. The SR formulation showed sustained release of indapamide with a reduction in peak concentration, while steady-state level was not affected by formulations. The two formulations have the same bioavailability.

Background5-flucytosine (5FC) is used for the treatment of cryptococcal meningoencephalitis (CM) in patients with advanced HIV. The current dosing is four times a day involving high risks of low adherence...

Sustained release (SR) formulations of paracetamol (acetaminophen) have been introduced in several countries to provide lasting pain relief and reduced risk of rebound pain. However, few studies have evaluated the safety of paracetamol SR formulations. To assess the available published safety data regarding SR formulations of paracetamol, the EMBASE and MEDLINE databases were searched from 1980 to June 2003 for published worldwide human experience with paracetamol SR formulations. All publications that included any information about ingestion of any paracetamol SR formulation were systematically reviewed and abstracted by trained staff. The literature searches returned a total of 14 references containing safety data on paracetamol SR. In addition, the Toxic Exposure Surveillance System (TESS) of the American Association of Poison Control Centers (AAPCC) database was searched for human exposure cases. The TESS database yielded 3003 cases from 1994 to 2002 that involved a paracetamol SR product. The available information indicates that the adverse event and safety profile of paracetamol SR is very similar to immediate release (IR) formulations of paracetamol. During therapeutic use, minor effects such as gastrointestinal upset and headache may occur. The rate of these effects varies substantially among studies but overall does not appear to be different between the SR and IR formulations of paracetamol. Overdose with paracetamol SR is expected to cause liver injury similar to overdose with IR formulations. The number of human exposure cases has increased since introduction of the SR formulation; however, sales of the SR formulation amounted to 7.5% of all paracetamol sales but accounted for 2.5% of the cases reported to poison centres. There were two deaths recorded in the TESS database: both were the result of multiple drug ingestion. No cases of death or unusual types of toxicity have been described from an overdose of paracetamol SR alone.

The purpose of the study was clarify the effect of the cathepsin K inhibitor ONO-5334 on bone resortion markers using sustained release (SR) formulations with different pharmacokinetic (PK) patterns, and identify the optimal SR formulation. The PK profiles and pharmacodynamic effect on bone resorption markers of 4 SR candidates formulations were evaluated in healthy postmenopausal women within a randomized, 2-part, open-label crossover study. In Part A, subject received a single dose of each formulation orally in the fed state. In Part B, two selected formulations were evaluated in the fasted state. From the results from Part A, C(max) was reduced and plasma concentrations of ONO-5334 were sustained with all SR formulations compared with an immediate release tablet. In pharmacodynamics, the level of C-terminal telopeptide of type I collagen (CTX) in serum and urine were inhibited with SR tablets rather than with granules. C max and area under the concentration-time curve from time 0 to the last measurable time point (AUC(0-t)) of SR tablets were higher than those of granules. From Part B, C max in the fasted condition was lower than that in the fed condition with two SR tablets. In contrast, C(24 h) in the fasted condition was slightly higher than that in the fed condition, but AUC(0-t) was similar. The inhibitory effect on CTX in serum and urine may depend on the PK pattern of ONO-5334. The SR tablets was well tolerated in postmenopausal women and has the optimal SR profiles on pharmacodynamics effect on bone resortion markers and PK profile. These results suggest that SR tablets of ONO-5334 are an excellent drug candidate for osteoporosis.

Pharmacokinetic Comparison of Sustained- and Immediate-Release Oral Formulations of Cilostazol in Healthy Korean Subjects: A Randomized, Open-Label, 3-Part, Sequential, 2-Period, Crossover, Single-Dose, Food-Effect, and Multiple-Dose Study

Establishment of a suitable animal model to evaluate sustained release (SR) formulations is very important because it reduces the development time of SR formulations. Beagle dogs are often used to evaluate prototype formulations since they can be directly administered powder, such as drug substance. However, the physiological condition of dogs is very different to that of humans. Therefore, the benefits of utilizing beagle dogs for the evaluation of modified release formulations such as sustained release formulations and enteric-coated formulations are doubtful. To clarify the best animal and/or experimental technique for the evaluation of modified release formulations, we investigated dipyridamole pharmacokinetics from prototype sustained release granules by utilizing beagle dogs, propantheline bromide-treated (PBT) beagle dogs, and miniature pigs. In normal dogs, the intestinal absorption and sustained release effect of dipyridamole decreased in the 20mg sustained release granule. However, in PBT dogs, a sustained release effect was observed in the 45mg sustained release granule, and its bioavailability was also maintained. Accordingly, PBT dogs could be the best to evaluate sustained release formulations such as tablets and granules, and the use of miniature pigs might be better to evaluate granules with equal to or less than 1mm diameter.

Pharmacokinetic approach to the rational design of controlled or sustained release formulations

Nifedipine is one of calcium channel blockers that commonly used clinically to treat hypertension and angina in Egyptian patients. A sustained-release (SR) formulation of nifedipine is available in the Egyptian community and administered twice daily. This study aimed to to compare the pharmacokinetics and safety profiles of a 20 mg SR and IR (immediate release) formulation of nifedipine after single-dose administration in healthy Egyptian subjects. Randomized, crossed open-label two- way clinical trial, in 16 healthy adult volunteers, of 24.75±5.20 years, with BMI 23.26±1.756 were assessed. Blood samples were collected at predefined times for 48 h and analyzed for Nifedipine plasma concentrations using validated reversed phase liquid chromatography method with ultraviolet detection. Pharmacokinetics was determined using non- compartmental model pharmacokinetics and analyzed using one-way ANOVA (P≤0.05). Following a single oral administration, SR formulation had a lower Cmax, compared to IR formulation (54.46±17.75 , 107.45±29.85 ng/mL, respectively), and Tmax was significantly longer (2.97 vs. 1.13 h) for the SR and IR formulation, respectively. There was no significant difference between the SR and the IR formulations for AUC0-last and AUC0-∞ (326.7±98.28 vs. 309.27±105.53 ng·h·mL-1 and 380.9 ± 105.24 vs. 334.36±108.1 ng·h·mL-1, respectively). SR formulation of nifedipine showed similar pharmacokinetics to the IR Formulation (F%=1.049), but it additionally allows a less frequent administration. Therefore, The nifedipine SR and IR formulations were well tolerated and displayed comparable safety profiles.

Donepezil Dosing Strategies: Pharmacokinetic Considerations

Assessment of the relative and absolute bioavailability of immediate release and sustained release formulations of metoclopramide. Assessment of the effect of a high-fat meal on the pharmacokinetics of sustained release metoclopramide. In a balanced 4-way crossover study in 16 healthy male volunteers, a sustained release (SR) formulation of metoclopramide was compared with a solution for injection (A) and an immediate release tablet (B). The SR formulation was administered after a fasting period (C) as well as after a high-fat meal (D). A single dose of 30 mg metoclopramide was investigated in each treatment. Metoclopramide concentrations were determined by HPLC. The absolute bioavailability of the sustained release formulation (fasting state) was 58% and thus about 17% lower than the bioavailability of the immediate release formulation. Comparing the treatments C (sustained release, fasting state) and D (sustained release, high-fat meal) no significant influence of food on the absorption of sustained release metoclopramide could be detected.

The relationship between blood pressure (BP) and cardiovascular risk is clearly established; hypertension increases the rate of cardiovascular. High systolic blood pressure (SBP) may be the main parameter involved in cardiovascular morbidity and mortality. The benefit of lowering BP, particularly with diuretics has been proven in many outcome studies. Indapamide, a thiazide-type diuretic, was available for many years at a dosage of 2.5 mg in an immediate release formulation. A new sustained release (SR) formulation has been developed in order to allow the same antihypertensive efficacy with a better acceptability profile. This paper reviews the pharmacology of indapamide 1.5 mg SR from the bench to the bedside. Indapamide has a dual mechanism of action: diuretic effect at the level of the distal tubule in the kidney and a direct vascular effect, both of which contribute to the antihypertensive efficacy of the drug. The SR formulation contains a hydrophilic matrix, which delivers a smoother pharmacokinetic profile. This avoids unnecessary plasma peak concentrations, which may be associated with side effects. Indapamide SR has now been extensively used in hypertensive patients, including those at increased risk, for example elderly or diabetic patients. It has been shown to decrease BP, particularly SBP, with 24-h efficacy, allowing a once-daily dosage. Studies have demonstrated BP lowering to be at least as effective as all major therapeutic classes including the more recent antihypertensive drugs. Beyond BP decrease, indapamide SR has also been shown to protect against hypertensive target-organ damage in the heart and the kidney and to have a favorable metabolic profile. A broad evidence-base has accumulated to support the benefit of indapamide 1.5 mg SR in hypertensive patients, alone or as part of combination therapy, as recommended by the majority of guidelines.

Nowadays, pharmaceutical technology and research for new drugs and formulations is of great importance, as scientists attempt to discover even more revolutionary and efficient methods to treat various diseases. At the same time the correct dosing and site targeting are equally important for clinical success. Research in sustained drug release systems is very promising towards such a direction, while it offers advantages and potential rewards contrary to traditional therapy. The drug plasma concentrations remain inside the therapeutic range for a longer time period compared to the conventional formulations. In addition, sustained release formulations may increase the likelihood for the patient to respond to the therapy, since drug formulations are generally characterized by one daily given dose. The rate at which a drug is released from a sustained-release formulation depends upon many factors, while excipients play the most important role. Most sustained release formulations are based on biodegradable polymers in the form of a drug-encapsulating matrix or membrane. Examples range from monolithic devices, polymer-coated capsules and implant devices, hydrogels, to injectable systems based on suspensions of micro-, nanospheres or polymer solutions. The advantages and disadvantages of these different formulation systems are being extensively discussed in the present review.

In regulatory guidelines for bioequivalence (BE) assessment, the definitions of AUC for primary assessment are different in ICH countries, i.e., AUC from zero to the last sampling point (AUCall) in Japan, AUC from zero to infinity (AUCinf) or AUC from zero to the last measurable point (AUClast) in the US, and AUClast in the EU. To assure sufficient accuracy of truncated AUC for BE assessment, the ratio of truncated AUC (AUCall or AUClast) to AUCinf should be more than 80% both in Japanese and EU guidelines. We investigated how the difference in the definition of truncated AUC affects BE assessment of sustained release (SR) formulation. Our simulation result demonstrated that AUCall/AUCinf could be ≥80% despite AUClast/AUCinf being <80% and AUCall failed to detect formulation difference. In Japanese package inserts of generic drugs in SR formulation, there were products for which AUCall/AUCinf was ≥80% though AUClast/AUCinf was <80%. In conclusion, it was confirmed that the difference in definition of truncated AUC affected the judgment of validity of truncated AUC for BE assessment, and AUCall could fail to detect the substantially different in vivo dissolution profile of generic drugs with SR formulation from the original drug.

pH-Dependent Protein Chemical Degradation as a Representation of Effective pH Around Proteins Within Polymer-Based Sustained Release Formulations.

An Assessment of the Pharmacokinetics of a Sustained-release Formulation of a Tramadol/Acetaminophen Combination in Healthy Subjects