Publications by authors named "R P Holm"

Aim: It was the aim of this study to compare two different dry reverse micelle (RM) preparation methods for the incorporation of hydrophilic drugs into oral self-emulsifying drug delivery systems (SEDDS).

Methods: Cationic ethacridine lactate, anionic fluorescein sodium salt and the antibiotic peptide bacitracin were solubilized in RM containing sodium docusate, soy phosphatidylcholine and sorbitan monooleate in highly lipophilic oils such as squalane. In the dry addition (DA) method, drugs were directly added to empty RM in their powder form.

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Co-delivering dual-drug systems have proven to be effective in, for example, anticancer therapy or HIV prophylaxis due to a higher target selectivity and therapeutic efficacy from compound synergism. However, various challenges regarding physical stability can arise during the formulation definition when multiple drug compounds are included in the same formulation. In this work, the focus was on aqueous suspensions, which could be applied as long-acting injectable formulations to release the drug compounds over weeks to months after administration.

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Rat pharmacokinetic studies are commonly utilized in early discovery to support absorption, distribution, metabolism, and excretion optimization of active pharmaceutical ingredients (APIs). The aim of this work was to compare exposures from fit-for-purpose oral suspension and solution formulations in rats to guidance provided by the refined Developability Classification System (rDCS) with respect to identifying potential limits to oral absorption, formulation strategy selection, and to optimize oral bioavailability (BA). This investigation utilized six diverse APIs covering a large range of biorelevant solubility, metabolic stability, and oral BA in rats.

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The aim of this study was to develop an alternative strategy to sufficiently increase the lipophilicity of anionic model macromolecules (MM) without the use of cationic counterions. Enoxaparin (ENO), insulin (INS) and poly-L-glutamic acid (PLG) were ion paired with anionic surfactants (sodium decanoate (DEC), sodium dodecyl sulfate (SDS), sodium stearate (SS) and sodium octadecyl sulfate (SOS)), mediated by divalent cations such as magnesium, calcium and zinc. Complexes were evaluated regarding their precipitation efficiency and logD.

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Article Synopsis
  • The dual centrifugation method is an efficient tool for preparing submicron pharmaceutical suspensions by enabling the simultaneous milling of 40 samples, but more research is needed to fully understand how different process variables affect particle sizes.
  • Key factors influencing particle size include milling speed, bead size, and bead loading, while rotor temperature had no significant impact when polysorbate 20 was used.
  • The study found that optimal conditions, such as higher milling speeds and smaller beads, led to faster size reductions, achieving target sizes in about 30 minutes for specific compounds like cinnarizine, haloperidol, and indomethacin.
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