Science and Risked-Based Stability Testing Strategies-a Test Case on the Global Implementation and Regulatory Reception.

The global regulatory implementation and acceptance of a science and risk-based stability (SRB) strategies for a stable drug product is reviewed. This stability strategy may also be referred to as "lean stability" since it includes a stability protocol reduction in the number of tests and time points than might normally be applied. A product line extension (new solid dosage form) for a well-understood product was used as a test case for this stability strategy. The drug product line extension was filed globally with a proposed reduction to analytical stability tests and frequency. This stability protocol is aligned with the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) Q1A (R2) stability guidelines (ICH: Guideline Q1A(R2), 2003), the World Health Organization (WHO) (WHO INT. [Online], 2020), and most country regulatory guidelines. Although this strategy was not accepted universally, the strategy enabled opportunities to engage in productive dialogs with regulatory authorities in several countries on how the case leveraged product understanding and development knowledge to develop a fit for purpose stability protocol. A persistent and consistent effort from industry to move toward product-specific protocols based on product knowledge and stability risk assessments should lead to further acceptance of science and risk-based stability strategies in all regions.

Enhancing the Dissolution Stability of Hard Gelatin Capsules Using Activated Carbon as a Packaging Component.

Hard gelatin capsule (HGC) shells are widely used to encapsulate drugs for oral delivery but are vulnerable to gelatin cross-linking, which can lead to slower and more variable in vitro dissolution rates. Adding proteolytic enzymes to the dissolution medium can attenuate these problems, but this complicates dissolution testing and is only permitted by some regulatory authorities. Here, we expand the scope of our previous work to demonstrate that canisters containing activated carbon (AC) or polymeric films embedded with AC particles can be used as packaging components to attenuate gelatin cross-linking and improve the dissolution stability of hard gelatin-encapsulated products under accelerated International Council for Harmonisation conditions. We packaged acetaminophen and diphenhydramine HCl HGCs with or without AC canisters in induction-sealed high-density polyethylene bottles and with or without AC films in stoppered glass vials and stored these samples at 50°C/75% relative humidity through 3 months and at 40°C/75% relative humidity for 6 months. Samples packaged with AC canisters or AC films dissolved more rapidly than samples packaged without AC when differences were observed. These results demonstrate that different sources and formats of AC can enhance the dissolution stability of HGCs packaged in bottles and other potential packaging systems such as blister cards.

Use of Activated Carbon in Packaging to Attenuate Formaldehyde-Induced and Formic Acid-Induced Degradation and Reduce Gelatin Cross-Linking in Solid Dosage Forms.

Formaldehyde and formic acid are reactive impurities found in commonly used excipients and can be responsible for limiting drug product shelf-life. Described here is the use of activated carbon in drug product packaging to attenuate formaldehyde-induced and formic acid-induced drug degradation in tablets and cross-linking in hard gelatin capsules. Several pharmaceutical products with known or potential vulnerabilities to formaldehyde-induced or formic acid-induced degradation or gelatin cross-linking were subjected to accelerated stability challenges in the presence and absence of activated carbon. The effects of time and storage conditions were determined. For all of the products studied, activated carbon attenuated drug degradation or gelatin cross-linking. This novel use of activated carbon in pharmaceutical packaging may be useful for enhancing the chemical stability of drug products or the dissolution stability of gelatin-containing dosage forms and may allow for the 1) extension of a drug product's shelf-life when the limiting attribute is a degradation product induced by a reactive impurity, 2) marketing of a drug product in hotter and more humid climatic zones than currently supported without the use of activated carbon, and 3) enhanced dissolution stability of products that are vulnerable to gelatin cross-linking.

Dissolution Similarity Requirements: How Similar or Dissimilar Are the Global Regulatory Expectations?

The objective of this article is to compare and contrast the international expectations associated with the model-independent similarity factor approach to comparing dissolution profiles. This comparison highlights globally divergent regulatory requirements to meet local dissolution similarity requirements. In effect, experiments customized to meet the current international regulatory expectations for dissolution and drug release unnecessarily increase manufacturing costs, hinder science and risk-based approaches, increase collective regulatory burden, reduce continuous improvement and innovation, and potentially delay patient access to urgently needed medication. Comparative assessment of regulatory differences in applying dissolution to demonstrate product similarity is crucial to reduce non-scientifically justified experiments and foster collaborative harmonization among global regulatory health authorities and the pharmaceutical industry.

Aqueous phosphoric acid as a mild reagent for deprotection of tert-butyl carbamates, esters, and ethers.

Aqueous phosphoric acid (85 wt %) is an effective, environmentally benign reagent for the deprotection of tert-butyl carbamates, tert-butyl esters, and tert-butyl ethers. The reaction conditions are mild and offer good selectivity in the presence of other acid-sensitive groups, including CBZ carbamates, azetidine, benzyl and methyl esters, TBDMS, and methyl phenyl ethers. The mildness of the reaction is further demonstrated in the synthesis of clarithromycin derivative, in which a tert-butyl ester is removed in the presence of cyclic carbamate, lactone, ketal, acetate ester, and epimerizable methyl ketone functionalities. The reaction preserves the stereochemical integrity of the substrates. The reactions are high yielding, and the workup is convenient.